California’s Wildfires Are an Ominous Sign

The unfortunate truth is that the massive wildfires raging in California are a “new normal” now. There will be more of these sorts of fires throughout the American west in the years and decades to come. There are lots of reasons why the historic, devastating California fires aren’t surprising, scientists have warned for years.

For instance, human-caused climate change is increasing wildfire activity across western forests. Since 1970, temperatures in the American West have increased by about twice the global average – and scientists have found a direct link between global warming and increased heat extremes over the western United States.

Scientists say that the effect of temperature – and how dry the vegetation is – can matter more for wildfire risk than how much rain or snow fell the previous winter. A warmer world has drier landscapes, and dry vegetation becomes fuel for fires making them more likely to spread farther and faster. From 1979 to 2015, climate change accounts for 55 percent of observed increases in land surface dryness in western forests.

There are any number of obvious climate signals in the California fires. Higher temperatures, drier conditions, increased fuel availability and lengthening warm seasons – all linked to climate change – are increasing wildfire risk. There has been a fourfold increase in the number of large and long-duration fires in the American West since 1980. Meanwhile, the length of the fire season in the west has increased by a whopping 2.5 months on average.

This dramatic change has the state’s politicians – and federal fire-fighting officials – genuinely worried. California is spending considerable amounts of money simply keeping the fires under control. In July, the state spent more than $114 million fighting eight fires (including the three record-setting fires that are generating headlines).

But extreme heat and heatwaves – both of which are starting to plague California and the west more frequently now – are also clear climate signals. Average temperatures in the American West have increased twice the global average since 1970. As the American West continues to heat up, conditions are primed for wildfires to ignite and spread.

All of this has firefighters in the region concerned about the immediate future. The Mendocino fire is unlike anything they’ve ever seen before.

“It is extremely fast, extremely aggressive, extremely dangerous. Look how big it got, just in a matter of days.… Look how fast this Mendocino Complex went up in ranking. That doesn’t happen. That just doesn’t happen,” Scott McLean, a deputy chief with the California Department of Forestry and Fire Protection, told the Los Angeles Times.

There are other ominous harbingers. California was record warm in July 2018 at 79.9°F. Death Valley had the hottest month on record observed anywhere at 108.1°F. California temperatures were as much as 10°F higher than normal in the months leading up to the Mendocino Complex fires.

There are more climate links to the deadly wildfires as well – involving complex factors like vapor pressure deficits, for instance – but the important point that matters is this: the massive, deadly fires we’re seeing in California right now can be explained by Earth’s changing climate system, scientists say. And the situation is likely to get worse before it gets better.