Images taken covertly in the 1970s have taken on a new purpose in a recent glaciology study.
'Declassified images taken during the Cold War show that the thickness of Himalayan glaciers has been declining twice as fast since 2000. A new study released on 19 June 2019 in Science Advances compares the thickness of 650 glaciers in the Central Himalaya over a 40-year period. The results relied on modern methods to digitize declassified film photographs taken by U.S. spy satellites between 1973 and 1976. The analysis revealed that even over large swaths of the Himalaya, which have a range of local climates and pollution levels, scientists found a detectable link between diminishing glacial ice and warming air temperature. “We see the clearest picture yet of how Himalayan glaciers have responded to climate change.”“We see the clearest picture yet of how Himalayan glaciers have responded to climate change,” first author and doctoral student at Columbia University Josh Maurer told Eos . “As temperatures continue to rise, ice loss will continue to accelerate.” He warned of drier days to come for those downstream as water stores melt away. Tracking glacier melt in the Himalaya can be a tricky business. Unlike some glaciers that recede as they melt, like Exit Glacier in Alaska, Himalayan glaciers often keep their spatial extent but simply become thin. The glacier loses mass, dwindling in height, but the change is difficult to assess from top-down snapshots, like those available in the 20th century when air temperatures began to ramp up due to global warming. Starting in the 1950s, however, the United States designed sophisticated cameras to spy on the former Soviet Union and allied European and Asian countries. The KH-9 Hexagon spy satellite, first launched in 1971, snapped images from hundreds of kilometers above at such fine resolution that U.S. officials could count the number of launchpads at Soviet missile sites. Images from Hexagon and other spy satellites were declassified in the 2000s, giving scientists a new trove of historical data. An artist’s illustration outlines the KH-9 Hexagon satellite and its camera components. The satellite used nearly 100 kilometers (60 miles) of film per deployment. Credit: National Reconnaissance Office The declassified Hexagon images present researchers with a new angle that traditional satellite images couldn’t: The spy satellite took photos overlapping by more than 50%, so that U.S. intelligence officials back in Washington could create three-dimensional images. Having the overlapping images allowed Maurer to extract not only the extent of the glaciers but also their volume over time. “That third dimension is really important,” Maurer explained. He created a digital elevation model for the Himalayan region using the old black-and-white film and compared it with three-dimensional images taken today. A Landscape Melting Away The latest study shows the quickening pace of the Himalayan glacial melt. According to the research, the glaciers shrank by an average of a quarter of a meter between 1975 and 2000. Since 2000, however, the glaciers lost twice that amount over the same length of time. The glaciers now have just under three quarters of their 1975 ice mass.All told, Himalayan glaciers now lose billions of tons of ice per year, Maurer said, enough to fill 3.2 million Olympic-sized swimming pools annually. The glaciers now have just under three quarters of their 1975 ice mass. The effect wasn’t isolated to just one part of the Central Himalaya. “We see a rather homogenous pattern of ice loss across a large and climatically complex region,” Maurer explained. Using measurements from weather stations in the area, the study points to global warming as the underlying cause. “The correlation we observed between rising air temperatures and acceleration of glacier melts over the past 4 decades really highlights how vulnerable these glaciers are to climate change,” Maurer noted. The 650 glaciers considered in the study contain only about half the glacial mass in the Central Himalaya. But Maurer said that the study is representative of the region, because their analysis included the largest glaciers, which have the most to lose, and spans a wide area. Glaciologist Etienne Berthier, from the French National Centre for Scientific Research, called the paper’s doubling pace of ice loss “very convincing” but also said that scientists should wait until further study to attribute ice melt to warming temperatures. “This work paves the way toward more thorough attribution studies,” he told Eos . Maurer plans to apply this method to other parts of High Mountain Asia, such as the Hindu Kush mountain range at the Afghan and Pakistani border. He said that the Hexagon program didn’t cover just U.S. adversaries but has images worldwide. “They were taking images wherever they could, all over the globe,” Maurer said. “There are lots of images that are just sitting there in an archive waiting to be used.” —Jenessa Duncombe (@jrdscience), News Writing and Production Fellow'
Images taken covertly in the 1970s have taken on a new purpose in a recent glaciology study.
The twice-daily ebb and flow of the sea have the power to change the planet. Weak tides could have allowed Earth to freeze over, and strong tides may have given vertebrates a leg up on land.
'When is it high tide? Do we have a spring tide? These questions are asked by tourists getting ready for a day at the beach and by sailors arriving at port. The tide makes a difference to their day. But tides may have an influence on far larger timescales, too. At the recent General Assembly of the European Geosciences Union in Vienna, Austria, two presentations suggested that tides may have changed the history of our planet on more than one occasion. Snowball Earth Tides may have helped initiate a “snowball Earth” phase by becoming exceptionally weak, according to Mattias Green of the School of Ocean Sciences at Bangor University in the United Kingdom, along with researchers from the University of Lisbon in Portugal, Monash University in Australia, and Northwestern University in the United States. They reached this conclusion from model calculations of tides the world over, taking into account the location of continents, ocean depth, and ice cover. Originally, Green told Eos , he and his colleagues were looking for arguments against the snowball Earth hypothesis, which posits that during the Cryogenian, the geologic period from 720 million to 635 million years ago, two extreme glaciations covered the planet with ice, except possibly for a band along the equator.Tidal weakness supported the stable cold phase of the planet by starving ice sheets of any warm water that could have kept them in check. There is no consensus, however, that glaciation really was that extreme. Green thought that if tides turned out to be strong during the Cryogenian, it might not be possible for so much ice to exist. “We know that the tides on Earth today are important around the Antarctic and in Greenland,” Green said. “They lift the ice, which sets up stress fractures. But most importantly, the tide brings warm water in, which melts the ice on the underside. The cold, fresh meltwater would then insulate the ice, but the tide gets rid of that. There are studies that suggest that if you don’t have tides in Antarctica, the melt rate would be a quarter of what it is now.” After the calculations were complete, Green had to conclude that the opposite was true in the Cryogenian: Tides were exceptionally weak, about 10% of their present amplitude. “They were doing nothing,” Green said. But that doesn’t mean that tides played no role during snowball Earth. On the contrary, their weakness supported the stable cold phase of the planet by starving ice sheets of any warm water that could have kept them in check. “All the other processes that the tides are contributing to, like vertical transport, ocean circulation, [they aren’t] there. So it’s possible that along with a lot of other things, this is one potential mechanism that helped bring along the snowball stage,” said Green. One initial reason for weak tides during the Cryogenian was that the familiar continents of Earth were gathered into one supercontinent, surrounded by one ocean. According to an earlier study by Green, when there are more continents and smaller oceans, the resonance of tidal flows is more likely to be amplified, just like water will slosh higher and higher in a bathtub if you move your body at just the right beat. Right now, this is the reason tides in the Atlantic are particularly high. Once Earth entered the snowball stage, for reasons that are still debated, conditions on the planet further dampened the tides, according to Green. Water turning into ice means shallower oceans and thus less water for the Moon and the Sun to pull around. Friction on the underside of the ice means tidal currents are weakened. The feedback would work in the other direction once the supercontinent started breaking up and the ice lost its grip on Earth and its tides. The Cryogenian ended. Tidal Change in Evolution In a warmer world, life flourished in the sea and eventually on land. And in that transition, too, tides may have played a pivotal role, according to another study by Green, together with Steven Balbus of the University of Oxford in the United Kingdom and Per Ahlberg and Hannah Byrne of Uppsala University in Sweden. Researchers argue that during the Devonian, tides forced certain lobe-finned fish to make the move onto land. These organisms were the ancestors of modern tetrapods.The researchers argue that during the Devonian, 419 million to 359 million years ago, tides forced certain lobe-finned fish to make the move onto land. These organisms were the ancestors of modern tetrapods, or four-limbed vertebrates, including humans. An explanation for that move onto land is needed, Balbus told Eos . “That’s not something that naturally occurs. Fish don’t come out of the ocean regularly and make themselves happy on land. The other way is very common. Lots of species love to go back to the ocean; they evolve, and they become very fishlike: whales, porpoises, and before them ichthyosaurs. They can swim, and if they need oxygen, they go up. If you’re a fish on the land and you need to have water over your gills, what are you going to do? So it requires some kind of special impetus for that to happen.” That impetus, he proposed in a 2014 paper in Proceedings of the Royal Society A , could have come from the phenomenon of spring tides and their opposite, neap tides. These tidal variances occur because the gravitational pulls of the Sun and the Moon, comparable in size, sometimes reinforce and sometimes work against each other. “For the spring tides, the ocean comes up very far onto the land. The next time there’s a high tide, it doesn’t come as far,” Balbus explained. “That means there’s an isolated tidal pool. If you’re a fish, it’s not good.” That’s because with Earth tides being what they are, a fish will have to wait roughly half a month for a splash of water and a chance to escape the pool—unless it can call on some extra capabilities. “If the fish can somehow flail out, and wouldn’t die immediately, there would be another place reasonably nearby to get to, that was replenished a little more often, because it’s closer to the sea,” Balbus said. In other words, on a coast with high tides, even rudimentary locomotion would be advantageous for a fish, making the development of fleshy, lobed fins into weight-bearing limbs a good evolutionary adaptation. Balbus and his colleagues investigated tidal patterns and evolution by analyzing the geography of 400 million years ago. “The idea is to take reconstructions of what the continents during the Devonian looked like, work out what the Moon’s orbit was back then, and ask: What tidal patterns were there?” His team was the perfect multidisciplinary group, Balbus said: he himself is an astrophysicist, Green is an oceanographer, and Ahlberg and Byrne are paleontologists. They did the calculations and at the Vienna conference presented two regions in what are now southern China and the Baltics that seem particularly promising to establish a correlation between tidal range and the emergence of early tetrapods.“We are a long way from proving [our theory]. People argue about the reasons why these fish developed limbs; you can think of all kinds of reasons why that would be good.” “There are bays with very high tidal responses,” Balbus said. “And, in fact, they are associated with very interesting fossil records that tell us that a large radiation of key transitional fish species occurred. And the early tetrapods were located there.” An article on the findings has been submitted to the Proceedings of the National Academy of Sciences of the United States of America , but Balbus admits that “we are a long way from proving it. People argue about the reasons why these fish developed limbs; you can think of all kinds of reasons why that would be good.” One way to clinch the debate would be for the group to point to locations that had very high tides in the Devonian and then find transitional or early tetrapod fossils there. “That would be a very important vindication, if we can calculate where to look for fossils,” said Balbus. Tides on Earth are nowadays a bit stronger than they were in the Devonian, and all over the world, tidal pools are a common feature of the coastal landscape. So the same evolutionary pressure for fish to adapt to live on land still exists, Balbus agrees. Modern fish, however, have a problem that the lobe-finned fish of the Devonian did not: “God help the fish that can’t do very well on land. There are a lot more creatures now that will have them for breakfast than when this first happened. But there are fish that live in these intertidal regions, and you can see what kind of biological adaptations they’ve developed. Air breathing capacity and also some sort of mobility. In Asia, perches actually climb trees, and they inhabit areas that I guess are similar to the sort of areas we are talking about here, extensive swamps.” Such behavior shows these areas to be, he said, the most likely places for vertebrates to have come on shore for the first time. “And it seems to have happened.” —Bas den Hond (email@example.com), Science Writer'
No direct causal connection exists between coastal sea level changes and the strength of the North Atlantic’s overturning circulation, according to new, longer-term observational records.
