Google Timelapse lets you see the effects of climate change since 1984, including the rapidly retreating Exit Glacier in Alaska.
Archive for the ‘Satellite’ Category
As Lake Chad Shrinks Rapidly, Space Technology And Drones Are Needed To fight Africa’s Droughts
February 26th, 2017
Google Earth Update Shows How Climate Change Has Morphed Our Planet
November 30th, 2016
Using Satellites To Help Cut Down Illegal Fishing
September 15th, 2016
How Satellites and Big Data Can Help to Save the Oceans
May 17th, 2016
Can Satellites Help Save The World’s Tigers From Extinction?
April 21st, 2016
To Take Earth’s Pulse, You Have To Fly High
October 25th, 2015
As Lake Chad Shrinks Rapidly, Space Technology And Drones Are Needed To fight Africa’s Droughts
February 26th, 2017
Via Quartz, a look at how emerging technological opportunities for improving environmental monitoring and the need to act in time could help manage crisis like Lake Chad:
Nigerian and Chadian officials are seeking $50 billion for a major water diversion project to replenish Lake Chad. This is nearly twice the annual GDP of Uganda. But it’s understandable, the lake has shrunk by nearly 90% between 1963 and today.
The plan involves diverting water from the Oubangi River in Central Africa to replenish the lake. It is estimated that the feasibility study alone would cost nearly $15 million. The proposed project would also provide irrigation, energy, and transportation infrastructure aimed at stimulating economic development.
With the election of Chadian foreign minister Moussa Faki Mahamat as chairperson of the African Union Commission, the project and the larger security concerns will remain a priority for the organization as well as for diplomatic interactions with other regions of the world.
Lake Chad offers a grim cautionary tale of how lessons from chronic drought might inform our anticipation of the potential impact of climate change in many parts of Africa. It shows the close interconnections between ecological change, security, and development. But it also points to emerging technological opportunities for improving environmental monitoring and the need to act in time.
The lake straddles the borders of Cameroon, Chad, and Nigeria. This is the same region that is ravaged by the excesses of Boko Haram. It provides water for nearly 30 million people in the semi-arid Sahel region. Its overall basin is the largest closed drainage basin in the world covering 2.5 million square km, or about 8% of the African continent.
The prolonged Sahel drought from the late 1960s to the early 1980s reduced water flow into the lake. The drought, combined with population growth, pushed people in the catchment areas to expand irrigation. This further undercut the flow of water into the lake.
In 1972, the lake split into two, and was separated by a 40 km barrier. The southern lake is shallower and therefore more susceptible to evaporation. To restore the lake level, enough water would need to flow into the southern lake to overflow the barrier and replenish the northern lake. But this has been compromised by drought and irrigation. Simulation studies have shown that the failure of Lake Chad to merge back into a single water body following wetter periods in the 1990s resulted from irrigation. Without irrigation the lake would have probably merged in 1999, and again in 2004.
Lake Victoria’s challenge
The case of Lake Chad is too dramatic to contemplate. But other major water bodies such as Lake Victoria are vulnerable to similar, if not equivalent, impacts. Nearly 80% of the replenishment of Lake Victoria comes from rainfall, which feeds thousands of streams. The lake itself is relatively shallow, averaging 40 meters deep. A prolonged drought could affect large parts of the shoreline, destroying fish breeding areas and agriculture. This would put the lives of millions of people at risk.
Consequences of a receding shoreline due to prolonged drought is unknown. But it would be foolhardy to wait and see. Some people would turn to irrigation, especially on the Kenyan side of the lake, which has the largest number of rivers flowing into it. This would reduce the inflow of water into the lake. Considerable water and land use conflicts would ensue, making them national security challenges. The ramifications would extend to East Africa’s relations with the Nile basin countries, especially Egypt.
Little is known of the consequences of even modest receding of the shoreline due to prolonged drought. But it would be foolhardy to wait and see. The first step in addressing the problem is to conduct real time monitoring of ecological trends in the region. One of the most effective tools available today is satellite technology.
African countries are only starting to explore the use of space technology. Climate change and regional ecological disruptions are already rendering historical maps and geographical data useless. Traditional knowledge is no longer an effective guide for environmental management in light of climate change. Policymakers need a fresh start using modern technologies.
Part of the slow adoption of satellite technology is the perception that space technology is too expensive. The popular and false image of the technology is derived from the last century, when the space programs were too expensive for emerging countries.
This perception has persisted despite dramatically falling costs of developing such programs. African countries can now establish viable space programs with about $300 million. The costs could be shared by neighboring countries. The East African Community, for example, could have one regional space program instead five separate ones.
