predictive capability at a seasonal level to infer conditions that favor the de- velopment of ARs, especially when you look at Madden-Julian Oscillation,” Jones said. “Because ARs are so very large and important for water supply, if you can predict the times that we may not have them, that is kind of a predis- position to a dry condition.” The Madden-Julian Oscillation is
the major fl uctuation in tropical weath- er on weekly to monthly timescales. It can be characterized as an eastward moving pulse of clouds and rain near the equator that typically recurs every 30 to 60 days.
Devil Canyon Powerplant, a State Water Project facility.
“Our natural resource reality is changing faster than our management institutions can adapt.”
– Lester Snow, California Water Foundation
The differences between climate change and historic climate variability are not that well understood, Jones said. “There are some things that show fi ngerprints of climate change, the easi- est being the earlier runoff of the Sierra Nevada snowpack, but there still needs to be an awful lot of work to disentangle climate change and variability at the time scale of forecasting an individual storm event or wet/dry season,” she said.
Hear more from Lester Snow
‘Changing Faster Than Our Management Institutions Can Adapt’ – A Conversation with Lester Snow When it comes to water in the West, Lester Snow has held a number of positions from which to observe the evolution of climate change under- standing. Snow’s career has taken him from Arizona, where he spent six years with the Arizona Department of Water Resources, to the San Diego County Water Authority, where he was general manager for seven years, to top-level assignments with the Bureau of Rec- lamation, CALFED, California DWR and the Natural Resources Agency. Snow, who now serves as execu- tive director of the California Water Foundation, worked on water issues while the understanding about climate change was still evolving. “Before climate change, it was talked about more generically as drought preparedness,” he said. It was while Snow was director at DWR that Gov. Arnold Schwarzeneg-
ger declared the debate about climate change over and “the time for action … now.” Seven years later, Snow said perceptions about climate change have noticeably changed.
“This debate over the man-induced climate change and all the deniers re- ally resulted in a delayed understanding or delayed response to the fact that our climate has changed rather dramati- cally and now I don’t see much of that,” he said. “People might avoid the discus- sion of how much of it is natural and how much is human induced, but you just don’t see anybody who’s waiting for it to go back to normal.”
Snow points to the Colorado River Basin, where awareness of changing conditions has risen, due in part to de- velopments such as the Colorado River Basin Water Supply and Demand Study, which noted that climate change, coupled with growing demands on the river, “may put water users and resources relying on the river at risk of prolonged water shortages in the future.” The “widespread understanding that our hydrology has fundamentally changed” has ushered a new water management paradigm, Snow said. “Four years ago, and certainly six years ago, I certainly think you heard people waiting for the snowpack to return, the lakes to fi ll back up, I think starting two years ago, you just didn’t hear much of that,” he said. “You started hearing important people like [Southern Nevada Water Authority General Manager] Pat Mulroy talking about adjusting to the new reality.” While the “hindrance has been too many people arguing over the reality of climate change,” Snow believes most water managers understand “snowpack is changing, storm patterns are chang- ing and boy, this year couldn’t be a more dramatic illustration of that.” Delineating climate change from historic climate variability isn’t a neces- sary part of the equation “if what we see is people simply preparing for the increasing risk and uncertainty in our water supply,” Snow said. “I think that’s what makes it easier ... where you have some politicians
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