'The Atlantic Meridional Overturning Circulation (AMOC), a system of currents in the Atlantic Ocean that transports warm surface waters northward and cooler, deeper waters southward, is a crucial component of Earth’s climate system. Because the AMOC is part of a conveyor belt of oceanic circulation that redistributes heat around the globe, variability in its strength can have significant climate consequences. Previous modeling studies have concluded that the AMOC’s strength is negatively correlated to sea level along the New England coastline, such that a weakening of the North Atlantic Current or the Gulf Stream leads to a rise in sea level at the coast. This relationship, however, has been difficult to detect in observational records. Now Piecuch et al. are challenging the conventional wisdom that a direct causal connection exists between the AMOC and coastal sea level in this region. After obtaining monthly RAPID monitoring program observations of the overturning circulation at 26°N and monthly sea level records collected between 2004 and 2017 at eight New England tide gauges, the team examined the physical relationships between the two records. The authors concluded that widespread atmospheric teleconnections can simultaneously trigger changes in both the AMOC at 26°N and coastal New England sea level. Although these phenomena are temporally correlated with each other, the team concludes that they are not causally linked. The researchers argue that the local atmospheric forcing mechanisms driving coastal New England sea level change are instead related to the North Atlantic Oscillation and other surface atmospheric variations. Although this study represents a valuable contribution to improving our understanding of how coastal sea level is related to oceanic circulation, the authors caution that their results apply to only the time period studied and that the negative correlation between coastal sea level and overturning at 26°N should not be considered representative of the AMOC at other latitudes. The researchers suggest that future studies could shed new light on the processes occurring at higher latitudes, where new AMOC monitoring arrays have recently been established. ( Geophysical Research Letters , https://doi.org/10.1029/2019GL083073, 2019) —Terri Cook, Freelance Writer'
Volcanic craters act as giant horns that emit intense low-frequency sounds. Changes in this infrasound may be used to track rising lava lakes and identify signals of future eruptions.
'Chile’s Villarrica volcano erupted suddenly on 3 March 2015, disgorging a lava fountain more than 2 kilometers high. The eruption—Villarrica’s first in 30 years—was unexpected in terms of its rapid onset and its violence. It was also remarkably short-lived. Within an hour, the explosive activity had ended. Within about a month, the volcano had returned to its usual state, which featured a roiling lava lake situated deep within the steep-walled summit crater. We now recognize that Villarrica’s changing sounds provided a warning that lava was rising within the crater.Forecasting such violent eruptions is the holy grail for applied volcano science. Toward this objective, volcanologists deploy seismometers to detect tremors, tiltmeters and GPS to identify swelling, and multispectral detectors to monitor gas and heat output. Infrasound sensors, which record the low-frequency sounds produced by volcanoes, are an increasingly important component of this diverse tool kit. Volcanologists traditionally have used infrasound surveillance to both count explosions and track eruption intensity, important capabilities when the view of the volcano is obscured [ Fee and Matoza , 2013; Johnson and Ripepe , 2011]. Recent studies have demonstrated that infrasound monitoring can also be used to identify important eruption precursors [e.g., Ripepe et al. , 2018]. Villarrica gave indications of its unrest through the changing character of its infrasound. We now recognize that Villarrica’s changing sounds provided a warning that lava was rising within the crater [ Johnson et al. , 2018a]. These observations were made serendipitously as part of a National Science Foundation–sponsored research project, Volcano Acoustics: From Vent to Receiver, that studied the long-distance propagation of the infrasound produced at Villarrica. During the 2015 field expedition, we installed sensors on the summit and flanks of the volcano. Although the 3 March eruption destroyed the summit deployment, sensors outside the damage zone collected data that yielded a full chronology of the volcano’s increasing unrest. Volcanoes as Giant Musical Instruments Volcanoes generate infrasound, low-frequency sounds below the threshold of human perception. Despite varied eruptive behaviors, many volcanoes radiate their most intense sounds within a few octaves of 1 hertz, corresponding to sound wavelengths of hundreds of meters. It is no coincidence that this dimension is similar to the dimension of volcanic craters, which play a critical role in modulating the radiated sound [e.g., Kim et al. , 2015]. As with a musical horn, a volcano’s timbre and pitch are particular to a crater’s shape.In many ways, a volcano is like a giant musical instrument. As with volcanoes, the size of a musical horn controls the pitch of the sound it makes: Bigger horns make lower-pitched sounds. Musical sounds tend to be pleasing because of the horn’s resonance; air pressure waves sloshing back and forth within a length of brass tube project sonorously from the horn’s bell. The shape of the bell’s flare is important and controls whether a note is sharp and short or rich and reverberating. This quality, which is independent of a note’s frequency or loudness, is referred to broadly as its timbre. As with a musical horn, a volcano’s timbre and pitch are particular to a crater’s shape. Volcanoes with deep craters have a tendency to produce low-frequency sounds, whereas shallow craters radiate higher-frequency sounds [ Spina et al. , 2014; Richardson et al. , 2014]. Narrow conduits often resonate for extended periods, but broad, dishlike craters might not reverberate at all. Although volcanic sound sources can be varied, vents at the bottom of a crater acting as mouthpieces often generate infrasound. The violent expulsion of gas from vents or from a lava lake surface can induce the crater to resonate. Volcanic Unrest and Changing Sound Quality Fig. 1. During the few days leading up to Villarrica’s 3 March 2015 explosion, the volcano’s characteristic explosion infrasound changed (top and bottom). Colored disks represent the spatial equivalents of the respective infrasound time series, which were recorded 4 kilometers from the vent; oscillations are mostly absent on 2 March. Waveforms on 27 February had well-defined oscillations that were mostly absent by 2 March (middle). Draped topography was created by the authors from the Shuttle Radar Topography Mission digital elevation model using an image from NASA Earth Observatory. VID and VIC are the stations that recorded the waveform data. Volcano infrasound merits particular attention when it changes over time. This can happen when volcanoes change their shape as crater walls slump, floors collapse, or a lava lake rises and falls. Villarrica’s lava lake dynamism, for instance, is considered to be responsible for changing infrasound leading up to the violent eruption in 2015. Frequency fluctuations had previously been attributed to oscillating lava lake stages [ Richardson et al. , 2014], but in 2015, scientists noted a systematic variation that led up to the violent eruption on 3 March. A study by Johnson et al . [2018a] reported two primary observations: The frequency content of the sounds increased around 1 March (from 0.7 to 0.95 hertz), and the timbre changed (Figure 1). Prior to 1 March, reverberations were evident, but afterward, the sound became like a thunk. In other words, the crater’s acoustic source had dampened. Villarrica’s crater resembles a funnel, with a conical upper section and a narrow conduit beneath. The absence of resonance in early March is important because according to numerical models, it signifies a high stand of the lava lake situated near the flaring section of the crater. During Villarrica’s typical background state, the surface of the lava lake is deeper—and often hidden—within the vertical-walled shaft. By 2 March, the infrasound signals suggest that the lava lake was approaching the crater rim; the horn had become a loudspeaker, as illustrated in the video below. The trigger for the dramatic 3 March lava fountain, which started at 3:00 a.m. local time, remains enigmatic, but the end result was a violent paroxysm that caused property damage, forced thousands of people to evacuate the area, and made worldwide headlines. Infrasound observations told us that the surface of the lava lake had reached a high level several days before the eruption. These insights may help us to anticipate future eruptions at open-vent volcanoes. Volcano Resonance on Steroids Every volcano has a unique infrasound signature. Compared with Volcán Villarrica, whose resonance evolved during a few days from noticeable to absent, infrasound from Ecuador’s Cotopaxi volcano was notable because it rang consistently in 2016 (Figure 2). Villarrica’s infrasound oscillations lasted cumulatively for a few seconds, but a single oscillation at Cotopaxi lasted for 5 seconds. As many as 16 oscillations were detected in some of the infrasound signals, which, incredibly, lasted more than a minute (Figure 3). Fig. 2. Cotopaxi and Villarrica volcano photos and satellite imagery from NASA Earth Observatory show the relative size of their summit craters, which produce discrete infrasound signals. Yellow squares in both satellite images are 1 square kilometer. Credit: NASA International Space Station photo archive (Cotopaxi satellite photo), NASA Earth Observatory Fig. 3. The infrasound signal time series illustrates the nature of the resonance at Villarrica and Cotopaxi (top left). Each waveform is a composite stack of 50 events, which occurred during 1 day at Villarrica and during 6 months at Cotopaxi. A detail of the first 10 seconds from this time series shows the contrast in sound signatures from the two volcanoes (top right). Frequency spectra peak at 0.2 hertz for Cotopaxi and 0.75 hertz for Villarrica; damping factors α indicate the time constant for characteristic decay in reciprocal seconds (bottom). .. A study of the Cotopaxi events recorded in 2016 refers to these beautiful signals as infrasound tornillos, the Spanish word for screws, because the pressure recording resembles a screw’s profile [ Johnson et al. , 2018b]. Such waveforms attest to an exceptionally low damping and thus a high quality factor of the crater acoustic source. (Sources with higher quality factors have less damping, and they ring or vibrate longer.) If Villarrica is like a large trombone, with a leadpipe length that changes over time, then Cotopaxi is like a giant tuba, with relatively unchanging dimensions during much of 2015 and 2016. After explosions in August 2015 opened up Cotopaxi’s crater, the visible conduit extended steeply downward from its 5,900-meter summit. Throughout the first half of 2016, the crater bottom was not visible to aircraft flying over the summit. Aerial observations showed a vertical-walled crater at least 200 meters deep, a dimension corroborated by the modeled infrasound, which suggested a 350-meter shaft. Sources of Crater Resonance Infrasound’s journey from volcano source to receiver can be understood only by considering the dramatic modulating effects produced by crater topography [ Kim et al. , 2015]. It is most plausible that both Cotopaxi’s impressive tornillos and Villarrica’s subdued oscillations are induced by short-duration impulses occurring at the bottom of their craters. An abrupt explosion, or an impulse, contains a broad spectrum of frequencies; however, only those that excite the crater in resonance are well sustained. Typically, volcano scientists who analyze remote infrasound recordings are generally less interested in the oscillatory “breathing” of the crater outlet (i.e., its infrasound resonance) than in extracting important information about the explosion’s source, such as its duration or mass flux. It is this information that contributes to our growing understanding of how gas accumulates and separates from magma and how it powers volcanic explosions. However, with recent developments in the understanding of crater acoustic effects, we are better poised to recover important parameters related to the sources of explosions. Cotopaxi and Villarrica represent just two of the dozens of volcanoes active worldwide where infrasound is contributing to our fundamental understanding of eruption dynamics and to our ability to forecast future paroxysms. Acknowledgments This work was funded in part by National Science Foundation grants EAR-0838562 and EAR-1830976 and by the Fulbright Scholar Program.'
