In California, firefighters struggled to contain more than two dozen major fires as hot weather and gusty dry winds fanned existing flames and sparked new blazes overnight. The latest fires in Northern California’s Napa and Shasta counties have consumed some 10,000 acres, destroying wine vineyards and homes, and prompting evacuation orders.

As California enters the peak of its historic fire season, a record-shattering 3.4 million acres have already burned. Climate scientists warn greenhouse gas emissions have led to searing record heat and an enduring drought that’s dried out vegetation and left Californians vulnerable to explosive fires.

This comes as Stanford University researchers found at least 1,200 people — and as many as 3,000 — died as a result of inhaling toxic smoke that’s blanketed California in recent weeks.