Although Arctic sea ice extent did not set a low record this year, it’s still clear that there is less sea ice than there used to be. Scientists are keeping a close eye not only on the dwindling ice, but also on the ripple effect its loss might have on the rest of the Arctic environment. A big question involves the exchange of heat between ocean and air—and the weather patterns that result. What does current research say about how floating ice—or the lack of it—might be changing the Arctic atmosphere? Continue reading
Have you been skiing in the Western U.S. and been surprised by brown snow? We recently talked to a research team that studies these coats of dirt. The dust storms that cause dusty snow appear to be getting bigger, thanks to climate warming drying out this region. Worse, dust on snow may increase flooding and slowly smother water supplies in the southwestern U.S. How bad is this situation and who will be affected by it? Can anything be done?
The what and where of dust
The more dust, the darker the surface and the faster snow will melt, because dark surfaces absorb more solar energy. “Sunlight is the major snow melter,” said Jeff Deems, a research scientist at NSIDC. “It’s not air temperature.” Fresh snow reflects anywhere between 90 to 95 percent of solar energy. “Very dusty snow, on the other hand, may reflect as little as 30 percent, meaning 70 percent is absorbed,” Deems said. If you more than double absorbency, you’re dramatically increasing the rate at which snow melts.
Dust storms boil out of the arid regions of the West. Jason Neff, a professor of Geology and Environmental Studies at the University of Colorado Boulder, said, “We know humans have increased dust by disturbing desert soils: grazing animals, driving vehicles, building roads and towns.” With the settlement of the West, post 1860s, dust has increased. “It wasn’t completely dust free before,” Deems said, “but by the mid to late 1800s the dust levels jumped up seven-fold.”
Is the extreme the new norm?
In recent years, increased temperature and prolonged drought have been drying the West. 2009, 2010, and now 2013 saw some very large dust storms. “There is indication from our colleagues out in the desert that the extreme scenarios could be a more frequent occurrence,” Deems said.
The extreme dust masses witnessed in 2009 and 2010 absorbed two to four times the solar radiation, and shifted peak snowmelt four to seven weeks earlier, compared to before the West was settled. Timing is everything. Scientists estimate that earlier soil exposure can decrease annual runoff by about 5 percent. Exposed land evaporates more water. Earlier snowmelt also triggers an earlier growing season, allowing for vegetation to take up and evaporate water. “Nothing can be done about the loss of water to evapotranspiration,” said Thomas Painter, a research scientist at the NASA Jet Propulsion Laboratory. “It’s permanent.”
The Colorado River brings water to more than 40 million people in cities like Denver, Las Vegas, Phoenix, and Los Angeles, punctuated by dams that store its water in reservoirs. Lakes Powell and Mead combined can store about four years worth of Colorado River flow, but for the Upper Colorado Basin, snowpack is the most important reservoir. “We can store way more water as snow in the mountains than we can in our reservoirs—vastly more,” Deems said. “So the longer the snow sticks around, the longer we have water. If flow comes early, then we’re stuck in late summer with only what could be stored in surface water reservoirs.”
Faster snowmelt also suggests a surge in river flow, and when rivers come up faster, water management gets complicated. “It’s just like if you turn on your sink, and if you only have a 101 gallons of water potential and your faucet blasts a hundred gallons out before you even get a cup underneath, then the person behind you in line may only fill their cup half full,” Painter said.
Climate models project that by 2050 the Colorado River will lose 5 to 20 percent of its total runoff. “It’s not good,” said Painter. “To put a dent in the flow like that—people are going to feel it.” The river irrigates 5.5 million acres of agriculture. But something can still be done. If the amount of dust blown onto Colorado River snowpacks can be reduced, a more stable snow pack lingers, giving way to a trickling river system rather than a roaring, untamable beast. Painter added, “By reducing dust loading, we may stem some climate change tide in terms of water loss.”
Deems, J. S., T. H. Painter, J. J. Barsugli, J. Belnap, and B. Udall. Combined impacts of current and future dust deposition and regional warming on Colorado River Basin snow dynamics and hydrology. 2013. Hydrology and Earth System Sciences Discussion 10, 6237-6275, doi:10.5194/hessd-10-6237-2013.
