California drought: Past dry periods have lasted hundreds of years, scientists say

[Jesus Malverde]

California's current drought is being billed as the driest period in the state's recorded rainfall history. But scientists who study the West's long-term climate patterns say the state has been parched for much longer stretches before that 163-year historical period began.

And they worry that the "megadroughts" typical of California's earlier history could come again.

Through studies of tree rings, sediment and other natural evidence, researchers have documented multiple droughts in California that lasted 10 or 20 years in a row during the past 1,000 years — compared to the mere three-year duration of the current dry spell.

The two most severe megadroughts make the Dust Bowl of the 1930s look tame: a 240-year-long drought that started in 850 and, 50 years after the conclusion of that one, another that stretched at least 180 years.

"We continue to run California as if the longest drought we are ever going to encounter is about seven years," said Scott Stine, a professor of geography and environmental studies at CSU East Bay. "We're living in a dream world."

California in 2013 received less rain than in any year since it became a state in 1850. And at least one San Francisco Bay Area scientist says that based on tree ring data, the current rainfall season is on pace to be the driest since 1580 — more than 150 years before George Washington was born. The question is: How much longer will it last?

A megadrought today would have catastrophic effects.

http://www.montereyherald.com/news/ci_24994179/california-drought-past-dry-periods-have-lasted-hundreds.html

[seattledo]

1. Does this meet the true, but false standard? ntxt

[Brother Buzz]

2. A stand of trees at the bottom Fallen Leaf Lake Support this theory

Inside an underwater forest frozen in time
Monday, March 28, 2011

LAKE TAHOE, Calif. (KGO) -- Scientists in the High Sierra have discovered a previously unknown forest, and there's a twist. The ancient trees in this forest are under water. They are standing at the bottom of Fallen Leaf Lake, just south of Lake Tahoe. New research shows both the forest and the lake hold critical clues to climate change.

Fallen Leaf Lake is already known for its spectacular beauty. Now it turns out the lake also has a dramatic secret.

"What I like to call a ghost forest," says Prof. Graham Kent of the University of Nevada, describing trees up to 100 feet tall, as high as a 10-story building, but covered by water. "We have old wood from a thousand years ago, 2,000, 3,000 down there."

Scientists in a small submarine took photos showing just a few of the hundred or more trees on the bottom of the lake. They're using state of the art sonar to map the mysterious forest and try to figure out why it's there.

<snip>

Researchers say all this evidence confirms that a thousand years ago there was a prolonged drought in the Sierra. It lasted about 200 years -- long enough for huge trees to grow where Fallen Leaf Lake now sits. The precipitation is believed to have been just 60 percent of normal. That is similar to the devastating midwest "Dust Bowl" in the 1930s. Scientists believe it may happen again.

<more>

http://abclocal.go.com/kgo/story?id=8039789

[itsrobert]

3. Or the land could have shifted

making a natural dam that filled the lake.

[Brother Buzz]

6. Maybe, just maybe, the fishing fool geology professor who made the initial discovery....

might have considered that.

Fallen Leaf is very sensitive to drought and begins to fall quickly. A slight (60% of normal) decline in precipitation causes the lake level to fall faster than other lakes because it drains through porous soil to Lake Tahoe below.

[Jesus Malverde]

5. cool lake and story thanks...nt

[democratisphere]

4. The drought will be solved with multi-billions spent on desalinization plants, conservation....

and much higher prices for water and things related. Global warming and climate change contributing to megadroughts will cost US megabillions.

[adieu]

7. Perhaps Jerry Brown

should work on desalination systems first before working on the bullet train to link SF and LA. Have a workable desalination system to provide water for the agriculture. Let the reservoir water be used for human consumption.