The years with the most acres burned by wildfires have some of the hottest temperatures, an Associated Press analysis of fire and weather data found. As human-caused climate change has warmed the world over the past 35 years, the land consumed by flames has more than doubled.

Experts say the way global warming worsens wildfires comes down to the basic dynamics of fire. Fires need ignition, oxygen and fuel. And what’s really changed is fuel — the trees, brush and other plants that go up in flames.

“Hotter, drier weather means our fuels are drier, so it’s easier for fires to start and spread and burn more intensely,” said University of Alberta fire scientist Mike Flannigan.

It’s simple, he said: “The warmer it is, the more fire we see.”

Federal fire and weather data show higher air temperatures are turbocharging fire season.

The five hottest Aprils to Septembers out West produced years that on average burned more than 13,500 square miles, according to data at the National Interagency Fire Center and the National Oceanic and Atmospheric Administration.

That’s triple the average for the five coldest Aprils to Septembers.

The Western summer so far is more than 3 degrees Fahrenheit warmer than the 20th century average. California in July logged its hottest month in 124 years of record-keeping.

Fuel moisture levels in California and Oregon are flirting with record dry levels, NOAA western regional climate center director Tim Brown said.