Coral reefs face threats including habitat destruction, pollution, and climate change. A novel set of interventions could help them persist in rapidly degrading environmental conditions.
'With coral reefs under threat worldwide, a new report examines and provides a framework to assess novel intervention options that could provide a way forward to protect them. In the face of threats including habitat destruction, pollution, and climate change, the aim of these interventions is “to increase the ability of these coral reefs to persist in these rapidly degrading environmental conditions,” according to the report, A Decision Framework for Interventions to Increase the Persistence and Resilience of Coral Reefs , which was released on 12 June by the National Academies of Sciences, Engineering, and Medicine (NASEM). The tools themselves, which also were detailed by NASEM in 2018, include genetic and reproductive interventions such as managed selection and breeding; physiological interventions including pre-exposure of corals to increase their tolerance to stress factors; environmental interventions such as marine and atmospheric shading; and managed relocations of coral populations. “These new tools are needed because established approaches for managing coral reefs are neither sufficient, nor designed, to preserve corals in a changing climate.”Seven of the 23 examined tools already have been field-tested in specific locations, and all of the interventions have potential risks that need to be carefully weighed against perceived benefits, according to the report, which was requested and funded by the National Oceanic and Atmospheric Administration (NOAA), with additional support provided by the Paul G. Allen Family Foundation. For instance, different types of managed selection present the risk of a decrease in genetic variation. Genetic manipulation could alter the wrong genes and result in unknown risks. Another tool, shading, would alter light regimes. “These new tools are needed because established approaches for managing coral reefs are neither sufficient, nor designed, to preserve corals in a changing climate,” the report states. “Coral interventions that address the impacts of ocean warming and ocean acidification are part of a three-pronged approach for coral reef management that crucially also includes the mitigation of greenhouse gas emissions and the alleviation of local stressors.” Managers and decision makers “are faced with the task of evaluating the benefits and risks of a growing number of interventions, separately and in combination,” the report continues. “The interventions have different risks, benefits, and feasibilities in different regions.” Because there is “no single generalizable approach” for coral reef interventions, the report recommends a structured and adaptive management framework that engages a wide range of stakeholders and that is tailored to local environmental and ecological settings, management objectives, and preferred intervention options. A Bridge to the Future “Mitigating [greenhouse gas] emissions is the only way that corals are going to be able to thrive into the far, far future,” Stephen Palumbi, chair of the NASEM committee that produced the report, said at a 12 June briefing. Palumbi, a coral scientist, is a professor of marine sciences and a senior fellow with the Woods Institute for the Environment at Stanford University. “But in this century, when we are hopefully getting a handle on mitigation of the emissions, and things will eventually be getting better by the century, it will take coral interventions now in order for those coral systems to bridge between now and the end of the century.” In an interview with Eos , Palumbi summed up the report: “Coral reefs are in trouble, there are some things we can do about them, and we now have the tools to begin to be able to make that work in the future.” “Corals are not just pretty things that we’d like to have around,” Palumbi said. “They support hundreds of millions of people.” Shallow-water coral reefs, which cover less than 1% of the Earth’s surface, conservatively provide an estimated $172 billion per year in benefits to people in the form of food production, property protection, and tourism, according to NOAA’s Coral Reef Conservation Program Strategic Plan. Moment of Opportunity There is “a moment of opportunity” to help protect coral reefs if these interventions are managed properly and are ready for deployment when needed.Marissa Baskett, a member of the NASEM committee that produced the report, told Eos that there is “a moment of opportunity” to help protect coral reefs if these interventions are managed properly and are ready for deployment when needed. “We have a variety of potential interventions that can increase coral persistence in the future,” said Baskett, an associate professor of environmental science and policy at the University of California, Davis. “All come with uncertainties and risks. But if we leverage that uncertainty, we can learn from the process to mitigate risk, maximize learning, and improve the future.” Baskett said that there needs to be a stakeholder-driven and scientifically driven process for understanding the potential risks and benefits of these interventions. “We have an extraordinary opportunity right now to be ready to deploy them when they are necessary” and to be proactive rather reactive, she said. Committee members also have briefed Congress, the White House, and NOAA about the report. NOAA, which received the report about a week ago, currently is developing its response, according to Tali Vardi, a coral scientist with ECS, a federal contracting company, who is NOAA’s point person to the NASEM study.“How do we stop just cataloging those declines and start putting our energy into doing things? That’s what I want this report to be.” “There is a lot of work to do” to protect coral reefs, she told Eos . “Reefs are disappearing while we sit here and chat.” Palumbi told Eos that he wants this report to make a real difference for the future of coral reefs. “Everybody I know who has worked on reefs for the last 20 or 30 years knows places that were fabulous and are virtually dead now. How do we turn that around? How do we stop just cataloging those declines and start putting our energy into doing things?” Palumbi said. “That’s what I want this report to be. I want it to be the foundation on which people say, there are things to do, there’s energy to do it. There’s a goal. We have to wrap it into climate mitigation. We have to wrap it into the local stressors thing. But there is a way forward. Let’s take it, because what are we going to do if we don’t take it?” —Randy Showstack (@RandyShowstack), Staff Writer'
High-resolution mapping efforts could improve predictions of coastal changes as glaciers shrink around the world.
'As climate change progresses, glaciers continue to retreat worldwide. In the Arctic, glacial meltwater delivers sediments and nutrients to fjords and, ultimately, to the ocean. New research by Normandeau et al. reveals how glacial retreat impacts downstream sediment delivery and associated currents in Arctic fjords. Heavier flows resulting from glacial retreat can boost the amount of sediment delivered to the mouths of rivers that empty into fjords, rapidly increasing the size of the river deltas. However, the links between glacial retreat and underwater delta dynamics are complex and have been poorly understood, limiting predictions of how, exactly, glacier retreat will reshape Arctic nearshore fjords. To get a better picture of this system, the authors of the new study mapped the underwater features of 31 river mouths in fjords along the eastern coast of Canada’s Baffin Island. The maps incorporated high-resolution bathymetric data collected over several years from aboard the R/V Nuliajuk and the CCGS Amundsen as part of the ArcticNet program. These mapping efforts revealed which deltas contained sediment waves, large-scale patterns in deposited sediment that are formed by the fast, downhill flow of sediment-laden water. These fast flows are known as turbidity currents, and their presence or absence depends on upstream glacial and watershed dynamics. Statistical analysis of links between the mapping data and watershed data compiled for each river mouth showed that the presence of turbidity currents depends on the presence and size of upstream glaciers, which erode material that becomes transported as sediment. However, if lakes form upstream from fjords during glacial retreat, they may trap sediment, keeping it from flowing downstream and halting turbidity currents. The researchers used these findings to create a model of evolving delta dynamics over the course of upstream glacial retreat. The model accounts for the formation of lakes that halt downstream turbidity currents, as well as reactivation of turbidity currents that may occur if lakes later fill up with sediment. The scientists applied their model to 644 rivers emptying into fjords along Baffin Island, predicting which are likely to contain turbidity currents. This work could help improve predictions of future coastal changes worldwide, including effects on marine ecosystems that rely on nutrients transported in sediments. It could also help refine understanding of past glacial retreat. ( Journal of Geophysical Research: Earth Surface , https://doi.org/10.1029/2018JF004970, 2019) —Sarah Stanley, Freelance Writer'
A new seafloor seismic network detected low-frequency tremor on the subduction zone interface offshore northern Japan, indicating regions of slow slip in close proximity to shallow megathrust events.