Painter, Thomas H., J. S. Deems, J. Belnap, A. F. Hamlet, C. C. Landry, and B. Udall. Response of Colorado River runoff to dust radiative forcing in snow. 2010. Proceedings of the National Academy of Sciences, doi:10.1073/pnas.0913139107.
People have asked how scientists know that today’s climate situation is unusual. Hasn’t the Earth undergone many cold and warm cycles before? Could this just be another? Buried in the world’s ice sheets is a long story of climate on Earth–and the contribution of atmospheric CO2 to warming or cooling. Scientists can access a unique and detailed look at the history of the Earth’s atmosphere through ice cores and start to understand the recent climate in context of past ones. Continue reading
If NSIDC scientists are busy all year long conducting their own research, how do they keep up with what their colleagues elsewhere are doing? They exchange flurries of emails and phone calls, of course, and collaborate on journal articles and projects. But once a year, many of them are in the same place at the same time for the same reason: to attend the fall meeting of the American Geophysical Union (AGU). Whether you’re interested in glaciers or geoids, sea ice or plate tectonics, Earth or Mars, AGU is right up your alley. Each year, more than 20,000 scientists, students, and educators converge in San Francisco for the weeklong meeting. Many of NSIDC’s staff participate in the meeting as well, presenting talks and posters detailing their latest research, data, and success stories.
Collaboration and the cryosphere
The meeting turns out to be a great place to run into normally-distant colleagues and discuss your research or hatch future collaborations. Scientists and project managers from around the globe also take advantage of AGU to coordinate with each other in person, saving the time and expense of setting up a separate meeting. Town Hall meetings provide government agencies, academic programs, and special projects with a forum to gather input from AGU attendees and convey information, which helps funding agencies set their priorities. NSIDC’s booth is also a big draw at the exhibit hall, where we feature some of our most recent and popular products. Talking with hundreds of meeting attendees helps us determine what kinds of data people are looking for, and how we can help them find what they need to conduct their research.
The variety of opportunities at AGU also fosters numerous informal meetings, whether we’re mingling between talks or at events like the Cryosphere Reception. This is often where new ideas can foment that would never come up in the more formal structure of science talks or project meetings. It is also a place to discuss better ways to improve understanding of science by students and the public and to communicate the latest science news at media briefings.
Among the cryosphere sessions, Greenland’s dramatic summer melt was a hot topic, as was sea ice, the effects of atmospheric carbon, and thawing permafrost. This year’s Nye lecture, one of the cryospheric highlights of the meeting, featured Elizabeth Morris of the Scott Polar Research Institute. Her talk, “Hot ice and wondrous strange snow: three-phase mixtures or something more?” delved into the process behind the science, how researchers study things in the field and then make that information useful in broader scientific contexts. The Nye lecture is just one of several plenary lectures that touch on a variety of disciplines, such as oceans, volcanism, and atmospheres.
Something for everyone
No matter what your discipline, AGU has something for everyone. Award-winning journalist Ira Flatow, host of National Public Radio’s “Talk of the Nation: Science Friday” program, spoke at the AGU presidential forum. He reminded all of us why science—and communicating that science clearly—is more important than ever. And the first annual AGU Open Mic Night: Tall Tales and Earth Sonnets, hosted by cryosphere expert Richard Alley, was a stratospheric success. If you didn’t get there early enough to get a chair, it was standing-room only.
Even when science is conducted in a vacuum, it’s never really conducted in a vacuum. The energy and synergy of ideas that occurs at AGU keeps us coming back. We’ll see you next year.
AGU Video on Demand, including the Nye Lecture and the Presidential Forum featuring Ira Flatow’s talk
Readers sometimes ask us, “What are the reasons behind Arctic sea ice decline?” In summer months, ice extent has declined by more than 30 percent since the start of satellite observations in 1979. But is climate change really the culprit, or could other factors be contributing? Continue reading