Climate changes evident in West, experts say

The Olympian online, via McClatchy: With snowfall diminishing at "statistically significant" rates, spring runoff coming earlier and a dead zone the size of Rhode Island in the ocean off the Oregon coast, senators were told Wednesday that global climate change is already being felt in the West.

Dam operators, water district managers, farmers, conservationists and scientists all predicted mounting problems as scarce water supplies dwindle further in an area stretching from the Northwest to the desert Southwest.

"The warming in the West can now confidently be attributed to rising greenhouse gases and are not explained by any combination of natural factors," said Philip Mote, head of the Climate Impacts Group at the University of Washington. Mote said some models show temperatures in the West could rise by 6 degrees Fahrenheit in the coming years. Signs of climate change, such as lilacs blooming earlier in the spring, are just a "harbinger of changes to come," he said.

Among other things, the Senate Energy and Natural Resources water and power subcommittee learned:

--Spring snow pack already has declined at nearly 75 percent of all weather recording stations in Washington, Oregon and California, and the spring runoff is coming two weeks earlier than in the past.

--Southern California is experiencing its driest year on record, and Lake Mead, which supplies water to large parts of the fast-growing Southwest, could be empty in 10 years.

--By some estimates, populations of Pacific salmon in the Northwest could drop between 20 percent and 40 percent by 2050, with even greater losses in California and Idaho. Western trout populations eventually could fall by more than 60 percent.

--A dead zone of "very low dissolved oxygen" has appeared every year in the Pacific Ocean off the Oregon coast since 2001, and unlike other ocean dead zones, pollution or other human activity isn't believed to be the cause. Instead, some scientists say there may be a "fundamental change" occurring in the ocean off the West Coast, changes that may involve wind patterns "modified" by climate change.

--Tens of thousands of irrigated acres will fall out of production as water supplies tighten, and tensions over water supplies will only be exacerbated as the effects of climate change deepen…