March 29, 2013
On the morning of July 16, 2010, a hunk of ice four times the size of Manhattan cracked away from the tongue of Greenland’s Petermann Glacier and drifted to sea as the largest iceberg since 1962. Just two years later, another massive section of ice calved from the same glacier. Icebergs like these don’t stay put in the Arctic–they get picked up by currents and ushered to warmer climates, melting along the way.
According to a new study published in the journal Geophysical Research Letters, Greenland’s melting glaciers and ice caps sent 50 gigatons of water gushing into the oceans from 2003 to 2008. This comprises about 10 percent of the water flowing from all ice caps and glaciers on Earth. The research comes on the heels of a study last year that showed the ice sheets of Greenland and Antarctica are disappearing three times faster than in the 1990s, and that Greenland’s is melting at an especially accelerated rate. In the new study, scientists were able to put an even finer point to the ice-melt situation by separating out the glaciers and ice caps from the ice sheet, which blankets 80 percent of the island. What they discovered is that Greenland’s glaciers are actually melting more quickly than the ice sheet.
Studies such as these demonstrate the impacts of a warming climate on Greenland’s glaciers. But, as they say, a picture is worth a thousand words. Visual evidence of this liquefaction is captured by NASA satellites, which are able to take snapshots of calving glaciers and document longer-term ice melt. NASA displays photos of the glaciers in its State of Flux photo gallery, along with a rotating collection of satellite images that illustrate other changes to the environment, including wildfires, deforestation and urban development.
The photos, with their “now-you-see-it, now-you-don’t” quality, illustrate how glaciers are fast becoming ephemeral. Here are a few stark examples:
The set of images above shows the edge of Greenland’s Helheim Glacier, located on the fringe of the Greenland Ice Sheet, as captured by a satellite in 2001, 2003 and 2005. The calving front is marked by the curved line through the valley, while bare ground appears brown or tan and vegetation is red.
According to NASA, when warmer temperatures initially cause a glacier to melt, it can spark a chain reaction that accelerates the thinning of the ice. As the edge of the glacier begins to liquefy, it crumbles, creates icebergs and eventually disintegrates. The loss of mass throws the glacier off balance, and further thinning and calving occurs, a process that stretches the glacier through its valley. Total ice volume decreases then shrinks the glacier as calving carries ice away. Helheim’s calving front stayed put from the 1970s until 2001, at which point the glacier began hasty cycles of thin, advance, and dramatic retreat, ultimately moving 4.7 miles toward land by 2005.
The massive calving event at Petermann Glacier in 2010 is pictured in these two images. The glacier is the white ribbon on the right side of each photo, and its tongue extends into the Nares Strait, which appears as a bluish-black stripe across the center of the right image and is heavily flecked with white chunks in the photo on the left. In the first image, the tongue of the glacier is intact; in the second, a huge chunk of ice has broken off and can be seen floating away through the fjord. This iceberg was 97 square miles in size–four times bigger than the island of Manhattan.
In the summer of 2012, a second massive iceberg crumbled away from the Petermann Glacier. In these images, the glacier is the white ribbon snaking up from the bottom right. If you follow the tongue up, you’ll see that it appears intact in the photos at left and center (though the center image has an ominous crack spanning its width), which were taken the day before the calving occurred. The photo on the right shows that it crumbled as the glacier calved.
Given that Greenland experienced an exceptionally warm summer in 2012 and temperatures were higher than average this winter, 2013 is primed for more melting and massive icebergs. Last year’s ice-melt season lasted two months longer than the average since 1979, and this year’s is already off to an inauspicious start. It kicked off on March 13 with the sixth-smallest sea-ice area on record for Greenland, according to the National Snow and Ice Data Center. What will the new summer calving season bring?
March 8, 2013
If you had to guess what part of the the U.S. has the very worst air pollution–where winds and topography conspire with fumes from gasoline-chugging vehicles to create an aerial cesspool–places like Los Angeles, Atlanta and as of late, Salt Lake City, would probably pop to mind. The reality may come as a bit of a surprise. According to the Environmental Protection agency, California’s bucolic San Joaquin Valley is “home of the worst air quality in the country.”
