NEWS

Climate change to threaten Nevada water supplies

07/25/2008

By Jeff DeLong

Climate change could come with profound risk to Nevada’s water supplies and at great cost to the state’s economy, a new study asserts.

The report released this week by the National Conference of State Legislatures and Center for Integrative Environmental Research concluded that rising temperatures associated with a warming climate could create "profound drought conditions" in Nevada, which was examined along with 11 other states around the country.

"Some of these impacts are already noticeable and it’s certainly not going to get better as climate change progresses," said Daria Karetnikov, a researcher at the University of Maryland who compiled the report.

By 2100, climate change brought about by greenhouse gas emissions could cause the average temperature in Nevada to increase by up to 4 degrees Fahrenheit in spring and fall and by up to 6 degrees in the summer and winter, the report said.

The result will be changes in precipitation and evaporation patterns and decreased water availability statewide, the report contends.

Costs could be high. Citing a 2004 study by the Southern Nevada Water Authority, the report said scaling back development to manage diminishing water resources could translate into a loss of $18.6 billion in tax revenue and $4.7 billion per year in lost wages. Water-based recreation bringing in more than $1 billion annually could also be damaged.

Some of the most dire impacts cited by the report would occur in the Las Vegas area. The report cites studies by the Scripps Institution for Oceanography indicating there is a 10 percent chance that Lake Mead, the water source for 2 million people, could dry up by 2021 and a 50 percent chance it could go dry by 2050.

In Northern Nevada, the Sierra snowpack that Reno, Sparks, Carson City and other communities depend upon for water also could be endangered, Karetnikov said. Research suggests that as the climate warms, more precipitation will fall as rain instead of snow and the mountain snowpack will melt earlier in the year.

It’s an issue that definitely deserves attention, agreed Kelly Redmond of the Western Regional Climate Center in Reno.

"It’s not the amount, it’s the form it falls in," Redmond said. "It’ll be more rain and less snow."

That could prove a challenge for water managers who could be forced to keep reservoirs at lower levels to prevent flooding caused by winter rains, Redmond said.

Rapid melting of the snowpack rather than the slow and measured melting that occurred historically over the spring could make it difficult to capture runoff for storage in the summer when water is needed most.

And rising summer temperatures could heighten water demand at the same time, Redmond said.

"If the demand goes up and the supply stays roughly constant, in the end you have a net loss," Redmond said.

Lori Williams, general manager of the Truckee Meadows Water Authority, agreed that climate change is an important consideration when planning for long-time management of water supplies.

"This is of key concern to us," Williams said.

One problem Williams sees is a lack of modeling showing what can be expected on a regional, rather than global, basis. That makes it hard to determine what a changing climate could mean locally, she said.

"The bottom line is you’re going to expect more severe weather—more severe droughts, more severe floods," Williams said. "You can really expect more variability in weather patterns."

The Reno area is fortunate in that it is served by a system of high elevation reservoirs that will help diminish impacts of a warming climate, Williams said. It also has both surface and ground water supplies and significant drought storage in its reservoirs. Such water supply diversity is expected to become increasingly important in the years ahead, she said.

The new study is important because it drives home the message that climate change has direct impacts at home, said Dan Cronin, spokesman for the Environmental Defense Fund, which helped fund the report.

Many people still associate the issue of global warming with images of melting icebergs and polar bears, Cronin said.

"The most important take away is that climate change is something that is happening here," Cronin said. "If we don’t take action now, climate change is going to be felt by people in Nevada, people in Ohio and people across the country. We need to take it seriously."