Last week, 18 wildfires were burning at once in California, including its largest in history, destroying over 1,100 homes and forcing tens of thousands of residents to evacuate. The smoke made the air in the state’s Central Valley unhealthy to breathe for a record 15 consecutive days, as I can personally attest.

Dr. Daniel Swain (@Weather_West) Fun fact: there are currently no clouds at all over NorCal. The opaque skies from #SanFrancisco to #Sacramento to #Redding to #Lake Tahoe are the exclusive product of dense #smoke from numerous large #wildfires. #CarrFire #RanchFire #DonnellFire #FergusonFire #CAfire #CAwx pic.twitter.com/feVtfkDJTT

Donald Trump decided to use the opportunity to renew his war with California by nonsensically blaming the wildfires on environmental laws.

Donald J. Trump (@realDonaldTrump) California wildfires are being magnified & made so much worse by the bad environmental laws which aren’t allowing massive amounts of readily available water to be properly utilized. It is being diverted into the Pacific Ocean. Must also tree clear to stop fire from spreading!

It’s no surprise that Donald Trump dislikes California. His 2.9m national popular vote deficit to Hillary Clinton is a sore spot, and her margin of victory in California was by 30% and 4.3m votes. California has also long been a leader in developing laws to clean and protect the environment, and Trump despises regulations that benefit public health and welfare at the expense of industry profits.

And so, we got the Tweet bemoaning water being “diverted into the Pacific Ocean” (in scientific terms, they’re called “rivers”). Daniel Berlant, assistant deputy director of Cal Fire immediately noted that water isn’t firefighters’ problem:

We have plenty of water to fight these wildfires, but let’s be clear: It’s our changing climate that is leading to more severe and destructive fires

Climate change is making wildfires bigger

Although Rep. Doug LaMalfa (R-CA), who represents the district encompassing Redding (or what’s left of it) denied the reality of human-caused climate change in an interview with the Guardian, the scientific research clearly shows that global warming is exacerbating wildfires. As one might expect, hotter, drier conditions lead to bigger fires. Zeke Hausfather showed in an analysis for Carbon Brief that there’s a strong correlation between temperatures and the total area of forests burned in the western USA.

Facebook Twitter Pinterest Red bars show western US forest area burned (in thousand hectares) using data provided by Prof John Abatzoglou, updated from the data used in Abatzoglou and Williams (2016). Black line shows March-August temperature anomalies relative to a 1961-1990 baseline period for the US west of 102 degrees longitude using data from NOAA. Illustration: Zeke Hausfather, Carbon Brief

A 2016 study in the Proceedings of the National Academy of Sciences found that 75% of year-to-year variations in area burned by wildfires in the western US can be explained by fuel aridity (a combination of temperature and precipitation), and:

Anthropogenic climate change accounted for ∼55% of observed increases in fuel aridity from 1979 to 2015 across western US forests … and doubled the cumulative forest fire area since 1984

July 2018 was the hottest month ever recorded in California. The past four years were the state’s four hottest, and 2018 is on pace to also finish in California’s top-five hottest years. Plus, California just recently emerged from its worst drought in over a millennium, which was likewise amplified by global warming and created plentiful wildfire fuel.

Facebook Twitter Pinterest California average annual temperature data from Noaa (blue) and linear trend (red). Illustration: Dana Nuccitelli

Other factors like forest management have also played a role in the growing size of wildfires, but human-caused climate change is clearly a major contributor. Under a high-emissions global warming scenario, a 2011 study found that by the end of the century the annual area burned by wildfires in California would increase by about 50%, and would double in heavily-forested Northern California.

It’s also worth noting that forest management is primarily a federal, not state issue, headed by the Department of Interior and US Forest Service. As the Sacramento Bee reported:

The Trump administration’s own budget request for the current fiscal year and the coming one proposed slashing tens of millions of dollars from the Department of Interior and U.S. Forest Service budgets dedicated to the kind of tree clearing and other forest management work experts say is needed.

Ironically, California has been using the $256m allocated to wildfire risks from the state’s carbon cap and trade system revenues. Visiting the state yesterday, Trump’s Interior Secretary Ryan Zinke said:

It doesn’t matter whether you believe or don’t believe in climate change. What is important is we manage our forests.

But given that global warming doubled the area burned by forest fires over the past three decades, it really does matter that the Trump administration denies climate change and is actively making the problem worse.



California is fighting climate change. Trump is fighting California



Meanwhile, California and the Trump EPA are battling over vehicle fuel efficiency standards, which had not improved for decades until the Obama administration took office and bailed out the American auto industry, whose gas guzzlers became unpopular when gasoline prices spiked.

brad plumer (@bradplumer) Transportation was the most obvious example. We let CAFE standards stagnate from 1980 to 2010. As @KnittelMIT has shown, automakers kept improving engine technology during that time, but used it to build bigger, more powerful vehicles instead of improving fuel economy. /4 pic.twitter.com/UxKSbEwJQr

The EPA has tried to justify freezing the standards by claiming more fuel efficient cars will cost consumers money by increasing new vehicle prices, and will thus also increase road deaths, because fewer Americans will buy newer, safer cars. This is some tortured logic. Were fewer Americans to buy new cars, they would save money, especially since those buying new vehicles would save thousands of dollars in gasoline costs over their lifetimes. And Trump is also planning to launch tariffs on imported autos and auto parts that will raise the costs of new cars sold in America by thousands of dollars.

Moreover, particulate matter (to which vehicles are a major contributor) causes up to 30,000 premature American deaths per year. Decreasing this pollution by increasing fuel efficiency will save lives. The Trump administration denies this reality by claiming that some pollution is just fine. Although the scientific research has shown that there is no known safe level of particulate matter, the EPA has begun to assume cutting the pollution below a certain threshold produces no health benefits. The Trump EPA even hired a scientist who has argued that the air in America is “a little too clean for optimum health.”

California is fighting the Trump EPA’s efforts to weaken the fuel efficiency standards “in every conceivable way possible,” and is likely to win the legal battle. The California Air Resources Board unveiled a proposal last week that would require any new car sold in California to comply with California’s regulations regardless of what the federal government says.

CARB (@AirResources) California moves to ensure vehicles meet existing state greenhouse gas emissions standards



Action comes in response to Trump Administration effort to roll back federal rules ➡️ https://t.co/dszgO7H5s5 #CleanCarStandards pic.twitter.com/xeR59EkAfF

And last year, California extended its carbon cap and trade system through 2030 with some bipartisan support from state lawmakers. But now the Trump administration wants to open more public land in California to fracking and oil drilling.

In short, climate change is degrading the quality of life in California, and while the state is showing great leadership in trying to mitigate the problem, the Trump administration is doing everything in its power to make it worse in order to maximize polluter profits.