Not coincidentally, the San Joaquin Valley is also the most productive agricultural region in the world and the top dairy-producing region in the country. Heavy duty-diesel trucks constantly buzz through the valley, emitting 14 tons of the greenhouse gas ozone daily, and animal feed spews a whopping 25 tons of ozone per day as it ferments, according to a 2010 study. In addition, hot summertime temperatures encourage ground-level ozone to form, according to the San Joaquin Valley Air Pollution Control District. Pollution also streams down from the Bay Area, and the Sierra Nevada Mountains to the east help to trap all of these pollutants near the valley floor. Particulate matter that creates the thick greyish-brown smog hanging over the valley is of paramount concern–it’s been linked to heart disease, childhood asthma and other respiratory conditions.
So when NASA devised a new, five-year air quality study to help fine-tune efforts to accurately measure pollution and greenhouse gases from space, it targeted the San Joaquin Valley. “When you’re trying to understand a problem, you go where the problem is most obvious,” the study’s principal investigator, Jim Crawford, said in an interview. To Crawford, the dirty air over the valley may be important to evaluating how human activities contribute to climate change. “Climate change and air quality are really traced back to the same root in the sense that air quality is the short term effect of human impact and climate change the long term effect,” Crawford said.
In January and February, NASA sent two research planes into the skies above San Joaquin Valley to collect data on air pollution. One plane flew at high altitude over the valley during the daytime, armed with remote sensors, while the second plane cruised up and down the valley, periodically spiraling down toward the ground to compare the pollution at higher and lower altitudes. Weather balloons were used for ground-level measurements as well.
The data NASA collected in the experiment was similar to what satellites can see from space: the presence of ozone, fine particulates, nitrogen dioxide and formaldehyde (precursors to pollution and ozone) and carbon monoxide (which has a median lifetime of a month and can be used to watch the transport of pollution). But satellites are limited in their air-quality-sensing abilities. “The real problem with satellites is that they’re currently not quantitative enough,” Crawford told Surprising Science. “They can show in a coarse sense where things are coming from, but they can’t tell you how much there is.”
Nor can satellites distinguish between pollution at the ground level and what exists higher in the atmosphere. Also, they circle just once a day, and if it isn’t in the early morning, when commuters are busily burning fossil fuels, or in the late afternoon, when emissions have festered and air quality is at its worst, scientists don’t have a clear picture of just how bad pollution can get. Monitoring stations on the ground are likewise limited. They provide scientists with a narrow picture that doesn’t include the air farther above the monitoring station or an understanding of how the air mixes and moves. The research from the NASA study, specifically that collected by the spiraling airplane, fills in these gaps.
Data from the flights will also be used in conjunction with future satellites. “What we’re trying to move toward is a geostationary satellite that will stare at America throughout the day,” Crawford told Surprising Science. Geostationary satellites–which will be able to measure overall levels of pollution–can hover over one position, but like current satellites, researchers need ancillary data from aircraft detailing how pollution travels above the Earth’s surface, like that retrieved from the San Joaquin Valley, to help validate and interpret what satellites see. “The satellite is never going to operate in isolation and the ground station isn’t going to do enough,” Crawford said.
But first, the research will be plugged into air-quality computer models, which will help locate the sources of emissions. Knowing how sources work together to contribute to poor air quality, where pollution is and exactly what levels it’s hitting is a priority for the EPA, which sets air-quality regulations, and the state agencies that enforce them, according to Crawford. The data will inform their strategies on reducing emissions and cleaning the air with minimal impact to the economy and other quality-of-life issues. “Air quality forecasts are great,” Crawford says. “But at some point people will ask, ‘Why aren’t we doing something about it?’ The answer is that we are.” The researchers have conducted similar flights over the Washington, D.C. area and are planning flyovers of Houston and possibly Denver in the years to come.