More countries around the world are now focusing on small satellites, which are easier to build and launch in modular constellations. This is also making it possible for students in South Africa to participate in the design of small satellites and the accompanying scientific experiments.
The other major concern is that the few space initiatives that exist in Africa focus more on turnkey projects. Instead, they should stress building the requisite human capacity needed to rise up the space ladder. The best place to build such capacity is in universities, not in secretive departments in government ministries.
The lifespan of a satellite is about 10 years. Countries that do not invest in continuous training quickly see their ground facilities rendered obsolete by technological change. A space program only functions effectively when it is supported by a strong human resource foundation on the ground.
The future of environmental monitoring is being transformed by the increased use emerging technologies such as civilian drones. Climate change offers Africa yet another reason to leverage the drones to complement satellite technology. Increasing the installation of weather stations across Africa would provide additional support for environmental monitoring. According to Gro Intelligence, the land mass of sub-Saharan Africa is 35 times that of Texas. Yet the two have nearly the same number of weather stations.
The long-term contribution of such efforts lies in building strong institutions of higher learning attached to major infrastructure projects. Such universities can then work with networks of technical institutes and high schools to broaden the base for competence in environmental management.
Investments in human resource development, especially in the engineering fields, will help African countries reduce the maintenance costs of infrastructure projects. Given the magnitude of the financial outlays needed for climate change abatement projects, the continent needs low-cost ways of providing evidence-based advice for the design, implementation and maintenance of infrastructure investments. Ways to do this include expanding the engineering divisions of African scientific academies as well as creating dedicated academies of engineering.
The specter of climate change will continue to haunt Africa. But it also offers new opportunities for tapping into emerging technologies for environmental monitoring to address improve development planning and identify emerging security challenges. Such anticipatory work might give the continent the knowledge needed to respond in time to ecological disasters.
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Read More »Google Earth Update Shows How Climate Change Has Morphed Our Planet
November 30th, 2016
Via Popular Science, a report on how a recent Google Earth update shows how climate change has morphed our planet:
In 2013, Google released Google Earth Timelapse, an interactive viewer that lets users see satellite images of Earth from 1984 to the present, giving a rapid timelapse look at how human development and climate change have shaped our planet. Also in 2013, Popular Science reported that the scientific consensus surrounding human-driven climate change was stronger than ever. With Google’s new update to Timelapse, users can see the effects of global climate change even more sharply, including melting glaciers, rising sea levels, and receding forests.
With more satellite data driving this update, viewers can watch the effects of climate change, such as Exit Glacier in Alaska’s Kenai Peninsula rapidly receding over the past three decades. According to a news release from Google, this update uses “four additional years of imagery, petabytes of new data, and a sharper view of the Earth from 1984 to 2016.” This means it’s easier for users to not only see the effects of climate change, but also the effects of rapid human population growth.
The east African nation of Ethiopia has experienced massive deforestation throughout the past few decades, much of it for agriculture to feed a rapidly growing population. Though government programs to encourage sustainable farming practices have helped slow the pace of deforestation, you can see on this timelapse map how much of the country’s green has turned brown.Other environmental changes, such as sea level rise, are less reversible, but still profound.
One of the places in the United States most affected by sea level rise is Dorchester County, Maryland. As you can see in this timelapse over the past 30 years, the salt marshes in this coastal county have become more and more submerged, which puts communities and the seafood industry at risk.Other coastal communities face similar challenges in the face of a changing world.
This map of the Mississippi River Delta, at Louisiana’s coast, shows how small islands form and disappear over the years. While this process has been ongoing for thousands of years, human communities make these natural shifts more dangerous. The low-lying communities of the Delta region were hit hard by Hurricane Katrina, and another major storm could be even riskier in coming years.Coastal areas aren’t the only places being affected by climate change, though.
Lake McConaughy in Keith County, Nebraska, lies within the northern extent of the Ogallala Aquifer. This shallow water table, which supplies nearly a third of the United States’ irrigation water, has been put under increasing strainsince the middle of the twentieth century, as midwestern farmers have contended with drought to meet ever-increasing demands for their produce.These timelapses may paint a less-than-rosy picture, but remember: You can also just play around with Timelapse to see how your hometown has changed throughout your lifetime.
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Read More »Using Satellites To Help Cut Down Illegal Fishing
September 15th, 2016
Via the Christian Science Monitor, an article on a new approach to monitor waters for illegal fishing:
Environmentalists hope a new satellite service that scans the earth’s seas from space in search of illegal fishing activity can act as a watchdog service, holding those who overfish or intrude on protected areas accountable for the adverse effects of their actions.
