14 December 2009
The star of Monday’s early morning hydrology poster sessions is GRACE. I can’t exactly call her to talk, though. GRACE, a NASA satellite, has been tracking the total amount of fresh water on the surface of the Earth for seven years counting. I’ve seen GRACE’s name on at least a half-dozen posters in the hydrology aisles.
Climate-Related Trends, Human Induced Trends, and False Trends in Seven Years of Terrestrial Water Storage Observations from GRACE, by Matt Rodell (NASA GSFC), Jay Famiglietti (UC Irvine) and Don Chambers (U. South Florida)
Poster #810, seen above, is a color-coded map of GRACE’s water data from the past seven years. Much of the world is grass-green, indicating little or no change. But a huge, flaming red splotch engulfs Greenland, and smaller orange spots flare along the southern coast of Alaska and in the southeastern US. The one in the southeast is the 2007-2008 drought; that’s the reason I pared my showers down to 30 seconds apiece when I lived in North Carolina.
The hot spots in Alaska and Greenland are melting glaciers. Since GRACE launched, warming temperatures have eaten a chunk the size of Everest out of the Greenland ice sheet.
“This trend is real, associated with climate change, and likely to continue,” the pop-out box says.
But I also see another theme in the posters, and it’s not alarming. It’s hopeful! Scientists from a wide variety of disciplines are cooking up novel ways to address global water shortages. The basic problem: more people need more food and more water to grow food. Thirsty crops soak up anywhere from half to 90 percent of the groundwater in farming regions around the world, and in many places farmers are pumping the wells dry.
How to balance the need for water conservation with the need to grow food? A group from Columbia University is proposing a cap-and-trade market for water-strapped agricultural areas in northern India. Farmers are guaranteed an amount of water corresponding to their usual use. They have to pay for more, but if they have extra they can sell it. It’s like the one for carbon that’s been floating around at climate change conferences.
California has been wrangling with water issues, and this sort of market approach to water resources has come up. The big “if” seems to be whether it’ll be enough incentive to get farmers to invest in more water-efficient technology. The Indian government subsidizes drip irrigation technology, but farmers have been slow on the uptake, said Ram Fishman, one of the Columbia researchers. In Monterey County, the salad bowl of California, farmers have voluntarily adopted conservation measures, but their wells, ruined by saltwater, spur them on. Cultural factors like education and social marketing might have to come into play to accelerate changes in the way people use water.
–Sandra M. Chung, UCSC Science Communication Graduate Student