LARAMIE - Citizens of Wyoming and the West wrongly believe global warming is something that will only seriously affect people on the coasts or other areas, state climatologist Steve Gray said.
Gray spoke at the Stroock Forum on Wyoming Lands and People at the University of Wyoming on Monday.
A recent poll, he said, found that 57 percent of Wyoming residents and 51 percent of Westerners think global warming is a bigger threat to others. Gray said Wyoming is instead "extremely vulnerable to climate change, no matter the cause." He added that it represents "a real and serious threat to Wyoming's water."
Seemingly small average temperature increases can generate serious consequences for Wyoming's water resources and economy, Gray said.
Even if precipitation levels in Wyoming do not decline as temperatures increase, he said, higher average temperatures of only 1 to 2 degrees Celsius could reduce the amount of water available in the latter part of the growing season. This scenario would create earlier and faster runoff of water stored as snow in the high mountains and cause more of the state's precipitation to fall as rain instead of snow.
Gray said Wyoming is the fifth-driest state in the nation. Most of its water comes from snowpack stored on 7 percent of the state's land - the high mountains. Thus, "we have all our eggs in one basket," he said.
Wyoming sits at the top of major watersheds such as the Colorado River Basin, which means, Gray said, a drought has greater impact on the state because shortages here cannot be buffered by excess precipitation elsewhere in the watershed.
Brad Udall, director of the Colorado University-National Oceanic and Atmospheric Agency's Western Water Assessment, told about 40 people attending the 11th annual forum that the "vast majority" of the world's scientists agree that human activity has played a significant role in global warming.
Udall said current carbon emissions into the atmosphere are turning out to be greater "than the worst-case scenario" used in one major study.
Both Udall and Gray said today's management systems are based on the assumption that climate changes will not vary significantly from historical patterns. Udall said it would be a mistake to continue to assume climate "stationarity," because "we know those records from the past are less and less true."
Udall showed photos of Lake Mead that indicated storage has dropped by a half in recent years. He said the mean annual temperature in the Lower Colorado River states has risen 2 degrees Fahrenheit since 1970, and he predicted that the heat will cause Arizonans to move to Colorado and Wyoming in the near future.
Udall and Gray also agreed that climate change is playing a role in the pine bark beetle epidemic. Gray presented maps showing large areas of tree kill in British Columbia and northern Colorado and said it was moving into Wyoming. Higher temperatures allow more beetles to survive the winter, then have a second life cycle in the summer, Udall said.
The tree kill and warmer temperatures create more fires, and the loss of the forests leads to faster runoff with more sediment, Gray said.
Larry MacDonnell of Boulder, Colo., a visiting professor in the UW College of Law this semester, noted that the legal system for regulating water use is based on "first in time, first in right," without giving major significance to the question of how the water is being used.
He said the North Platte River is fully appropriated already and is being impacted by decreasing runoff and increasing demand.
"The best thing we can do in water management is reduce new demands for water," he said.
One way to help address the water shortage problem is to store water underground - to avoid evaporation loss - in wet years, then reserve that water for drought years, he said.
Another event in the Stroock Forum will occur in Pinedale later this fall.