'Low frequency tremor is a newly discovered type of seismic activity indicative of slow slip of a fault, rather than the typical “fast” slip that occurs in regular earthquakes. While such activity has been discovered in many global subduction zones, it has yet to be identified in northern Japan. Tanaka et al.  report the discovery of shallow low-frequency tremors near the Japan Trench by using the newly installed seafloor seismic observation network (S-Net). They show that tremor activity in this region, co-located with low-frequency earthquakes, is distributed in two main clusters, separated by a gap where large earthquakes have nucleated and where aftershock activity of the 1994 Sanriku-Oki earthquake was also located. This indicates fairly rapid along-strike variations in the frictional properties of the shallow plate interface and helps us to better understand the driving mechanisms for both slow and regular earthquakes. Citation: Tanaka, S., Matsuzawa, T., & Asano, Y. . Shallow low‐frequency tremor in the northern Japan Trench subduction zone. Geophysical Research Letters , 46. https://doi.org/10.1029/2019GL082817 —Gavin P. Hayes, Editor, Geophysical Research Letters'
Do climate models truthfully mimic how drying soil affects land-surface budget partition?
'The way that Earth System Models (ESMs) represent the linkage between soil moisture and evapotranspiration is still poorly captured by diagnostics in most models. Gallego-Elvira et al.  apply a new method to extensive long-term satellite observations and reanalyze data of land-surface and air temperature across the globe. The study highlights world regions where ESMs capture the coupling well, such as in arid areas, and regions where models are unable to capture a realistic relationship between soil moisture and evapotranspiration, specifically, continental areas. The results are important for further model development, because soil moisture is known to be a strong contributor to temperature extremes. This research thus provides a useful platform for both global and regional climate models seeking to improve the description of land surface energy budgets. Citation: Gallego‐Elvira, B., Taylor, C. M., Harris, P. P., & Ghent, D. . Evaluation of regional‐scale soil moisture‐surface flux dynamics in Earth system models based on satellite observations of land surface temperature. Geophysical Research Letters , 46. https://doi.org/10.1029/2019GL082962 —Valeriy Ivanov, Editor, Geophysical Research Letters'
The tule fog in California’s Central Valley is notorious for causing delays and accidents throughout the region; however, a decrease in air pollutants is reducing the fog’s frequency.
'Bounded to the east by the Sierra Nevada mountains and to the west by the Coastal Range, California’s Central Valley is one of the most productive agricultural regions in the world. Some estimates indicate the region supplies more than half of the fruits, vegetables, and nuts grown in the United States. The valley is so hospitable to agriculture in part because of a unique meteorological phenomenon known as tule fog. The dense ground fog enshrouds the valley during the winter and provides a necessary winter chill that increases the productivity of fruit and nut trees. However, it also drastically reduces visibility around the region, particularly at night and in the early mornings. The bleary episodes rank as one of the primary causes of weather-related accidents in the state. Over the past 90 years, the frequency of tule fog has boomeranged dramatically. From 1930 to 1970, the fog’s frequency consistently climbed—cities like Fresno experienced an 85% increase in fog events. Yet starting around 1980, the fog began to dwindle. Weather observations indicate a 76% reduction in fog over the past 36 winters. Gray et al. investigated tule fog to determine the drivers behind its upward then downward trend and its year-to-year variability. The authors used the National Oceanic and Atmospheric Administration’s archives to craft a history of fog frequency dating to 1909. They used records from the National Climatic Data Center to stitch together a fog climatology that included data on temperature, dew point, precipitation, wind speed, and other climate variables. Additionally, they used Environmental Protection Agency data and local city inventories to evaluate how air pollution, specifically particulate matter (PM) and oxides of nitrogen (NO x ), affects the fog. NO x is a critical precursor to wintertime nitrate formation with a long observational record, making it an ideal proxy for PM. The authors discovered that annual fluctuations in fog occurrence are driven by local weather; of the climatic variables analyzed, dew point depression appeared to be the most critical measurement. The findings suggest that there has not been a decrease in the number of days with optimal fog conditions since 1930, but now nearly all tule fog events occur under optimal conditions, which was not the case 35 years ago. Long-term tule fog trends are instead driven by air pollution: Pollution and fog increased until 1970 and decreased after 1980 when effective controls and regulations were implemented in California. The results showed that under low dew point depression conditions, every 10 parts per billion decrease in NO x resulted in five fewer fog days per year. Changes in tule fog frequency affect the transportation, agriculture, drought resistance, and climate of California’s Central Valley, and these findings offer insights for managers and planners. Furthermore, the study reveals an unintended consequence of reducing air pollution. (Journal of Geophysical Research: Atmospheres , https://doi.org/10.1029/2018JD029419, 2019) —Aaron Sidder, Freelance Writer'
Former congressman Henry Waxman, who led efforts on sweeping environmental initiatives, is realistic about the obstacles presented by congressional Republicans and the Trump administration.
'“The biggest problem we face on climate is not that we need to come up with better ideas,” according to former U.S. Rep. Henry Waxman. “What we need is Republicans who will negotiate in good faith.”If some Republicans would be willing to seriously negotiate about climate change, “it wouldn’t be hard to work out the problems. It would take time. It would take trade-offs. But we could get somewhere.” Waxman, a California Democrat who served in Congress for 4 decades as a leader on environmental and other issues, said at a 10 June forum in Washington, D.C., that although congressional Republicans and the Trump administration present significant obstacles, he is hopeful about action on climate change. If some Republicans would be willing to seriously negotiate about climate change, “it wouldn’t be hard to work out the problems,” said Waxman. “It would take time. It would take trade-offs. But we could get somewhere.” Waxman, who retired from Congress in 2015, had a prolific legislative career that included leadership on improving the Clean Air Act and on health care, among other issues. The 10 June forum about lessons from the Clean Air Act was sponsored by Resources for the Future and the American Academy of Arts and Sciences and also included other experts who focused on the successes and failures of the Clean Air Act. The former congressman, who currently chairs Waxman Strategies, a Washington, D.C.–based public affairs and strategic communications firm, recalled that the successful 1990 reauthorization of the Clean Air Act benefited from a lot of horse trading with Republicans as well as with Democrats who represented states dependent on coal. Lack of Republican Support for Earlier Climate Legislation However, at the forum, Waxman also recalled his disappointment about the American Clean Energy and Security Act, commonly referred to as the Waxman-Markey bill. That legislation, which was introduced 10 years ago when Waxman was chair of the House Energy and Commerce Committee and Sen. Ed Markey (D-Mass.) was chairman of its Subcommittee on Energy and Environment, passed in the House but died in the Senate. The bill would have established a nationwide greenhouse gas cap-and-trade system with goals to reduce those emissions while also addressing energy efficiency and other issues. “We said to a lot of our colleagues that there is Republican support because so many of these industry groups were supporting it,” Waxman said. However, he added, that didn’t make any difference because Republicans had decided that they didn’t want to give then President Barack Obama a victory on anything. “They united against [Obama’s] stimulus bill even though [former] President George W. Bush had a stimulus bill when the economy went down. They wouldn’t support the Affordable Care Act [ACA]. They wouldn’t support the ability to deal with climate change. They were just against everything,” Waxman said. “When Republicans were against everything, we had to do it by Democratic votes, which made it impossible when we lost one vote, the 60th vote in the Senate.” Waxman recalled hoping that the Senate would just pass something so that a bill could go into conference to work out any differences between a House and Senate bill. However, the legislation never made it through the Senate. “The circumstances were that while we passed the climate change bill in the House, we thought the Senate would pass the ACA early and then we’d have the rest of the time to do the climate bill,” Waxman said. “But the Senate couldn’t pass the ACA until Christmas Eve, 2009, and it left us with no time to do anything on the climate bill.” White House Hurdle Waxman said that President Donald Trump, whom he called “so strange,” is a major hurdle for enacting new climate legislation. “The Republicans in Congress are refusing to stand up to him. They’re doing it very, very reluctantly,” Waxman said. “I would be hard put to imagine that if he were reelected and if the Republicans decide that he’s still their leader because he got reelected, that we are going to get much progress. But I’m hopeful that he will get replaced.” However, even if Trump is defeated in the 2020 presidential election, Waxman cautioned that it won’t be smooth sailing to pass strong legislation. “We’ll have a hard job, but it will tear down the biggest obstacle that we have right now,” he said. Trump “has articulated, and nobody has corrected him, that science doesn’t matter.” “The key is changing the political dynamic, and until that happens all the good and creative ideas in the world won’t make much of a difference.”Waxman said that Trump believes that “this is just a plot from China when they talk about climate change.” However, Waxman said that he sees changes on the horizon in public opinion and politics. “Now when you watch the nightly news, almost every night they talk about a climate disaster, and they talk about climate change as leading to these disasters,” he said, comparing current television newscasts to earlier newscasts that didn’t necessarily make that connection. “The public opinion is clearly changing, and that is going to have an impact on their representatives of both political parties and on the courts,” he said. “The key is changing the political dynamic, and until that happens all the good and creative ideas in the world won’t make much of a difference.” —Randy Showstack (@RandyShowstack), Staff Writer'
A new analysis indicates that the frequency and magnitude of extreme precipitation events are expected to increase as Earth continues to warm.