One thing’s for sure: Data to inform action is sorely needed. In 2011, Sequoia and Kings Canyon National Park, on the eastern edge of the valley, violated the EPA’s national ambient air quality standard a total of 87 days of the year and Fresno exceeded the standard 52 days. Pinpointing exactly where pollution originates and who’s responsible–a goal of the study–will go a long way to clearing the air, so to speak.
February 15, 2013
Climate change, believed to have contributed to the decline of the Ottoman Empire (PDF) when drought forced villagers into a nomadic life in the late 16th century, is once again having an adverse affect on the Middle East. Precipitation has dropped off and temperatures have climbed for the past 40 years, with conditions growing especially severe in the last decade. A 2012 Yale study (PDF) showed that a drought from 2007 to 2010 so seriously stunted agriculture in the Tigris and Euphrates river basins that hundreds of thousands of people fled Iran, eastern Syria and northern Iraq.
A new study published today in the journal Water Resources Research puts an even finer point to the climate change fall-out in the Middle East: The Tigris and Euphrates river basins lost 117 million acre-feet of their stored freshwater from 2003 to 2010, an amount almost equivalent to the entire volume of water in the Dead Sea. The research, conducted by scientists at UC Irvine, NASA’s Goddard Space Flight Center and the National Center for Atmospheric Research, is one of the first large-scale hydrological analyses of the region, encompassing parts of Turkey, Syria, Iraq and Iran.
Drought typically sends water-users underground in search of aquifers, and in the midst of the 2007 water crisis, the Iraqi government, for one, did just that, drilling 1,000 wells. Such pumping has been the primary cause of recent groundwater depletion, according to the new study. Sixty percent of the lost water was removed from underground reservoirs, while dried-up soil, dwindling snowpack and losses in surface water from reservoirs and lakes exacerbated the situation. “The [groundwater storage loss] rate was especially striking after the 2007 drought,” hydrologist Jay Famiglietti, principle investigator of the study and a professor at UC Irvine, noted in a statement. Overall, the area has experienced “an alarming rate of decrease in total water storage,” he added.
Since gathering information on the ground in a region marked by such political instability isn’t very practical–or in some cases, even possible at all–the scientists instead utilized data from NASA’s Gravity Recovery and Climate Experiment (GRACE) satellites. These satellites measure a region’s gravitational pull; over time, small changes observed in the strength of this pull are influenced by factors such as rising or falling water reserves. From this, the scientists uncovered variations in water storage over much of the last decade.
The video below is a visualization of groundwater fluctuations in the Tigris and Euphrates basins using GRACE satellite imagery; blues represent wet conditions and reds are indicative of dry conditions. The drought that began in 2007 is clearly reflected.
“The Middle East just does not have that much water to begin with, and it’s a part of the world that will be experiencing less rainfall with climate change,” said Famiglietti. “Those dry areas are getting dryer.” In fact, the region is experiencing the second-fastest rate of groundwater storage loss on the planet, surpassed only by India.
Yet, demand for freshwater continues to rise worldwide, including in the U.S., where aquifer depletion is also a growing problem. Groundwater supplies in the Southwest and western Great Plains have been stressed for many years, according to the United States Geological Survey (USGS). The area surrounding Tucson and Phoenix in south-central Arizona has seen the highest drop in groundwater levels–300 to 500 feet–but other regions have also suffered. Long Island and other parts of the Atlantic coast, west-central Florida and the Gulf Coast region–notably Baton Rouge–are out of balance. And perhaps most surprisingly, the Pacific Northwest is experiencing groundwater depletion as a result of irrigation, industrial water use and public consumption.
According to study co-author Matt Rodell of NASA, such depletion is unsustainable. “Groundwater is like your savings account,” Rodell said. “It’s okay to draw it down when you need it, but if it’s not replenished, eventually it will be gone.”
What’s to be done? More research, according to the authors of the new Middle East study. “The opportunity to construct the most accurate and holistic picture of freshwater availability, for a particular region or across the globe, is now on us,” they wrote. “Such science-informed studies are essential for more effective, sustainable, and in transboundary regions, collaborative water management.” Building on that last point, they called for international water-use treaties and more consistent international water laws.
