Story at a glance

  • Wildfires in California are getting bigger and more frequent.
  • As climate change heats the planet, big, destructive fires become more likely, according to scientists.

Climate change has a history of being presented as something squishy and equivocal by those who seek to undermine its reality. But fire is hard to argue with. 

This year, last year and the year before that, California has caught fire — billowing smoke and soot visible from space. And despite the partisan politics surrounding climate change, nobody has demanded recounts of the thousands of acres that have burned or the homes the flames have reduced to ash.

California has always had fire, yes, but not like this. The acres charred by wildfire each year in California have increased by 500 percent since 1972, and 15 of the 20 largest fires in the state’s history have occurred since 2003

Across national forests in the western U.S., wildfires that burn more than 10,000 acres have increased sevenfold since 1970 and the total area burned has doubled to exceed 2 million acres — an area the size of Yellowstone National Park. Fire season has also increased by two and a half months.

The rampant burning of fossil fuels during roughly this same timeframe (actually just the last 30 years) has released more than half of all the carbon dioxide humans have added to the atmosphere since the industrial revolution. Carbon dioxide is called a greenhouse gas because it traps heat, and as people have filled the atmosphere with more and more of it, the planet has gotten hotter. 

According to NASA, Earth’s average temperature has gone up about 1.4 degrees Fahrenheit (0.8 degrees Celsius) since 1880, and two-thirds of that warming has been packed into the last 40 years. Humans are driving this change in the planet’s climate. 

Climate change can’t directly cause individual fires, but can make them more likely. The study that showed the area burned by California’s wildfires was increasing also found that virtually all of that increase was driven by warming, especially in the summer months.

These hot, dry conditions are consistent with models of climate change, and they are turning California’s already fire-prone landscape into a tinderbox waiting to burst into flame. Cranking up the heat is also what’s extending fire seasons — winter snow is melting off earlier, and wet weather is coming later. 

Apart from climate change, humans have also made fires worse by suppressing them for decades and by living closer to forests. This has resulted in an excess of vegetation for fires to burn and more fire-starting sparks from human activity.

“No matter how hard we try, the fires are going to keep getting bigger, and the reason is really clear,” climate scientist Park Williams told Columbia University’s Center for Climate and Life

“Climate is really running the show in terms of what burns. We should be getting ready for bigger fire years than those familiar to previous generations.”

Published on Nov 15, 2019