The Google-powered technology, which has been named Global Fishing Watch, monitors more than 35,000 commercial fishing vessels using public broadcast data and is available to anyone with an internet connection, The Washington Post reported. Such information allows governments, journalists, and citizens to track the movement of boats, making it easier for nations with limited resources to apprehend the fishermen illegally depleting their oceans.
“We have to find a way to enforce [fishing laws],” Secretary of State John Kerry told The Washington Post. “We have to find a way to monitor it. And that’s very difficult in vast oceans with resources that are [limited]. We’re trying to create accountability where there is very little.”
Actor and environmental activist Leonardo DiCaprio will unveil the new technology Thursday at a conference for ocean preservation in Washington, D.C.
Illegal fishing practices deplete local populations and threaten oceanic habitats while also harming regulated fishing and local economies. As the world’s population continues to grow, protecting fisheries becomes an important way to ensure a sustainable food source for nations around the world.
A group of environmentalists began using the satellite system on a smaller scale two years ago, acting as watchdogs for the practice of illegal fishing and alerting the proper local authorities when something look awry, Scientific American reported. These included members of the tech-environmentalists group SkyTruth, the nonprofit Oceana, and at Google Earth Outreach.
Together, they developed a technology that pulls public data from satellites and land-based receivers through the Automatic Identification System, allowing them to chart how ships have moved. For some in the industry, the oversight is a welcome advancement, as they also hope to curtail illegal competition that depletes and destroys regulated fisheries and protected areas. Now, Global Fishing Watch tracks between 10,000 and 20,000 vessels each day.
“American fisheries are among the most sustainable – and regulated – in the world,” Tim Sloane, executive director of the Pacific Coast Federation of Fishermen’s Associations, told Scientific American. “[Illegal and unreported] fishing undercuts the steps American fishermen have taken to ensure that our fisheries are as healthy as they are.”
The technology isn’t a perfect solution. Some ships will shut their tracking services off, a move that’s only illegal in some countries where locator systems are required on large ships. Still, Global Fishing Watch has seen some initial success: After a tuna-fishing boat was seen illegally fishing in a protected area controlled by Kiribati, a Pacific island nation, the nation was able to levy a $1 million fine against the vessel’s operators, according to The Washington Post.
Those behind the technology hope that’s just the beginning, noting that Global Fishing Watch could be used to track ships for insurance purposes, or possibly to even find those who are trafficking drugs or people.
“We will be able to see a lot of information about who is fishing where,” Jacqueline Savitz, vice president for US oceans at Oceana, adding that the platform will help, told The Washington Post. She says the technology can “revolutionize the way the world views commercial fishing.”
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Read More »How Satellites and Big Data Can Help to Save the Oceans
May 17th, 2016
Courtesy of Yale’s e360, a look at how – with new marine protected areas and an emerging U.N. treaty – global ocean conservation efforts are on the verge of a major advance. But to enforce these ambitious initiatives, new satellite-based technologies and newly available online data must be harnessed:
Over the past century, rampant overfishing, severe pollution, and runaway coastal development have taken a huge toll on the world’s oceans. Now, however, two major advances in global ocean governance are quietly unfolding, offering hope that the early decades of the 21st century will mark a turning point in which humanity can begin to repair the global seas.
Yet a key question remains: Will the new availability of sophisticated, satellite-based technologies, coupled with the democratization of online data about the health of our environment, help ensure that these positive advancements live up to their potential to protect the oceans?
The first encouraging policy development is the explosive movement by countries around the world to set up massive marine protected areas of unprecedented size. The biggest of these newly proposed mega-marine protected areas, the Pitcairn Islands Marine Reserve, is three-and-a-half times larger than the United Kingdom, and more than 100,000 times larger than the historical median size for an ocean protected area. The 19 mega-marine protected areas created or announced in the last six years would comprise an area larger than all the protected ocean areas created previously. Several huge marine reserves currently being considered would add an additional 775,000 square miles of ocean protection.
The second key development is that the United Nations is now drawing up a treaty that would, for the first time, manage biodiversity across the high seas — the region outside the 200-mile exclusive economic zones of individual nations. The forthcoming United Nations high seas treaty would be setting new rules for a swath of the ocean 22 times larger than the United States. These new regulations are focused on preserving marine biodiversity, establishing international ocean reserves, evaluating processes for sharing marine genetic resources, and effectively carrying out environmental impact assessments.These bold new policies suggest that decision-makers are finally committed to taking the kind of aggressive actions needed to stay a step ahead of industrialization in the oceans — something we failed to do when industrialization occurred on land. This issue extends well beyond industrial-scale fishing. Recent innovation and technological development have now made it possible to take the industries of farming, mining, power generation, and even data center management underwater. The scope and significance of this mass acceleration of new uses of the ocean cannot be overstated. In 2014, for example, the world began eating more fish from farms than from the wild — a marine reprise of our historic shift on land from hunting wild food to farming. Mining claims have already been staked to roughly 400,000 square miles of deep-sea ecosystems.
