California’s drought was spawned by natural weather variations that have bedeviled the West throughout recorded history.
But a new study released Thursday says human-caused global warming is the worse natural phenomenon. The study by Columbia University’s Earth Institute isn’t the first to say warming has played a key role in dry conditions that plague California, but it’s the first to measure its impact, predicting that it increased the problem by as much as 25 percent.
Natural weather patterns that push away atmospheric moisture that carries rain is normal for the state. But warming adds to the resulting dryness and heat. A small amount of moisture stored in plants and the soil evaporates into the drier atmosphere.
“A lot of people think that the amount of rain that falls out the sky is the only thing that matters,” said Park Williams, a bio-climatologist at Columbia University’s Lamont-Doherty Earth Observatory who was the study’s lead author. “But warming changes the baseline amount of water that’s available to us, because it sends water back into the sky.”
Lightning strikes on parched earth are igniting wildfires all over the state. There are so many blazes that firefighters from across the world are rushing to help put them out.