'The simplest thermodynamic equations make it clear that warmer air can hold more moisture than colder air: The Clausius-Clapeyron equation shows that for every 1°C temperature increase, Earth’s atmosphere can hold 7% more water. The reality of global climate science, however, is often more complicated than the simplest thermodynamic equations. Earth’s atmosphere is not uniform. Its composition is constantly changing, and it’s certainly not heating evenly everywhere—some places are even getting colder. Forecasting the likelihood of extreme precipitation events is therefore more challenging than adding numbers to a model. Still, the historic record, especially since anthropogenic warming took off in the 1900s, can provide insight into how Earth’s atmosphere responds to rapid warming. In a new study, Papalexiou and Montanari use a novel technique to analyze historical data and investigate the likelihood that global warming was driving the frequency and magnitude of extreme precipitation events. The scientists collected their data from the Global Historical Climatology Network–Daily database. This data set includes measurements from approximately 100,000 precipitation stations across the world. For their analysis, the researchers focused on the 1964–2013 period when global warming accelerated. They looked at how many complete years of data were recorded for a given station; then they chose to analyze that number of extreme precipitation events. So if a station provided 45 complete years of data, they analyzed the top 45 most extreme events. The authors argue that this analysis technique represents extreme rainfall events more accurately than simply looking at a series of annual maximum precipitation numbers because in the absence of some external force (such as rising temperatures) it should result in an even distribution. Stations with fewer than 5 complete years of data in each one of the 5 decades studied were excluded from the analysis, and after screening for a variety of other criteria, the researchers were left with a record from 8,730 stations from around the world, mostly clustering in North America, Europe, Russia, China, and Australia. The researchers then constructed a time series for both annual frequency and average magnitude of the extreme rain events for each weather station. For the frequency data, the results were especially pronounced, with the occurrence of extreme precipitation events increasing significantly as time went on. In the last decade of data (2004–2013) the scientists found 7% more extreme precipitation events than they’d expect if no external force were skewing the distribution. The data related to magnitude were less pronounced but also indicated a slight uptick. Additionally, the researchers report they found no strong correlation between increasing frequency and increasing magnitude. Finally, because each weather station is also tied to a geographical location, the researchers were able to analyze where the extra rain was falling, with Eurasia, northern Australia, and the midwestern United States absorbing the bulk of the new moisture. The study suggests that as the planet continues to warm, extreme rainfall events will continue to become an increasingly common part of life for many heavily populated parts of the world. As land managers and policy makers fight to stay ahead of climate change, this type of data will become ever more informative and necessary. ( Water Resources Research, https://doi.org/10.1029/2018WR024067, 2019) —David Shultz, Freelance Writer'
Members of the National Academy of Sciences recently voted that membership in the 156-year-old institution can be revoked in cases of “egregious violations” of its Code of Conduct.
'The National Academy of Sciences, established during Abraham Lincoln’s presidency, has long been an exclusive circle of distinguished scientists. But membership in the institution, previously conferred for life, can now be rescinded. Scientists who violate the organization’s Code of Conduct can be stripped of their membership, the National Academy of Sciences (NAS) announced on 3 June. The change to the organization’s bylaws was approved after its thousands of members were polled, and the result was overwhelmingly in support of the amendment. Membership as a “Major Award” Scientists are elected to the National Academy of Sciences by invitation; fewer than 100 researchers are inducted annually. Members are quick to note the advantages of being part of the select group. “It’s absolutely a benefit for people who get in,” said Donald Turcotte, a geophysicist at the University of California, Davis, who was elected as a member in 1986. “Short of [a Nobel Prize], it’s the major award that somebody can get.” In Turcotte’s case, he says the honor helped him secure a faculty position. Should a scientist’s ethical conduct be considered in addition to his or her scientific prowess? Who decides the severity of the misconduct? Is there a statute of limitations?Recently, there’s been increased scrutiny over how scientific prizes and honors—like membership in the National Academy of Sciences—are awarded. That’s because of growing concerns over misconduct in the sciences. Scientific prize–granting organizations are being faced with important questions: Should a scientist’s ethical conduct be considered in addition to his or her scientific prowess? Who decides the severity of the misconduct? Is there a statute of limitations? The answers to these questions and others aren’t clear. What is clear is that the effects of misconduct, including various forms of harassment, can have far-reaching, long-lasting consequences: Scientists who have been harassed have switched research fields to avoid their harassers and even left academia altogether. “In the Past, There Was No Way of Doing This” Some scientific organizations have already taken a stance on this complicated issue. In September 2017, AGU updated its ethics policy to take a much stronger position against harassment. The organization also requires that candidates for an AGU award, honor, or governance position complete a Professional Conduct Disclosure Form in which individuals must disclose if they have been the “subject of a filed allegation, complaint, investigation, sanction or other legal, civil or institutional proceeding.” Last year, AGU rescinded an award after receiving a formal ethics complaint about the prize winner, Nature reported. The National Academy of Sciences, however, hasn’t had any policies in place to strip scientists of their membership. “In the past, there was no way of doing this,” said Turcotte. But in late April, scientists attending the 156th Annual Meeting of the National Academy of Sciences in Washington, D.C., began setting changes in motion. The policy is “bringing the NAS up to the issues that are being faced today.”At a business session on 30 April, NAS members voted to amend the organization’s bylaws. The vote allowed the 17-member NAS Council to revoke the membership privileges of scientists who violated the Code of Conduct. Citing the “substantive” nature of this amendment, however, the National Academy of Sciences decided the vote would need to be ratified by its full membership. An email was sent to all of the organization’s roughly 2,300 members asking them to cast their ballot through the NAS website. Cathy Whitlock, an Earth scientist at Montana State University in Bozeman, voted in favor of amending the bylaws. “I’m completely supportive of the effort,” said Whitlock, who was elected to the National Academy of Sciences in 2018 and is also a member of AGU. “It’s bringing the NAS up to the issues that are being faced today.” The voting outcome, which closed on 31 May, was a resounding 84% in favor of the amendment. “The amendment passed by a large margin,” Susan Wessler, home secretary of the National Academy of Sciences, announced to members on 3 June. Adhering to the Highest Standards of Professional Conduct This change will potentially affect only a “very, very small number” of NAS members, but it sends a strong message, said Turcotte. Marcia McNutt, the president of the National Academy of Sciences, echoed this sentiment. “This vote is less about cleaning house and more about sending the message that the members of the National Academy of Sciences adhere to the highest standards of professional conduct and are serious about expecting that their colleagues abide by our code,” McNutt told Science . McNutt, a marine geophysicist, was president of AGU from 2000 to 2002. The National Academy of Sciences’ decision is an important one, said Chris McEntee, AGU’s chief executive officer and executive director. “We are pleased to see organizations like the National Academy of Sciences…look at updating their own codes of ethics to address serious issues of harassment, bullying, and discrimination in science.” —Katherine Kornei (@katherinekornei), Freelance Science Journalist'
A new opportunistic sensing strategy could use existing closed-circuit television networks to accurately capture rainfall intensity, despite low-cost equipment and visually complex scenes.
'The same security cameras used on seemingly every busy city block could also capture instantaneous measurements of rainfall intensity: the depth of rain that falls over a given time period. Developed by Jiang et al. , this low-cost approach could help inform flood warnings, climate change research, water resource management, and other hydrologic pursuits. Rain gauges traditionally provide intensity measurements but are often too sparsely spaced for high-resolution data, especially in topographically varied areas like cities. Remote sensing methods such as weather radar are too “big picture” and too indirect to aid real-time flood warnings. Instruments called disdrometers capture instantaneous rainfall intensity but are too pricey for widespread use. The new, alternative strategy uses “opportunistic sensing,” in which novel insights are gleaned from unrelated sources. Recognizing the ubiquity of close-circuit television (CCTV) cameras, the researchers developed an algorithm that separates a CCTV video still into one layer capturing the streaky shapes of falling raindrops and another layer of the raindrop-free background. Image analysis then reveals instantaneous rainfall intensity. The researchers tested their new raindrop identification algorithm in a series of virtual analyses. They found that it outperforms previously developed algorithms in separating raindrops from backgrounds with visual disturbances, such as moving cars and swaying trees. They also tested their overall approach to rainfall intensity measurement in real-world settings during five different rainfall events and found that the approach has satisfactory accuracy over widely varying rainfall intensities. It also has a lower error rate than other camera-based strategies, despite its reliance on lower-quality cameras and testing with real-world scenes that are more complex. The new approach highlights the possibility of using existing CCTV networks to opportunistically measure rainfall intensity at high resolution and low cost. Such observations could help researchers validate climate models and improve understanding of floods caused by intense storms, especially in urban settings. The authors suggest several paths for future research, including fine-tuning the raindrop identification algorithm to capture a wider range of raindrop phenomena, such as splashing. Application of artificial intelligence techniques could also enhance the new approach. The research team is now working with the local meteorological department to implement this technology in Shenzhen, China’s “tech megacity.” ( Water Resources Research , https://doi.org/10.1029/2018WR024480, 2019) —Sarah Stanley, Freelance Writer'
Modeling icebergs as Lagrangian elements held together by numerical bonds provides insights into coupled exchanges of heat, freshwater, and momentum between large icebergs and the ocean.
'Large tabular icebergs that break off ice shelves in Antarctica drift north into the Southern Ocean. Standard ocean models assume that, regardless of its size, an iceberg can be treated as a “passive tracer” that follows the ocean currents that would be predicted in a model which ignored the iceberg. However, a large iceberg modifies the ocean around itself in ways that affect its path and the rate at which it melts. Stern et al.  describe a new model for the ocean, ice shelves, and icebergs that includes the feedbacks between the ocean and the ice as an iceberg breaks away from an ice shelf and begins to drift into the open ocean. Their model shows how the three-dimensional currents that are generated around the iceberg affect melting rates, iceberg drift and rotation, and the transport of water that is trapped under the iceberg. This new approach to modeling icebergs should lead to better predictions of how ice that is lost from the Antarctic Ice Sheet is carried away from the Antarctic coast to influence the Southern Ocean’s stratification, sea ice and ecosystems, and its role in global climate. Citation: Stern, A. A., Adcroft, A., & Sergienko, O. V. . Modeling ice shelf cavities and tabular icebergs using lagrangian elements. Journal of Geophysical Research: Oceans , 124. https://doi.org/10.1029/2018JC014876 —Laurence Padman, Editor, JGR: Oceans'
In the wake of a dire report on global threats to biodiversity, experts explain why the issue is so urgent, not just to the environment and to threatened species but also to people.