They will also spread word of their findings by traveling to the Middle East. Famiglietti and three of his UC Irvine colleagues, including the study’s lead author, Katalyn Voss, are heading to Israel, Palestine and Jordan tomorrow to share their data with water authorities, scientists, water managers and NGOs; verify the GRACE measurements with locally obtained data; and begin collaborating with local groups on hydrology and groundwater-availability research.
They hope to educate themselves on the region’s best practices for water efficiency, with the goal of introducing those techniques to other water-strapped areas, including California. “Ideally, this trip will set the foundation for future research collaborations in the region, with universities and government agencies, as well as provide an opportunity for cross-regional learning between California and the Middle East,” Voss told Surprising Science.
February 1, 2013
It’s become a destructive cycle in the western U.S.: Warmer temperatures and drought conditions prolong the life cycle of mountain pine beetles, allowing them to prey on the pine, spruce and fir trees that blanket the mountains. The trees turn reddish-brown before dying off–a phenomenon the National Park Service deemed “an epidemic stretching from Canada to Mexico.” There’s widespread concern that such tree mortality creates an excellent fuel source for wildfires.
Until recently, scientists were left to survey the damage from the ground, with little ability to understand the causes and processes. But now new technology is enabling them to use satellite imagery to identify the sources of small, ecosystem-altering events–some of which, for example beetle outbreaks, are related to climate change drivers. A computer program called LandTrendr, developed by Boston University Earth and Environment professor Robert Kennedy, allows scientists to combine data they collect on the ground with satellite imagery from the U.S. Geological Survey (USGS) and NASA to get a better understanding of environmental disturbances.
Since 1972, NASA and the USGS have deployed satellites that snap specialized digital photographs of Earth’s landscapes. They’re able to capture details that exist in wavelengths invisible to the human eye, including those slightly longer than visible light called the near infrared. Healthy plants reflect energy in the near infrared, and by scanning the imagery, scientists can detect disruptions in Earth’s landscapes.
In the past, these images were prohibitively expensive, limiting scientists’ access. “We’d look at an image from 2000 and one from 2005 and ask, ‘What’s changed?’” Kennedy explained. “If you’re only looking at two images, it’s very difficult to track slowly evolving changes. You can tell something’s changed, but you don’t know how long it’s taken.”
When the USGS began providing these images for free in 2008, it was a turning point for Earth scientists. They now had access to thousands of shots of any given geographic region–images that Kennedy’s LandTrendr tool utilizes. “By looking at all the images, you can watch [changes] unfold. You have more confidence that you’re actually seeing trends,” he said. This is particularly useful for understanding climate change and land use change, which are “all about process,” according to Kennedy.
Kennedy is currently using LandTrendr technology to look at the net carbon exchange of forests; among other things, his work analyzes the amount of carbon lost in forests due to fire, clear cuts, partial cuts and urbanization. Studies of climate change in the Arctic and in transition zones between ecosystems are also utilizing LandTrendr. But in the Pacific Northwest, Garrett Meigs, a forestry PhD candidate at Oregon State University, is using LandTrendr to study the intersection of wildfire and insects.
Specifically, Meigs is examining the large wildfires that have ravaged Washington and Oregon since 1985, and how outbreaks of the mountain pine beetle and western spruce budworm affect subsequent fire activity. “When there’s drought, stress, a higher susceptibility to infestation, we can see the dieback of forest,” he said.
The LandTrendr algorithm incorporates satellite images of the regions affected by fire and bugs with Meigs’ own fieldwork and historical aerial data from the U.S. Forest Service, which has long used airplanes to survey insect infestations. “There were things we couldn’t detect or see before, but now we’re able to,” Meigs said.