The campaigns to vastly expand marine protected areas and significantly improve international governance of the oceans are extremely exciting. But both of these important policy movements have an Achilles heel: Laws only matter if you can ensure that people actually follow them. These new policies cover such vast areas that they render boat, plane, and other traditional forms of ocean observation as obsolete as sextants. In the absence of systems to watch their boundaries, large marine protected areas will be nothing more than huge paper parks. Likewise, our efforts to control the exploitation of high-seas biodiversity via the new U.N. treaty will only be effective if we aren’t blind to what is happening in this large and distant part of the ocean.
But just as technological innovation is fueling a rapid acceleration of development in the ocean, high-tech solutions may also hold the key to ensuring that a marine industrial revolution advances responsibly and intelligently. These advances, when put in the hands not just of governments but also of researchers, citizen-scientists and environmental groups, promise a new era in which we can actively observe and responsibly plan out what’s going on in the world’s seas.
A vital solution lies in the use of satellite-interfacing sensors and data processing tools that are beginning to allow us to watch how ships use the oceans as easily as we track Uber taxis cruising around a city. Like airplanes, more and more ships now carry sensors that publicly transmit their position so they don’t crash into each other. We can make use of these same streams of safety data to detect where industrial fishing is concentrated, to watch as seabed mining exploration begins, and to observe how cargo ships overlap with whale migration pathways.
Seaweed aquaculture emerging in the Taiwan Strait.Instead of the oceans being a black hole of data, our new challenge is figuring out ways to intelligently and efficiently sift through the billions of data points now pouring in. Fortunately, smart new algorithms can help pick out specific kinds of vessel behavior from this sea of big data. Ships leave unique behavioral fingerprints. For example, purse seine fishing boats make circles around fish schools when setting their nets, while long-line fishing boats travel linearly up and back along the gear they set.
In a recent report in the journal Science, colleagues at the non-profitGlobal Fishing Watch and I monitored progress as the nation of Kiribaticlosed a section of its ocean the size of California to fishing. After six months of observation, we happily saw that all vessels, save one, left to fish elsewhere. Our group also mapped out the activity of purse seine fishing boats on the high seas of the Pacific — generating the first publicly accessible view of where fishing activity occurs in the very region that the UN high seas convention may consider setting up international protected areas.
A key question ahead is whether governments will realize the value of this new data and act on calls from the scientific community to require that more vessels carry these observation sensors and use them properly. We estimate that approximately 70 percent of all large fishing vessels worldwide are already equipped with these publicly accessible tracking systems. Some captains, unfortunately, misuse the tool by turning it off after leaving port or failing to enter proper vessel identification information into the system. All such noncompliance issues are readily detectable by big data processing.If political will can be mustered to close these loopholes, these observation technologies could shed an immense amount of light on our now-dark oceans.
Orbiting in space alongside these ship-tracking satellites is another rapidly growing fleet of nanosatellites that constantly take high-resolution pictures of the earth. This technology promises to be an important additional piece in the ocean-observation puzzle. The goal of the groups tending to these flocks of tiny electronic eyes is to be able to take a high-resolution snapshot of the entire earth, every day. These new imaging satellites may soon allow marine ecologists, ocean conservation groups, and marine park managers to begin to search in near real-time for ships in protected areas, to monitor weekly (even daily) losses of coastal mangrove forests, and to document abuses to coral reefs, such as dredging. With foresight, the intelligence derived from the vessel tracking systems may eventually be interlinked with these imaging satellites to enable them to function like space-based red light cameras that snap pictures of law breaking at sea as it happens.
Not all next-generation ocean observation has to be based in outer space. An exciting array of new marine-monitoring technologies is increasingly available that also could be useful. Aerial drones are beginning to be used to patrol coastal waters. Fleets of drone ships may follow suit and could help monitor both the health of ocean resources, as well as the behavior of those that harvest them. Shore- and aircraft-based radar and acoustic recorders that listen for boat noise could also be deployed.
