News and Features

Few things are more important to California’s water supply than the water content of the mountain snowpack at the start of the state’s warm season. In the latest round of our Climate Challenge game, experts and participants predicted the water content of the Sierra Nevada snowpack on May 1, 2015. The answer was disturbingly low.

For 800,000 years before the twentieth century, carbon dioxide levels in Earth’s atmosphere never exceeded 300 parts per million. In March 2015, the monthly average went above 400 ppm for the first time.

At the end of April 2015, almost 60 percent of Oklahoma was experiencing moderate to exceptional drought, and 30 percent of Texas was experiencing drought conditions. But according to the May drought outlook, conditions are likely to improve in the southern Plains this month. 

How much warmer or colder than average would sea surface temperatures be in the eastern tropical Pacific Ocean in April 2015? That's the question we asked participants to answer in our new online game, in which players pit their predictive powers against experts’ opinions. The answer is in...

Strong evidence suggests that mountain areas are warming more quickly than lower elevations—with serious consequences for water supplies. But historical weather observations from mountain ranges are limited, leaving scientists with plenty of questions.

A new analysis suggests that in the winter following a La Niña, dryness in California often deepens into drought.  Consistent with that pattern, California’s current drought began in 2011-12, during the second year of a La Niña episode.