In 2000, researchers took a coring from the bed of a small, shallow lake in the Eastern Sierra Nevada mountains. They analyzed the organic matter and chemicals in the sediments to reconstruct a climate record of the past 10,000 years. They then compared it with reconstructions of ancient ocean temperatures. The results echoed previous studies that have found a link between past periods of climate warming, cool sea-surface temperatures in the eastern Pacific Ocean and centuries-long droughts in California and the West. Does that mean that global warming is pushing California to the threshold of endless drought?