Essential to effectively monitoring and controlling the industrialization of the oceans is democratization of this new ocean-observation data. Good intelligence on what was happening at sea used to only be the purview of vessel captains.Now, anyone can keep tabs on the most remote parts of the ocean on their phones. Global Fishing Watch, for example, is releasing a product this year that will let anyone view and interact with data on fishing from across the global oceans for free. Planet Labs, a startup that manages the largest constellation of earth-observing nanosatellites, recently released a constantly updated, free library of imagery for all of California – including its estuaries, bays, kelp forests, and nearshore waters.
The challenge ahead, as we enter this new era of improved ocean stewardship and attempt to govern increasingly bigger regions of the ocean, is to ensure that our new policies are actually enforced. The stakes here are high. We have to make these emerging protected areas and treaties work, and we must do it soon, if we intend to help the oceans continue to dish out large helpings of food, energy, and wonder.
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Read More »Can Satellites Help Save The World’s Tigers From Extinction?
April 21st, 2016
Via GreenBiz, an interesting article on the role that satellite monitoring can play in tiger protection:
Tigers are one of the world’s most iconic animals, and yet also one of the most endangered. Despite their popularity in books, films and religion, fewer than 3,500 remain in the wild today, due largely to agriculture, logging and infrastructure expansion that’s destroyed 90 percent of their habitat.
The good news is that scientists agree that the tiger population can recover as long as its remaining landscapes are effectively monitored and protected. Researchers recently measured habitat loss in the world’s 76 tiger habitats over the past 14 years using data available on theGlobal Forest Watch tool.
They found that forest loss was much lower than anticipated across all tiger landscapes (roughly 19.76 million acres, or less than 8 percent of the total habitat). Thanks to preservation of habitat in countries such as Nepal and India, tiger populations in those countries already have increased 61 and 31 percent, respectively.
The study, conducted by researchers at the University of Minnesota, RESOLVE, Stanford University, the Smithsonian, University of Maryland and the World Resources Institute (WRI), sheds light on who’s responsible for tiger habitat loss, and points to important measures needed to preserve habitats and increase the big cats’ populations.
Hanging onto habitat
Tigers are solitary by nature and require vast expanses of habitat to survive. One key to ensuring adequate habitat range is protecting and restoring corridors — areas of land that connect large zones of habitat and allow otherwise separated tiger populations to disperse and interact.
Habitat loss or gain in these relatively small areas have major impacts on the viability of tiger populations, as demonstrated in Nepal.
The Khata corridor in Nepal’s Terai Arc Landscape — an area that encompasses three tiger conservation landscapes critical to achieving the global goal to double the wild tiger population by 2022 — gained tree cover over 2.7 percent of its area in the last 14 years.
The gain was in part due to a community-managed forestry program and anti-poaching patrol efforts to protect the habitat and its wildlife. Tigers now use this corridor to travel between Nepal’s Bardia National Park and India’s Katerniaghat Tiger Reserve, which likely has contributed to the impressive increase from 18 to 50 tigers between 2009 and 2013 in Bardia.
The population in the Terai Arc Landscape overall also increased 61 percent from 2009 to 2014. By contrast, the Basanta corridor, also in the Terai Arc Landscape in Nepal, lost some of its forest to encroachment and land clearing and is no longer used by tigers to move to and from the northern forests.
Although the loss was small — a mere 0.7 percent — because it occurred in a bottleneck area, it’s effectively severed connectivity between the northern and southern populations in this area and reduced habitat range.
Preventing future loss across all habitats is critical to recovering the tiger population. However, the amount of habitat lost since 2001 was much lower and more concentrated than expected, suggesting that park rangers, communities and policymakers should prioritize the most sensitive areas, such as key corridors, for conservation.
The role of agriculture
But it’s not all good news.
Findings also show that habitats where large-scale agriculture is driving deforestation are suffering the most. Ninety-eight percent of the total forest loss in tiger habitats was concentrated in just 10 landscapes. Those with the highest percentage of loss were in Indonesia and Malaysia, where conversion of forest to agriculture is a major contributing factor.
The Bukit Tigapuluh landscape in Sumatra, for instance, lost 67 percent of its forest cover since 2001. Oil palm and wood fiber concessions overlap with 42 percent of this landscape.
WRI research shows that the world will need to produce 70 percent (PDF) more food calories in 2050 than it does today to feed a growing population. Much of that demand will be met by commodities such as palm oil. Strong forest management practices will be critical to balancing agricultural expansion so that it happens on already degraded lands and doesn’t cause damage to intact tiger habitat.
Preventing big cats’ extinction
The findings are as cautionary as they are positive. If done right, the world has enough intact habitat to support doubling or evening tripling the tiger population in the coming decades.
