Drought in California. Floods in Colorado. Doubt, Now, in Scientists' Minds

Firefighters deliberately merged two major blazes in southeastern Australia on Oct. 22, 2013 in a desperate battle to manage the advancing infernos as weather conditions worsen. Photographer: William West/AFP via Getty Images
Lock
This article is for subscribers only.

By now, smart shoppers know that “natural” flavors and "artificial" flavors overlap in ways that challenge the meaning of the word natural.

Something similar is happening to the weather. Every year, scientists dissect extreme events for their natural causes and any trace of manmade global warming. A new report put out jointly by American and British scientists tours some of the most extreme weather of 2013, and finds climate change lurking behind some of them. Asian heat and storms had a boost from global warming. If California's drought, Colorado's flooding and the U.K.'s extreme cold also did, scientists haven't found it yet.