'A recent grim report about the fate of biodiversity worldwide states that about 1 million species are threatened with extinction, many within decades. It also found that the global rate of species extinction “is already at least tens to hundreds of times higher than the average rate over the past 10 million years and is accelerating” due to factors including changes in land and sea use, pollution, and climate change. But at a 4 June congressional hearing, Rep. Ami Bera (D-Calif.) wanted to know how he could explain to his constituents why this report by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) is, as he put it, “incredibly important.” At the hearing, conducted by the House Committee on Science, Space, and Technology, committee member Bera asked the expert witnesses to give it their best shot. “When we destroy nature, we really undermine all of those life-support systems on which we depend.”“From the very food we eat to the way we define ourselves and our sense of place, nature is an incredibly integral part of all of our lives. And when we destroy nature, we really undermine all of those life-support systems on which we depend,” responded Kate Brauman, coordinating lead author for the IPBES Global Assessment and lead scientist with the Global Water Initiative at the University of Minnesota’s Institute on the Environment. “Biodiversity fundamentally is not just an environmental issue,” IPBES immediate past chair Robert Watson weighed in. “Nature has economic value which we should take account of in our accounting systems. It also has development value: food, water, energy, security, human health. It is also a moral issue: We shouldn’t destroy nature. And it’s a social issue, as you’ve heard that the most disadvantaged people, poor people, are most adversely affected. So there are multiple reasons we should care about both climate change and biodiversity.” “Totally Day and Night” For Watson, the difference between this hearing and an earlier, divisive 22 May hearing conducted by the House Committee on Natural Resources was “totally day and night.” The 4 June hearing was “incredibly constructive,” Watson told Eos , “where people are truly trying to understand what are the issues associated with the loss of biodiversity [and] what are some of the solutions. I would hope that all hearings would be like this one.” “You have to bear in mind that there are different cultures on different committees.”The earlier hearing, Watson noted, “was very destructive. It was not a good conversation about facts and knowledge and evidence.” “You have to bear in mind that there are different cultures on different committees,” Rep. Frank Lucas (R-Okla.), the ranking member on the science committee, told Eos . He said that the science and agriculture committees “have a more collegial perspective, generally. There are other committees—government oversight, judiciary—where they like to make lots of noise. [Natural] resources falls somewhere in the middle.” Lucas added that the science committee hearing was an example of where he and committee chair Rep. Eddie Bernice Johnson (D-Texas) want the committee to go. “This was very thoughtful. You had a diversity of perspectives focused on how to make a difference. The members were engaged. This is the way hearings are supposed to work,” he said. Findings “Too Stark to Ignore” Johnson, in her opening statement, called the IPBES findings “too stark to ignore.” “Much of the reporting on the Global Assessment has focused on the devastating finding that almost 1 million species could potentially go extinct in the next few decades,” she continued. “But we would be remiss if we did not discuss what else this report lays out, especially its recommendations for potential solutions and pathways to addressing biodiversity loss.” “If the oceans had not been the Earth’s punching bag to take this heat, then the average temperature outside this room today would be 122°F.”Johnson told Eos that she expects that the committee will continue to look into the report “and see what, if any, legislative approaches we can achieve” to reduce the threats to biodiversity. Some of the most urgent threats to biodiversity are taking place in coral reefs, testified James Porter, professor emeritus of ecology at the University of Georgia’s Odum School of Ecology. Porter said that climate change is the key driver of diversity loss in the oceans. “Of the warming heat that has been generated in the last 50 years, only 7% of that is in the air. The remaining 93% of the heat is in the oceans,” Porter said. “The oceans have absorbed this heat. We know this because we have indeed measured it. If the oceans had not been the Earth’s punching bag to take this heat, then the average temperature outside this room today would be 122°F. That is the physics of what we are dealing with.” Porter added that if coral reefs are destroyed, people who depend on them as a source of income, protein, and livelihood may become climate refugees. Not All Gloom and Doom Porter and other witnesses also stressed the need to look for solutions. The IPBES report essentially confirms what we have long known: Humans have made things very tough for nature,” testified Steven Monfort, director of the Smithsonian’s National Zoo and Conservation Biology Institute. However, he added, “if we just bombard the public with messages of gloom and doom, absent any focus on solutions, we risk fostering a sense that nothing anyone does is going to make a difference.” Jeff Goodwin, conservation stewardship lead and agricultural consultant with the Noble Research Institute in Ardmore, Okla., was the sole Republican witness at the hearing. He noted one potential solution: a movement in the agricultural industry that he said is returning biodiversity to the land. Goodwin said that the movement “was not borne out of legislation or regulatory requirement. It was borne out of the recognition by innovative producers who understood [that] the adoption of ecologically and economically sustainable principles would enable them to remain on the land producing the food and fiber needed for an ever expanding population.” Brauman testified that humanity’s “transformation of nature has been critical for both human nutrition and livelihoods. But we also must be clear-eyed about the impact. We have transformed the globe.” Despite that transformation, however, she said that there are pathways forward. “The headlines are dire, but the report is actually not that dire,” Brauman told Eos . “What we see is that there are many futures where there is lots of possibility. We will need to make change, but it’s absolutely doable.” —Randy Showstack (@RandyShowstack), Staff Writer'
Nearly 10 years after the introduction of the ambitious Waxman-Markey climate change bill, experts assess the chances of climate legislation.
'This time could be different. That’s what former Rep. Henry Waxman hopes. Ten years ago this month, he and Sen. Ed Markey (D-Mass.), who was then a U.S. representative from southern California, introduced far-reaching legislation to curb climate change. The American Clean Energy and Security Act (ACES), commonly referred to as the Waxman-Markey bill, would have established a nationwide greenhouse gas cap-and-trade system with goals to reduce those emissions while also addressing energy efficiency and other issues. The bill passed in the House with a vote of 219–212 on 26 June 2009, but it died in the Senate on 22 July 2010, having failed to win enough votes because of an effective lobbying effort by special interests, among other reasons. But the landscape has changed dramatically since then, and the chance for significant climate action in Congress may be better soon, perhaps after the upcoming presidential election if a climate-friendly president is elected, Waxman told Eos . “The public is going to demand action,” said Waxman, who in 2009 was chair of the House Energy and Commerce Committee. “The public has been seeing constant examples of the harm that is coming from climate change.” “The public is more attuned to what’s happening and is not going to accept the view that there’s no problem,” added Waxman, who currently chairs Waxman Strategies, a Washington, D.C.–based public affairs and strategic communications firm. “They are going to see the reality in connecting the scientific statements about climate change with the experience of climate change. It used to be that Republicans and others thought we wouldn’t see any problems for many, many decades, but we’re seeing the effects of climate change right now.” A Riper Time for Action? Other politicians and experts also say that the time is riper now for action, because of the increased urgency about climate change that has been highlighted in recent scientific reports and because of increased awareness and activism about the issue. “The difference between 2009 and ’10 and today is the movement that has now been built,” Markey said at the 7 February 2019 press briefing outside the U.S. Capitol Building, where he and Rep. Alexandria Ocasio-Cortez (D-N.Y.) introduced the sweeping Green New Deal resolution, an ambitious proposal to achieve net-zero greenhouse gas emissions by 2050, promote climate justice, and create jobs, among other goals. In 2009, Markey was chairman of the House Energy and Commerce Subcommittee on Energy and Environment. Climate change “is now a voting issue across the country,” Markey said. “The green generation has risen up, and they are saying that they want this issue solved, and they want the people who work in this building and occupy the White House to solve this problem. So this is going to enter the 2020 election cycle as one of the top two or three issues for every candidate on both sides for them to have to answer.” He and others highlighted another distinction between then and now. The year 2009 was when the libertarian Koch brothers and others “started to pour their millions into trying to create a climate where people did not believe in climate science,” Markey said. “We now have the troops. We now have the money. We’re ready to fight. OK. And so the difference between 2009 and ’10 and today is we now have our army as well.” That army of activists and concerned citizens, along with scientific reports by the Intergovernmental Panel on Climate Change and others, and the increasing evidence of climate change have encouraged many Democratic presidential candidates to support the Green New Deal or other strong actions on climate change. These candidates include current frontrunners former vice president Joe Biden; Sen. Bernie Sanders (I-Vt.); Sen. Elizabeth Warren (D-Mass.); South Bend, Ind., mayor Pete Buttigieg; and Sen. Kamala Harris (D-Calif.). Another candidate, Washington governor Jay Inslee, calls climate change the country’s number one issue. The Democratic National Committee, however, reportedly has rejected a call for a presidential primary debate to focus on climate change. Any Possibilities in Congress This Session? Rep. Jared Huffman (D-Calif.) told Eos that the Waxman-Markey bill stands as “the high water mark for climate leadership in the Congress,” but he is hopeful that even in the current political climate, there could be action in Congress.