Showing posts with label drought. Show all posts
Showing posts with label drought. Show all posts

Thursday, March 15, 2007

More Drought News



John Fleck at Inkstain reports today on some drought news from around the world, including camels mad with thirst in Austalia. Well, no mad cows to report here in Colorado, but on the University of Colorado campus, abnormal warmth has ushered in flip flop season. So I thought it would be interesting to describe the details of a developing drought in the West that has some people worried.

Sixty percent of the region is now abnormally dry — or worse — according to the U.S. Drought Monitor. About 27 percent of the West is either in severe or exceptional drought, including nearly the entire state of Wyoming. The National Resources Conservation Service predicts that streamflows in a large swath of the West will be significantly below normal in spring and summer. Some flows are expected to be less than 50 percent of normal.

In the Upper Colorado River Basin, drought conditions from 2000 through 2004 had reduced the water level in Lake Powell so much that storage in the reservoir reached a low of 33 percent of capacity. Wetter conditions in 2005 improved the situation a bit, but drier conditions returned to the upper basin in 2006 — and things aren't looking any better now, according to the U.S. Bureau of Reclamation. Precipitation in the basin was below average from November through January, and inflows into the lake from April through July are forecast to be just 71 percent of average.

That situation could turn around If spring precipitation turns out to be much above average. But that seems unlikely, now that the fall's moderate El Niño has rapidly dissapated, and conditions are becoming favorable for a La Niña to develop. (See the El Niño/Southern Oscillation Diagnostic Discussion issued by the National Weather Service's Climate Prediciton Center.) Some forecast models are predicting a rapid onset of La Niña conditions between March and May.

"With the potential for a rapid transition to La Niña conditions in the next few months, the odds of a wet spring are certainly not improving," says Klaus Wolter, of NOAA's Climate Diagnostics Center. A rapid demise of El Niño like we've seen does not favor wet springs in the West. "If we were to see the emergence of La Niña conditions later this spring, the threat of renewed drought conditions would increase even more."

Now, a paper by Mark Serreze, a senior researcher at the University of Colorado's National Snow and Ice Data Center, suggests new reasons why the future may bring even more frequent and prolonged droughts. According to Serreze's paper in the March 16 issue of Science (abstract here , and press release here), declines in Arctic sea ice, which may have already reached a "tipping point," could trigger changes in weather patterns that would favor reduced rainfall in the West. "Just how things will pan out is unclear, but the bottom line is that Arctic sea ice matters globally," Serreze says.

Snow, ice and cold temperatures have given way quickly to abnormal warmth and mostly dry conditions here in the Front Range of Colorado. My precious silver maple in the back yard is already flowering. A bit early, I think.

-- Tom Yulsman

Monday, February 5, 2007

Global Warming Goes Local

With the release Friday of the IPCC report on global warming (caution: 2mb file), climate change became the top online story on Google News. At one point, Google News listed 1,985 new stories. Now that the dust has settled, how do we journalists proceed?

It's clear that the 'yes or no' debate over the big question of whether humans are causing global warming is now over, and that debate about policy options is really getting started. This will certainly be a rich area for exploration by journalists in the coming years. But scientific debate is by no means over. It is shifting to the details of what global warming means. The predicted 3.5 to 8 degree Fahrenheit rise in global average temperature with a doubling of carbon dioxide concentration in the atmosphere doesn't sound all that bad. But a global average temperature doesn't mean much. What we really want to know are the answers to questions like these: How much is sea level going to rise in, say, Florida or Bangladesh?; Are diseases like dengue fever going to spread into new areas, including the southern tier of the United States?; Will drought become more common and intense in the West, putting additional strain on already stressed water resources?

Today's Boulder Daily Camera features a story that may give us a preview of what's to come. The article is about a dispute pitting the City of Boulder and other water users against farmers in the South Platte River basin. Colorado law requires farmers to replace the water they take from wells. And in 2006, the state's water court shut down the wells of farmers in the South Platte basin because they were not abiding by the law. Today, the farmers will face off in water court in Greeley against the City of Boulder. According to the Camera, they are hoping that the court will allow them to draw some of the water they had been removing from wells.

At the heart of the battle, pitting a city against one group of farmers, is the West's complex system of water rights. But it is, of course, taking place in a bigger context that will be getting increasing attention in future years: With population growth putting increasing demand on water resources across the West, conflict between municipal and agricultural users is likely to increase. And this will only be magnified if global warming leads to significant changes in runoff patterns and more frequent periods of extended droughts. Make no mistake about it: The science shows that such changes may be on the way. For just one example, see this review article from the journal Nature, published in 2005: http://stripe.colorado.edu/~yulsman/nature04141.pdf.

How are we going to manage this situation? Should we be planning to build more storage capacity? How much of a commitment should we be making to preserving agriculture in a region where growing crops is much more difficult than in better-watered areas to the east? What does the science say about global warming's impact on our region? These and related questions are likely to form the basis of stories for years to come. Are you ready to cover them?