Lower-than-expected loss in the Tiger Conservation Landscapes shows that progress is possible, but we can’t afford to lose any more. The habitat lost since 2001 could have supported 400 tigers — with just 3,500 remaining in the world, every tiger counts.
Experts also project that the world will invest $750 billion annually in infrastructure projects, including a superhighway that would bisect the Terai Arc Landscape. In short, protecting tiger habitats will require a concerted effort to balance the world’s growing demands with the right forest management practices.
These efforts will be enabled in large part by near real-time forest change data available on Global Forest Watch. Monthly and weekly tree cover change data can help park rangers and communities build off this research to continue monitoring the most at-risk habitats, and take action to stop forest loss before it affects tiger populations.
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Read More »To Take Earth’s Pulse, You Have To Fly High
October 25th, 2015
Courtesy of National Geographic, an interesting article on the use of satellite and airborne sensors to assess the environment:
The view out the window was bad enough. As his research plane flew over groves of California’s giant sequoias, some of the world’s tallest trees, Greg Asner could see the toll the state’s four-year drought had taken. “It looked wicked dry down there,” he said. But when he turned from the window to the video display in his flying lab, the view was even more alarming. In places, the forest was bright red. “It was showing shocking levels of stress,” he said.
The digital images were coming from a new 3-D scanning system that Asner, an ecologist with the Carnegie Institution for Science, had just installed in his turboprop aircraft. The scanner’s twin lasers pinged the trees, picking out individual branches from 7,000 feet up. Its twin imaging spectrometers, one built by NASA’s Jet Propulsion Laboratory (JPL), recorded hundreds of wavelengths of reflected sunlight, from the visible to the infrared, revealing detailed chemical signatures that identified each tree by species and even showed how much water it had absorbed—a key indicator of health. “It was like getting a blood test of the whole forest,” Asner said. The way he had chosen the display colors that day, trees starved of water were bright red.
Disturbing as the images were, they represented a powerful new way of looking at the planet. “The system produces maps that tell us more about an ecosystem in a single airborne overpass,” Asner wrote later, “than what might be achieved in a lifetime of work on the ground.” And his Carnegie Airborne Observatory is just the leading edge of a broader trend.
A half century after the first weather satellite sent back fuzzy pictures of clouds swirling over the North Atlantic, advanced sensors are doing for scientists what medical scanners have done for doctors—giving them ever improving tools to track Earth’s vital signs. In 2014 and early 2015 NASA launched five major Earth-observing missions (including two new instruments on the space station), bringing its total to 19. Space agencies from Brazil, China, Europe, and elsewhere have joined in. “There’s no question we’re in a golden age for remote sensing,” said Michael Freilich, NASA’s earth science director.Four years of drought have taken a harsh toll on California’s farms and forests. Last spring Greg Asner and his team flew over the Sierra Nevada, home to sequoias and other giant trees. With the new instruments on their airplane, the researchers completed in days a damage survey that would have taken a lifetime from the ground.
The news from all these eyes in the sky, it has to be said, is mostly not good. They bear witness to a world in the midst of rapid changes, from melting glaciers and shrinking rain forests to rising seas and more. But at a time when human impacts on Earth are unprecedented, the latest sensors offer an unprecedented possibility to monitor and understand the impacts—not a cure for what ails the planet, but at least a better diagnosis. That in itself is a hopeful thing.In California the water crisis has turned the state into something of a laboratory for remote-sensing projects. For the past three years a NASA team led by Tom Painter has been flying an instrument-packed aircraft over Yosemite National Park to measure the snowpack that feeds the Hetch Hetchy Reservoir, the primary source of water for San Francisco.Until now, reservoir managers have estimated the amount of snow on surrounding peaks the old-fashioned way, using a few gauges and taking surveys on foot. They fed these data into a statistical model that forecast spring runoff based on historical experience. But lately, so little snow had fallen in the Sierra Nevada that history could offer no analogues. So Chris Graham, a water operations analyst at Hetch Hetchy, accepted the NASA scientists’ offer to measure the snowpack from the sky.Painter’s Twin Otter aircraft, called the Airborne Snow Observatory, was equipped with a package of sensors similar to those in Greg Asner’s plane: a scanning lidar to measure the snow’s depth and an imaging spectrometer to analyze its properties. Lidar works like radar but with laser light, determining the plane’s distance to the snow from the time it takes the light to bounce back. By comparing snow-covered terrain with the same topography scanned on a snow-free summer day, Painter and his team could repeatedly measure exactly how much snow there was in the entire 460-square-mile watershed. Meanwhile the imaging spectrometer was revealing how big the snow grains were and how much dust was on the surface—both of which affect how quickly the snow will melt in the spring sun and produce runoff. “That’s data we’ve never had before,” Graham said.Painter also has been tracking shrinking snowpacks in the Rocky Mountains, which supply water to millions of people across the Southwest. Soon he plans to bring his technology to other mountainous regions around the world where snow-fed water supplies are at risk, such as the Himalayan watersheds of the Indus and Ganges Rivers. “By the end of the decade, nearly two billion people will be affected by changes in snowpacks,” he said. “It’s one of the biggest stories of climate change.”With less water flowing into California’s rivers and reservoirs, officials have cut back on the amount of water supplied to the state’s farmers, who typically produce about half the fruits, nuts, and vegetables grown in the U.S. In response, growers have been pumping more water from wells to irrigate fields, causing water tables to fall. State officials normally monitor underground water supplies by lowering sensors into wells. But a team of scientists led by Jay Famiglietti, a hydrologist at the University of California, Irvine, and at JPL, has been working with a pair of satellites called GRACE (for Gravity Recovery and Climate Experiment) to “weigh” California’s groundwater from space.