Below is a video showing a LandTrendr visualization of the Pacific Northwest. Kennedy explains how it works: Stable evergreen forests are represented by the blue areas; when a mountain pine beetle infestation erupts, in this case in the Three Sisters area of Oregon, the imagery glows red. And when a slow-moving western spruce budworm moves into an area–there, the southern foothills of Mount Hood–it morphs yellow.
Could LandTrendr help predict climate change? Possibly. “We can’t see the future, we can only document with the satellites what has happened. But the whole game with science is to develop understandings that allow for prediction,” Kennedy says. “My hope is that by creating these maps and capturing these processes in ways we haven’t been able to see them before, we can test [climate change] hypotheses” by documenting where, when and if predicted effects occur, he said.
While Meigs’ study of insects and wildfire is largely retrospective, it has the potential to aid in future forecasting efforts. “We have a baseline to measure future change,” he says. “By seeing the conditions leading up to big insect outbreaks or wildfires, we may be able to recognize them as they emerge in the future.”
January 16, 2013
NASA first dipped its toe into climate-change research in the 1980s by using satellite and aircraft imaging. Its efforts grew more serious with the launch of a large network of satellites in 1991. And by 2004, the agency was spending $1.3 billion annually on climate science. It now has more than a dozen spacecraft studying everything from the oceans to the atmosphere to the cryosphere (the Earth’s frozen bits). On Friday, it will add the stratosphere to that list when it launches an unmanned Global Hawk aircraft from California’s Edwards Airforce Base.
The project, called Airborne Tropical TRopopause EXperiment (ATTREX), will study humidity in the tropical tropopause layer, the area of the atmosphere eight to 11 miles above the Earth’s surface that controls the composition of the stratosphere. According to ATTREX scientists, small changes in stratospheric humidity can significantly affect climate. “Cloud formation in the tropical tropopause layer sets the humidity of air entering the stratosphere,” principal investigator Eric Jensen says, adding that the pathways through the tropical tropopause influence the chemical composition of the stratosphere.
Although the group won’t focus on the impact of standard greenhouse gases such as carbon dioxide and methane, water vapor is a powerful greenhouse gas, and understanding its variability within the stratosphere is the group’s priority. Filling in this gap, they believe, will allow scientists to forecast how changes in the stratosphere affect global climate change, which will in turn improve the accuracy of mathematical models used in climate change predictions.
The tropopause and stratosphere have proven elusive to climatologists until now. “We’ve been wanting to sample this part of the atmosphere for a long time,” Jensen says. The problem has been access — a specialized high altitude aircraft is necessary to conduct this type of research.
Enter the Global Hawk, which can travel up to 65,000 feet into the atmosphere for up to 31 hours at a time and is fitted with instruments that can measure surrounding temperatures, clouds, trace gases, water vapor, radiation fields and meteorological conditions. All of this will let the ATTREX team sample a range of conditions over a large geographic span. Test flights conducted in 2011 showed that the Global Hawk and its instruments can withstand the frigid (as low as minus-115 degree Fahrenheit) temperatures above the tropics.
They’ll send the craft above the Pacific Ocean near the equator and off the coast of Central America six times over the course of the next two months, monitoring it from the ground while it’s in flight. “We get high-speed real-time data back from the aircraft via satellite communications,” Jensen says. “The instrument investigators monitor and adjust their instruments, and we use the real-time data to adjust the flight plan throughout the flight.”
ATTREX is one of the first projects launched by NASA’s new Earth Ventures program, which provides five years’ funding to low- to moderate-cost missions. This is far more time than previous airborne-science studies, and the ATTREX crew will use the added time to re-launch the Global Hawk in winter and summer 2014, allowing them to look at seasonal variation.
The longer timeframe is also conducive to international collaborations. In 2014, the ATTREX team will venture to Guam and northeastern Australia. In Guam, they’ll connect with British researchers, who will be using a low-altitude aircraft to study climate change, and a National Science Foundation crew doing similar research with a G5. “We’ll have measurements from the surface all the way to the stratosphere,” Jensen says. “And we’ll be able to connect emissions at ground level up to measurements of the composition in the stratosphere.”