“Just catching up to where we were then feels like a Herculean task given the fossil fuel industries’ efforts.” “Just catching up to where we were then feels like a Herculean task given the fossil fuel industries’ efforts and the way they have punished Republicans who did support climate leadership in the Waxman-Markey bill,” he said. However, Huffman, chair of the House Natural Resources Subcommittee on Water, Oceans, and Wildlife, added, “I have faith that even the most shriveled heart of my Republican colleagues at some point will have to think about future generations.” Some analysts won’t totally write off the possibility of minor legislation related to climate change reaching the president’s desk for approval this Congress, despite current resistance by the Senate Republican leadership and the Trump administration’s attacks on climate science. Indeed, a lot of climate-related legislation has been introduced in the Democratically controlled House, which has held numerous hearings about climate change. And some legislation even has passed the House, including the Climate Action Now Act, which directs President Donald Trump to honor the nation’s commitments under the 2015 Paris climate agreement, and four bills dealing with ocean acidification. However, the Climate Action Now bill likely has little chance for passage in the Senate, and the same fate may await some of the other legislation as well. Sara Chieffo, vice president of government affairs with the League of Conservation Voters (LCV), told Eos that she has not given up on the possibility of there being moderate progress on climate change legislation during the current Congress, but she thinks that passing major legislation will need to wait for a more environment friendly Senate and White House. “Given the scope and scale of the crisis and the support from pro-environment members of Congress, we are going to try to make progress where we can,” she said, whether it is, for instance, within appropriations legislation, a potential tax vehicle, or infrastructure or defense bills.“If you are asking, is anything transformative possible with President Trump in the White House? Our answer is no.” “There is no reason we shouldn’t be making small progress through those vehicles,” added Chieffo, who joined LCV just 3 weeks before the Waxman-Markey bill was marked up in the House Energy and Commerce Committee,. “But if you are asking, ‘Is anything transformative possible with President Trump in the White House?’ our answer is no.” David Doniger, senior strategic director for the Natural Resources Defense Council’s (NRDC) Climate and Clean Energy Program, largely agreed with that assessment. “Nothing constructive can occur during this term with this administration not playing any positive role, playing only negative roles,” he told Eos . However, Doniger, who followed the Waxman-Markey bill closely for NRDC, said that there could be substantive and constructive steps forward, even now, in appropriations bills and perhaps in transportation and disaster relief, planning, and preparation legislation. In addition, he said that now is a time “to continue to build and refine public support” for action on climate change and to elaborate on specific legislative proposals that could be ready to move forward perhaps in a more favorable next congressional session. Doniger cautioned, though, that a so-called innovation agenda that some Republicans are pushing, with a focus on potential technological fixes, “is just not enough by itself” to solve the climate change problem. “We need to see a commitment and understanding [from them] that we really do have to reach net-zero emissions by the middle of the century,” Doniger said. “That has to be the yardstick for measuring the effectiveness of policies that a political office holder advocates.” Going Big? “We need to think differently about how to get climate action through Congress,” said Jeremy Symons, who was senior vice president for programs at the National Wildlife Federation during the Waxman-Markey effort. “We need to go big in Congress but not put all our eggs in one legislative basket.”“Climate measures big and modest should be incorporated into all parts of Congress’s legislative agenda,” Symons, now the principal at Symons Public Affairs, a consulting firm supporting climate action, told Eos . “After all, the entire climate is changing, and tackling climate will require investment and updated regulations across all parts of government operations. We need to go big in Congress, but not put all our eggs in one legislative basket.” The Green New Deal is one attempt to go big. Waxman commented that although a lot of the details of that resolution, including the funding for it, have not been fleshed out, he is encouraged by the effort to bring greater urgency to the climate change issue. Speaking about the resolution’s sponsors, Waxman said, “I’m proud of the fact that they have taken up this fight and they are pushing hard. I find that encouraging because it would be a shame just to withdraw from this battle, when we’ve got to prepare ideas that we need to turn to, if not now, [then] when we have the opportunity to pass legislation and use existing laws.” Another attempt at going big, and perhaps being a successful next major step following the Waxman-Markey bill is the Energy Innovation and Carbon Dividend Act of 2019. It would impose a fee on the carbon content of fuels and on products “derived from those fuels that will be used so as to emit greenhouse gases into the atmosphere,” with the fee providing dividend payments to U.S. citizens or lawful residents. Mark Reynolds, executive director of the Citizens’ Climate Lobby (CCL), which supports the legislation, told Eos that although the bill may not pass this Congress, it sets a marker. The current version “lays the groundwork for a simple transparent bill to be the next major climate bill introduced,” he said, noting that CCL tries to work in a bipartisan manner on climate issues. “If we can establish that this is the bipartisan approach to the problem, then I think that’s a huge win for everybody working on this issue.” Reynolds told Eos that a related bipartisan effort, the congressional Climate Solutions Caucus, is in the process of being reconstituted following the 2019 elections. He said that Rep. Francis Rooney (R-Fla.) will be the new Republican cochair of the caucus, with Rep. Ted Deutch (D-Fla.) continuing on as the Democratic cochair. New Changes and Familiar Opposition The political landscape has changed in other ways since Waxman-Markey. Antonia Herzog, who was a federal climate policy analyst with NRDC when the bill was being considered, told Eos that, for instance, there has been “a lot of great stuff happening in the states and at the local levels” over the past decade to deal with climate change. However, she said she wishes that more action had already taken place. “Every single year is a year that has been lost since it became obvious that [climate change] is a problem,” said Herzog, who currently is the climate and energy program manager for Physicians for Social Responsibility. LCV’s Chieffo added that the clean energy economy is far more mature now than it was a decade ago. “Would we be better off if we had already been implementing climate solutions at the federal level that Congress had passed 10 years ago? Certainly. But are we starting out from zero? The answer is no,” she said. In addition, there has been significant activity in the private sector. For instance, the We Are Still In coalition counts about 3,800 organizations in the United States—including businesses as well as states and cities—committed to meeting the Paris goals. In addition, former New York Mayor Michael Bloomberg announced today, 7 June, a $500 million Beyond Carbon campaign to tackle climate change. One thing that hasn’t changed much in the past decade is the opposition, say a number of experts. “The climate obstruction lobby has a dollar-driven death grip on Republican politicians. “The number one barrier to action in 2009 is the same barrier we face in 2019. The fossil lobby has teamed up with some deep-pocketed conservative donors in order to paralyze government action from the beltway to state ballot initiatives,” said Symons. “It’s far easier to scare people and block government action than it is to bring about real change. I call this the climate obstruction lobby. The climate obstruction lobby has a dollar-driven death grip on Republican politicians.” That lobbying “lowered the probability of enacting the Waxman-Markey bill by 13 percentage points,” according to a paper, “The Social Cost of Lobbying over Climate Policy,” published in the June issue of Nature Climate Change . “There is going to be a ton of oil and gas money fighting us, that’s for sure. But I don’t think it is guaranteed to have the same influence as 10 years ago,” said Doninger. He said that’s in part because the coal industry is not the economic or political force that it had been and because other energy industries, including wind, solar, and even nuclear, are asserting themselves in the economy and in politics “in ways you didn’t see 10 years or more ago.” Theda Skocpol, professor of government and sociology at Harvard University, told Eos that although the fossil fuel industry is a significant driver of climate denialism, “the real force on the right is the Koch network.” That network “is not just the brothers. It’s 400 to 500 ultraconservatives who organize to take over the policy making of the Republican Party, and they are very successful,” said Skocpol, author of a 2013 analysis of the defeat of the Waxman-Markey bill, “Naming the Problem: What It Will Take to Counter Extremism and Engage Americans in the Fight Against Global Warming.” “This is just one issue of a number where they’ve weighed in and changed the Republican policy making on the economy, the role of government in the economy in the states and the federal government. But this is absolutely a core area. So they both reward Republicans who hew the line they want, and they punish those who do not. You don’t find very many Republicans who are actually in office or who are running for office who are prepared to go along with much of anything.” She added, “Republican officeholders and elites are just as locked into blocking action as they have been for a decade. And Donald Trump is definitely the denier in chief.” Hope for a Better Outcome Despite the defeat of the Waxman-Markey bill and the continued opposition to advance and enact climate change legislation at the federal level, experts say that there is renewed hope for incremental climate change steps now and major measures perhaps as soon as the next Congress. They also are encouraged by nonfederal progress over the past decade, the focus on climate change in the current Congress, and the heightened awareness and advocacy about climate change in light of the increasing urgency of the issue. “The problem is going to be more and more on people’s minds as they see tornadoes and storms and droughts and all the consequences of what the scientists have been predicting from climate change,” Waxman told Eos . “They are going to demand action, and they are going to, in a democracy, turn away from those who say that there is no problem, because the truth is being driven home by people’s experiences.” —Randy Showstack (@RandyShowstack), Staff Writer'
Attracting and retaining women in the sciences require action on all fronts: stopping outright harassment, changing institutional cultures, and ensuring that women are included, recognized, and heard.