The satellites do this by detecting how changes in the pull of Earth’s gravity alter the height of the satellites and the distance between them. “Say we’re flying over the Central Valley,” Famiglietti said, holding a cell phone in each hand and moving them overhead like one satellite trailing the other. “There’s a certain amount of water down there, which is heavy, and it pulls the first satellite away from the other.”
The GRACE satellites can measure that to within 1/25,000 of an inch. And a year later, after farmers have pumped more water out of the ground, and the pull on the first satellite has been ever so slightly diminished, the GRACE satellites will be able to detect that change too.
Depletion of the world’s aquifers, which supply at least one-third of humanity’s water, has become a serious danger, Famiglietti said. GRACE data show that more than half the world’s largest aquifers are being drained faster than they can refill, especially in the Arabian Peninsula, India, Pakistan, and North Africa.
Since California’s drought began in 2011, the state has been losing about four trillion gallons a year (more than three and a half cubic miles) from the Sacramento and San Joaquin River Basins, Famiglietti said. That’s more than the annual consumption of the state’s cities and towns. About two-thirds of the lost water has come from aquifers in the Central Valley, where pumping has caused another problem: Parts of the valley are sinking.
Tom Farr, a geologist at JPL, has been mapping this subsidence with radar data from a Canadian satellite orbiting some 500 miles up. The technique he used, originally developed to study earthquakes, can detect land deformations as small as an inch or two. Farr’s maps have shown that in places, the Central Valley has been sinking by around a foot a year.
One of those places was a small dam near the city of Los Banos that diverts water to farms in the area. “We knew there was a problem with the dam, because water was starting to flow up over its sides,” said Cannon Michael, president of Bowles Farming Company. “It wasn’t until we got the satellite data that we saw how huge the problem was.” Two sunken bowls had formed across a total of 3,600 square miles of farmland, threatening dams, bridges, canals, pipelines, and floodways—millions of dollars’ worth of infrastructure. In late 2014 California governor Jerry Brown signed the state’s first law phasing in restrictions on groundwater removal.
As evidence has mounted about Earth’s maladies—from rising temperatures and ocean acidification to deforestation and extreme weather—NASA has given priority to missions aimed at coping with the impacts. One of its newest satellites, a $916 million observatory called SMAP (for Soil Moisture Active Passive), was launched in January. It was designed to measure soil moisture both by bouncing a radar beam off the surface and by recording radiation emitted by the soil itself. In July the active radar stopped transmitting, but the passive radiometer is still doing its job. Its maps will help scientists forecast droughts, floods, crop yields, and famines.
“If we’d had SMAP data in 2012, we easily could have forecast the big Midwest drought that took so many people by surprise,” said Narendra N. Das, a research scientist at JPL. Few people expected the region to lose about $30 billion worth of crops that summer from a “flash drought”—a sudden heat wave combined with unusually low humidity. “SMAP data could have shown early on that the region’s soil moisture was already depleted and that if rains didn’t come, then crops were going to fail,” Das said. Farmers might not have bet so heavily on a bumper crop.
Climate change also is increasing the incidence of extreme rains—and SMAP helps with that risk too. It can tell officials when the ground has become so saturated that a landslide or a downstream flood is imminent. But too little water is a more pervasive and lasting threat. Without moisture in the soil, a healthy environment breaks down, as it has in California, leading to heat waves, drought, and wildfires. “Soil moisture is like human sweat,” Das said. “When it evaporates, it has a cooling effect. But when the soil is devoid of moisture, Earth’s surface heats up, like us getting heatstroke.”
