News on Climate Disruption, page 3

Water

Dust storms speed snowmelt in the West, Los Angeles Times, May 24, 2009; Spring runoff to be fast and furious, Aspen Times, May 21, 2009; and Dust storms escalate, prompting environmental fears, Washington Post, April 23, 2009.A new development in Colorado’s mountains, seen again this year, is spring dust storms that cover snowfields, absorb the sun's energy, and greatly hasten spring snowmelt. This is a double whammy for western water supplies, already affected by a hotter climate.  

Warming could spur water crisis, Arizona Republic, April 21, 2009. Researchers who last year made a controversial and disputed projection of a 50% chance that Lake Mead could go dry by 2021 release a new report asserting that continued patterns of decreased high elevation water production could lead to a 10% reduction in flows in the Colorado River, which would mean the reservoir would go functionally dry 60% of the time after 2050. Brad Udall, director of the Western Water Assessment, says that the new research avoids the problems of the earlier paper, and that "as you see Lake Mead continue to drop, you see a real-life manifestation of what's in this (research) paper."

Mulroy: Don't ignore warming, Las Vegas Review Journal, January 13, 2009.  Pat Mulroy, Southern Nevada Water Authority general manager, warns at a congressional hearing that three more years of drought along the Colorado River would cost Southern Nevada 40 percent of its water supply. "Two more years after that, we lose 90 percent of our water supply," she says.

Faster climate change feared, Washington Post, December 25, 2008. The U.S. Climate Change Science Program releases an Abrupt Climate Change Assessment suggesting that earlier projections depended upon by the Intergovernmental Panel on Climate Change may have underestimated how quickly climate change and its effects may happen. One primary example is prolonged droughts lasting more than a decade in the Southwest. Columbia University’s Richard Seager says that nearly all of the latest computer models agree on the Southwest droughts, and "If the models are correct, it will transition in the coming years and decades to a more arid climate, and that transition is already underway."

More rain, less snow in the Colorado River basin, Las Vegas Review-Journal, December 11, 2008. A study by University of Nevada-Las Vegas researchers finds that from 1951-2005, an increase in temperatures over the basin have caused more frequent rainfall and less frequent snowfall, leading to a decrease in snowpack and snowmelt and alterations in the hydrologic cycle.

Research says climate change already drying out Southwest, Associated Press, August 24, 2008. A University of Arizona researcher finds evidence that human-caused climate change has already caused a northward shift in the jet stream, making the region's late winter and early spring drier.

Future Snowmelt In West Twice As Early As Expected; Threatens Ecosystems And Water Reserves, Science Daily, July 16, 2008. P urdue University researchers discover that a critical surface temperature feedback is twice as strong as what had been projected by earlier studies. In addition to losing the reflectiveness of snow when it melts, a feedback loop is created when the soil heats up, and subsequently makes it more difficult for snow to accumulate, perpetuating the effect.

Governor declares drought in California and Water-starved California slows development , New York Times, June 5/7, 2008. Things are way worse in California where the driest spring in 88 years leads to a  statewide drought declaration and housing development approvals are delayed or denied due to lack of proven future water supplies.

Drying of the West, National Geographic, February, 2008. An in-depth look at the historical record of drought in the Colorado River basin, the additional impacts expected from climate change, and some of the solutions being explored.

Colorado River to drop to 500-year low as world warms, Bloomburg News, April 17, 2008.  A USGS study combining tree-ring records from 1490 – 1998 with climate change models projects a 1.5°F increase in the 21st century could reduce the average flow of the river by 8%, the low end of the 500-year historic record. A 3.6° F rise (more in line with the mid-range of climate projections) could reduce flows by 17%, pushing the average flow in the Colorado lower than any time during the 500- year period.

An IPCC Technical Paper on Climate Change and Water, released April 9, 2008, consolidates water-related findings spread through the IPCC’s 2007 Fourth Assessment Report.  The Executive Summary starts with:  “Observational records and climate projections provide abundant evidence that freshwater resources are vulnerable and have the potential to be strongly impacted by climate change, with wide-ranging consequences on human societies and ecosystems.” 

Lake Mead, key water source for southwestern US, could be dry by 2021, Science Daily, February 8, 2008, and Lake Mead Could Be Within a Few Years of Going Dry, Study Finds, New York Times, February 13, 2008. According to a new study by researchers at Scripps Institution of Oceanography , there is a 50% chance that Lake Mead and Lake Powell, the two major Colorado River impoundments that control the river’s flow and allocation between upper and lower basin states, could be dry by 2021. Based on assumptions that include current human demand, natural forces like evaporation, and moderate climate change models, the study identifies a net deficit of nearly 1 million acre-feet of water per year from the Colorado River system. “Today, we are at or beyond the sustainable limit of the Colorado system. The alternative to reasoned solutions to this coming water crisis is a major societal and economic disruption in the desert southwest; something that will affect each of us living in the region,” the report concludes.

The first study to demonstrate that observed changes in the hydrology of the West’s major river basins are likely caused by human-induced climate change was published in Science Express on January 31 (in abstract form only for free; readers can elect to purchase the full article online). The authors of the study include well known climate researchers from around the West. Based on observations of nine mountainous regions of the West for the period 1950-2000, the researchers found that up to 60% of the trends of warmer winter air temperatures, declining snowpacks, and earlier run-off can be attributed to human-caused climate change, rather than natural variability. In all but one range (the Sierra Nevada), water content of the snowpacks decreased, and in all ranges the January through March average minimum temperature increased, and peak river flows occurred earlier in the year.

Snowpack will melt earlier, scientist says, Grand Junction Daily Sentinel, January 24, 2008. A USGS research hydrologist finds that since 1980, the average date of snowmelt has advanced two weeks in Colorado, and that by 2100, it could come a full month earlier.