'To succeed in science, women must overcome subtle biases that favor men as well as a culture of overt sexual harassment. These barriers to success result in the underrepresentation of women in science: In the United States, women receive 50% of geoscience Ph.D.’s but represent only 20% of geoscience faculty positions. The systemic underrepresentation of women in science fosters a culture of sexual harassment, which in turn discourages women from careers in science and perpetuates underrepresentation. For people who claim more than one marginalized identity, the multiplicative effects of these barriers can be especially severe.Although calls have been made for senior scientists to address sexual harassment and break the cycle, a broader cultural shift is required to reach gender equity in science. Ultimately, the majority group (i.e., men, specifically, white men) must step up and share the burden of diversity, equity, and inclusion efforts if we are to succeed in making science diverse, equitable, and inclusive. We focus on binary gender here, but other underrepresented groups in the geosciences face barriers on the basis of their ethnicity, nonbinary gender, sexual orientation, economic status, disability, geography, or religion, among other factors. For people who claim more than one marginalized identity, the multiplicative effects of these barriers can be especially severe. Many of the strategies outlined here can be generalized to improve the diversity, equity, and inclusion of all underrepresented groups in science. Here we present an eight-point subset of the many available resources and concrete strategies for effecting a cultural transformation. The AGU Ethics and Equity Center, which launched earlier this year, provides further resources to educate; to promote and ensure responsible scientific conduct; and to establish tools, practices, and data for organizations to foster a positive work climate in science. 1. Stop Harassing Women Most women in science experience sexual harassment at some point during their career, most of it perpetrated by men. In the geosciences, field research environments, which can isolate victims from reporting systems and support networks, amplify the frequency and severity of sexual harassment. One reason for the prevalence of sexual harassment in science may be the harasser’s ignorance of which behaviors are merely inappropriate and which ones constitute sexual harassment, as defined by a recent report on sexual harassment of women by the National Academies of Sciences, Engineering, and Medicine (NASEM). It is widely recognized that sexual harassment includes unwanted sexual touching (unwelcome physical sexual advances, which can include assault) and sexual coercion (favorable professional or educational treatment that is conditioned on sexual activity). However, the vast majority of sexual harassment consists of verbal, unwanted sexual attention or gender harassment (verbal and nonverbal behaviors that convey hostility, objectification, exclusion, or second-class status toward women). All forms of sexual harassment have quantifiable negative consequences for victims. These consequences include eroding their sense of security in the workplace, slowing their productivity, and causing them to skip professional meetings where they do not feel safe. Men in the scientific community must confront the reality that many of us have sexually harassed women and that the harassment must stop. 2. Listen to Women Effective listening requires paying attention to, understanding, not interrupting, believing, responding to, and remembering what is being said.Listening to the scientific and personal experiences of women in science is paramount to achieving gender diversity and equity in science. Effective listening requires paying attention to, understanding, not interrupting, believing, responding to, and remembering what is being said. The simple act of listening to women’s science promotes their work, while acknowledging the barriers they face validates their experiences and improves the institutional climate. 3. Be an Active Bystander In addition to not harassing women, it is our responsibility to be active bystanders. When active bystanders suspect or witness potential or ongoing sexual harassment, they step in to diffuse the situation and support the targeted party. Active bystanders always prioritize the safety of the targeted party over punishing the harasser. Active bystanders should know the resources relevant to victims of sexual harassment. For example, they should have the number 1-800-656-HOPE (4673), the National Sexual Assault Telephone Hotline, in their phones. They should also be able to provide information to their institution’s ombuds’ office, which is an independent and confidential party that helps victims of harassment resolve disputes within their institution. Leaders of scientific institutions should require face-to-face active bystander training because online sexual harassment trainings have been shown to backfire and may actually lead to increased workplace harassment. Men should participate in these active bystander trainings when offered, such as at the recent AGU Fall Meeting 2018. How might an active bystander respond to an incident at a scientific meeting? Here are two hypothetical examples: A male conference attendee aggressively questions a woman speaker and repeatedly dismisses her answers. An active bystander on the session panel might interrupt the questioner and suggest moving on to questions from other attendees. A conference attendee is holding the arm of a visibly uncomfortable woman who is giving a poster presentation. An active bystander might diffuse the situation by introducing themselves to the poster presenter with a handshake—giving the woman presenting an opportunity to free her arm from the harasser—and standing by to listen to the remainder of her presentation. 4. Implement Policies That Support Victims of Sexual Harassment The responsibility of implementing policies that support women lies with those who hold most of the power, namely, male institutional leaders. Following the recommendations of the NASEM report Sexual Harassment of Women , leaders in science should implement the following concrete policies (the report contains a more complete list): Leaders of scientific departments, institutions, and organizations must make it clear that sexual harassment is a form of scientific misconduct.Leaders of scientific departments, institutions, and organizations must make it clear that sexual harassment is a form of scientific misconduct that carries clear and appropriate negative consequences for proven harassers. When a victim files a harassment claim, the priority of the institution should be to ensure that the victim can safely continue their work. Institutions need to consider the confidentiality of the target while also directing that person toward systems of support for victims of harassment. Sexual harassment policies should be clear, accessible, and consistent. They should address all forms of sexual harassment, including gender discrimination. Anonymized annual reports should be available to the entire community, detailing statistics of recent and ongoing sexual harassment investigations, including any disciplinary actions taken. Academic institutions have a poor track record when it comes to punishing sexual harassers, especially when the harassers are faculty members. Disciplinary consequences should be progressive: They should correspond to the frequency and severity of the harassment. For example, disciplinary consequences might escalate from requiring counseling to reductions in pay to dismissal. Progressive consequences have the cobenefits of appropriately punishing harassers and reducing the fear of retaliation for victims. Funding agencies and professional organizations should rescind existing funding and awards from proven harassers. 5. Evaluate Your Personal Biases Women in science are disenfranchised not only by sexual harassment but also by structural and implicit biases. For example, science faculty (irrespective of gender) view male students as more competent than equally qualified female students. Similarly, recommendation letters for postdoctoral fellowships in geoscience display significant gender differences that favor male applicants. The first step to eliminating implicit biases is to recognize and quantify them. Women already count how well women are represented in conference sessions, panels, papers, and committees. Men should also evaluate the gender balance of their collaborators and departments and strive for equal representation. Men should consult existing resources for avoiding bias. 6. Promote Women Scientists and Their Work Combating implicit biases against women in science requires an explicit effort to promote women scientists and their work.Combating implicit biases against women in science requires an explicit effort to promote women scientists and their work. When writing papers, cite women. If you can think of only a few women authors to cite, look at those papers and consider the women authors they cite—you may discover relevant papers you overlooked. When planning invited departmental talks, consider the gender balance of invited speakers and strive for equal representation. If you are struggling to adequately represent women when organizing a panel, searching for a keynote speaker, or covering a recent paper for a media outlet, consider consulting women colleagues or resources such as the Request a Woman Scientist list, compiled by the group 500 Women Scientists. This list contains thousands of women scientists and is sortable by scientific field and level of expertise. 7. Incentivize and Support Inclusion Efforts Women take on the majority of diversity, equity, and inclusion efforts in science at the expense of teaching and research, often without reward. Institutions should recognize, reward, and incentivize diversity, equity, and inclusion efforts. Such efforts include creating a departmental award for diversity, equity, and inclusion efforts; requiring a diversity statement in faculty applications; and recognizing diversity, equity, and inclusion efforts as positive contributions in promotion packages. Institutions should encourage men to participate in diversity, equity, and inclusion efforts. Men can be trained as equity advisers to combat implicit bias and advocate for underrepresented groups, for example. Programs like STEM Equity Achievement (SEA) Change provide metrics to evaluate institutional efforts to improve diversity, equity, and inclusion. 8. Hire Women Faculty and Nominate Women for Awards and Leadership Positions Women are particularly underrepresented in leadership positions in science. They represent disproportionately few geoscience faculty members; science, technology, engineering, and mathematics (STEM) department heads; and AGU Fellows and awardees. Institutions should implement policies that encourage the nomination and hiring of women. Such policies include explicit reminders to nominate women for awards; support for existing efforts to nominate scientists from underrepresented groups; and hiring clusters of scientists from underrepresented groups at the same time, a practice that can dramatically improve faculty diversity and institutional climate. As you can see, promoting diversity in the sciences requires all kinds of efforts, large and small. Individuals can make some of these changes by being observant of their own attitudes and actions and by stepping in to help when they see an opportunity to do so. Other changes require institutional leaders to enact policies and offer training and resources that promote fair treatment. Individuals can influence these larger efforts by advocating for change and by stepping forward to assist with institutional-level efforts. —Henri Drake (firstname.lastname@example.org), Massachusetts Institute of Technology/Woods Hole Oceanographic Institution Joint Program in Oceanography, Cambridge, Mass.'
Six years of acoustic recordings detect seasonal shifts in blue whale vocalizations that correlate with the presence of icebergs, a primary source of ambient ocean noise in the southern Indian Ocean.
'Whales make a wide variety of sounds, including clicks and vocalizations, to interpret their surroundings and communicate with other members of their pods. Since the emergence of acoustic monitoring technology several decades ago, researchers have noted that blue whale songs have steadily decreased in pitch, but the cause of this phenomenon, including whether or not humans may shoulder some of the blame, remains uncertain. To extend the geographic range of whale call observations, Leroy et al. studied acoustic recordings collected at six sites across the southern Indian Ocean. The authors used Deformation of the Ocean Lithosphere using Hydrophones (DEFLO-HYDRO) and Observatory of Hydroacousticity from SISmicity and Biodiversity in the Indian Ocean (OHA-SIS-BIO) hydrophone array data sets, which collectively represent a nearly continuous record from 2010 to 2015, and captured more than 1 million Antarctic blue whale calls, as well as vocalizations from fin whales and three acoustically distinct pygmy blue whale populations: Australian, Sri Lankan, and Madagascan. The results indicate the vocalization pitch has steadily decreased in all five whale populations by a few tenths of 1 hertz per year. This finding is consistent with previous studies of Antarctic blue whales but the first documented occurrence of this phenomenon in both fin and Madagascan pygmy blue whales. The authors argue that this trend could reflect increasing whale populations, differences in the ocean’s acoustic properties due to changing environmental factors like ocean acidification, or a combination of both. Because of the study’s long duration and broad spatial distribution, the team was also able to detect seasonal, up-and-down shifts in the pitch of Antarctic blue whale calls superimposed upon this interannual trend. These intra-annual fluctuations peak during the austral summer and correlate with seasonal fluctuations in ocean noise, particularly the low-frequency sounds emitted by drifting icebergs, a primary source of ambient noise in the southern Indian Ocean. The change in call pitch is believed to be linked to a change in call intensity in response to the seasonal variation of noise level. The authors’ evidence for both seasonal and interannual changes in the pitch of whale vocalizations and their suggestion that these phenomena may result from different drivers are likely to be of broad interest to the scientific community. This study clearly demonstrates the value of obtaining widespread and long-term acoustic recordings of cetacean calls to determine why they are changing and the importance of interdisciplinary collaboration to effectively collect and process massive data sets and interpret the results. ( Journal of Geophysical Research: Oceans , https://doi.org/10.1029/2018JC014352, 2018) —Terri Cook, Freelance Writer'