Despite all the challenges to Earth’s well-being, the planet so far has proved remarkably resilient. Of the 37 billion metric tons or so of carbon dioxide dumped into the atmosphere each year by human activities, oceans, forests, and grasslands continue to soak up about half. No one knows yet, however, at what point such sinks might become saturated. Until recently, researchers didn’t have a good way to measure the flow of carbon in and out of them.
That changed in July 2014, when NASA launched a spacecraft called the Orbiting Carbon Observatory-2. Designed to “watch the Earth breathe,” as managers put it, OCO-2 can measure with precision—down to one molecule per million—the amount of CO? being released or absorbed by any region of the world. The first global maps using OCO-2 data showed plumes of CO? coming from northern Australia, southern Africa, and eastern Brazil, where forests were being burned for agriculture. Future maps will seek to identify regions doing the opposite—removing CO? from the atmosphere.
Greg Asner and his team also have tackled the mystery of where all the carbon goes. Prior to flying over California’s woodlands, they spent years scanning 278,000 square miles of tropical forests in Peru to calculate the forests’ carbon content.
At the time, Peru was in discussions with international partners about ways to protect its rain forests. Asner was able to show that forest areas under the most pressure from logging, farming, or oil and gas development also were holding the most carbon—roughly seven billion tons. Preserving those areas would keep that carbon locked up, Asner said, and protect countless species. In late 2014 the government of Norway pledged up to $300 million to prevent deforestation in Peru.
Within the next few years NASA plans to launch five new missions to study the water cycle, hurricanes, and climate change, including a follow-up to GRACE. Smaller Earth-observing instruments, called CubeSats—some tiny enough to fit into the palm of a hand—will hitch rides into space on other missions. For scientists like Asner, the urgency is clear. “The world is in a state of rapid change,” he said. “Things are shifting in ways we don’t yet have the science for.”
Within the next decade or so the first imaging spectrometer, similar to the ones used by Asner and Painter, could be put into Earth orbit. It would be like “Star Trek technology” compared with what’s up there now, Painter said. “We’ve orbited Jupiter, Saturn, and Mars with imaging spectrometers, but we haven’t had a committed program yet for our own planet,” he said. The view from such a device would be amazing: We’d be able to see and name individual trees from space. And we’d be reminded of the larger forest: We humans and our technology are the only hope for curing what we’ve caused.
Earth’s vital signs are monitored by NASA’s 19 Earth-observing missions. Ten of the most critical, shown here, circle the globe up to 16 times a day, collecting data on climate, weather, and natural disasters.
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WHAT THIS IS It’s a map of atmospheric carbon dioxide over land last summer, made by NASA’s OCO-2 satellite. Red areas have a bit more CO?, green areas a bit less, than the global average of 400 parts per million.
WHAT THIS TELLS US Forests and oceans have slowed global warming by soaking up some of the CO? we emit. OCO-2 will shed light on where exactly it’s going—and on how fast the planet could warm in the future.
Forests
WHAT THIS IS The Carnegie Airborne Observatory made this image of rain forest in Panama with its scanning lidar, which probes the trees’ size and shape, and a spectrometer that charts their chemical composition.
WHAT THIS TELLS US The technique allows Asner’s team, flying at 7,000 feet, to identify individual trees from their chemical signatures—and even to say how healthy they are. The reddish trees here (the colors are arbitrary) are growing the fastest and absorbing the most CO?.
Water
WHAT THIS IS It’s an image of the Tambopata River in eastern Peru made by the scanning lidar aboard the Carnegie observatory.
WHAT THIS TELLS US The area in this image is actually covered with rain forest. Some lidar pulses penetrate the forest and reflect off the ground, revealing the subtle topography—red is a few feet higher than blue—and faint, abandoned river channels that have shaped the forest and helped create its rich biodiversity.
Land
WHAT THIS IS NASA’s Aqua satellite captured these visible-light images of California and Nevada on March 27, 2010 (left), the most recent year with normal snowfall, and on March 29, 2015 (right).
WHAT THIS TELLS US After four years of drought, the snowpack in the Sierra Nevada—a crucial water reservoir for California—is just 5 percent of the historical average. Snow has virtually vanished from Nevada. And west of the Sierra, in the Central Valley, much of the fertile farmland is fallow and brown.
No one gets a better look at how we’ve transformed Earth—and conquered night—than astronauts on the space station. The view here is to the north over Portugal and Spain. The green band is the aurora.
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