Science Says: Hotter weather turbocharges US West wildfires

Science Says: 'The warmer it is, the more fire we see'
In this Aug. 7, 2018 file photo, firefighters monitor a backfire while battling the Ranch Fire, part of the Mendocino Complex Fire near Ladoga, Calif. 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 in flames has more than doubled. (AP Photo/Noah Berger)

As temperatures rise in the U.S. West, so do the flames.

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 (35,000 square kilometers), 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 (1.7 degrees Celsius) warmer than the 20th century average. California in July logged its hottest month in 124 years of record-keeping.

The five years with the most acres burned since 1983 averaged 63.4 degrees from April to September. That's 1.2 degrees warmer than average and 2.4 degrees hotter than the years with the least acres burned, AP's data analysis shows.

In California, the five years with the most acres burned (not including this year) average 2.1 degrees warmer than the five years with the least acres burned.

A degree or two may seem like not much, but it is crucial for fuel. The hotter it is, the more water evaporates from plants. When fuel dries faster, fires spread more and burn more intensely, experts said.

For every 1.8 degrees Fahrenheit that the air warms, it needs 15 percent more rain to make up for the drying of the fuel, Flannigan said.

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

Science Says: 'The warmer it is, the more fire we see'
In this April 30, 2018 file photo, firefighter Mike Sugaski packs his gear in his garage in Salida, Colo. The veteran firefighter used to think a fire of 10,000 acres was big. Now he fights fires 10 times as large. "You kind of keep saying 'How can they get much worse?' But they do." (AP Photo/Peter Banda)

And low humidity is "the key driver of wildfire spread," according to University of Colorado fire scientist Jennifer Balch who says the Western U.S. soon will start to see wildfires of 1 million acres (1,562 square miles).

Veteran Colorado hotshot firefighter Mike Sugaski used to consider 10,000-acre (16-square-mile) fires big, now he fights ones 10 times that or more.

"You kind of keep saying, 'How can they get much worse?' But they do," Sugaski said.

The number of U.S. wildfires hasn't changed much over the last few decades, but the area consumed has soared.

"The year 2000 seemed to be some kind of turning point," said Randy Eardley, the fire center's chief spokesman.

From 1983 to 1999, the United States didn't reach 10,000 square miles burned annually. Since then, 10 years have had more than 10,000 square miles burned, including 2017, 2015 and 2006 when more than 15,000 square miles burned.

Some people who reject mainstream climate science point to statistics that seem to show far more acres burned in the 1930s and 1940s. But Eardley said statistics before 1983 are not reliable because fires "may be double-counted, tripled-counted or more."

Nationally, more than 8,900 square miles (23,050 kilometers) have burned this year, about 28 percent more than the 10-year average as of mid-August. California is having one of its worst years.

Scientists generally avoid blaming global warming for specific extreme events without extensive analysis, but scientists have done those extensive examinations on wildfire.

John Abatzgolou of the University of Idaho looked at forest fires and dry conditions in the Western United States from 1979 to 2015 and compared that to computer simulations of what would be expected with no human-caused climate change. He concluded that global warming had a role in an extra 16,200 square miles (42,000 square kilometers) of forests burning since 1984.

A study of the 2015 Alaska fire season—the second biggest on record—did a similar simulation analysis, concluding that climate change from the burning of coal, oil and gas increased the risk of the fire season being that severe by 34 to 60 percent.

One 2015 study said globally fire seasons are about 18.7 percent longer since 1979. Another study that year says climate change is increasing extreme wildfire risk in California where wildfires already are year-round.

Also, drought and bark beetles have killed 129 million trees in California since 2016, creating more fuel.

Contrary to fire scientists, Interior Secretary Ryan Zinke this week told Breitbart radio that "what's driving" increased wildfires is an increase in fuel. He said the government has "been held hostage by environmental terrorist groups" that oppose clearing dead trees that they say provide wildlife habitat. Zinke, however, has acknowledged that climate change was a factor in worsening wildfires.


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Aug 20, 2018
No, "science" says no such thing. Seth Borenstein says it.

Historical wildfire data in the U.S. show essentially no correlation to temperatures beyond the obvious one: wildfires happen more in the summer in the Southwest because it's hotter and drier than winter, when there's more precipitation. See for yourself here:

https://www.nifc....res.html

Drought and dry conditions are WEATHER phenomena caused by regional persistent high pressure systems, not by global warming. Drought is a common occurence in the southwest U.S. and has been for thousands of years, influenced heavily by ocean and atmospheric circulation patterns in the Pacific Ocean. El Niño is a well-known example.

Additionally pine bark beetle outbreaks across the Southwest have killed millions of trees, creating fuel for wildfires. The outbreak is exacerbated by poor forest management, warm temperatures and long periods of drought.

Aug 20, 2018
Historical wildfire data for the U.S. shows much more acreage burned in the early 20th century than in the last couple decades.

https://www.nifc....res.html

The biggest fires in U.S. history happened in the early 20th century, for example:

https://en.m.wiki..._of_1910

Over the last century there is no trend of increasing acreage burned, and certainly no correlation to global temperatures, which should be no surprise because drought has nothing to do with global temperatures as explained above.

In California, the number of wildfires (but not the overall acreage burned) has actually gone down over the last 40 years:

https://www.ocreg...ing-down

Megadroughts were much bigger and more frequent in the Soutwest hundreds of years ago:

https://physicsto...T.3.3997

Aug 20, 2018
And finally this, from UC Berkeley professor of environmental science, John Battles:

we also know from previous research that a century of fire suppression has contributed to a potentially unsustainable buildup of vegetation. This buildup provides abundant fuel for fires

See https://phys.org/...med.html

It appears that Interior Secretary Ryan Zinke's comments about forest management contributing to larger wildfires are scientifically accurate.

Aug 20, 2018
Only a fool would look at raw data without also looking at the context for that data. Your fact that the biggest fires occurred in the early part of the 20th century ignores the fact that attitudes towards forest fires and techniques for fighting them have changed over the years. From your link about the Great Fire:
Influenced by the devastation of the Big Blowup, Silcox promoted the "10 a.m." policy, the goal of suppressing all fires by 10 a.m. of the day following their report.

That was in the 30s. (Didn't you bother to read your link?) Aerial firefighting didn't become effective until the mid-50s, about when the number of acres really started to drop. Of course, they've increased since the 2000s, as your chart showed, so maybe something is affecting them? Like temperature increases.

Aug 20, 2018
Drought and dry conditions are WEATHER phenomena caused by regional persistent high pressure systems, not by global warming.

There are two things wrong with this claim. First, there is a great deal of evidence that climate change/global warming has increased blocking patterns (https://www.resea...ents.pdf ). This means that high pressure systems are more persistent -> more drought.

Second, there are 2 things that cause droughts: less water and more heat. Heat evaporates what water there is, so if there's more heat, you should expect more drought (unless rain increases). At the very least, more heat exacerbates any drought.

Aug 20, 2018
From your comment:
Additionally pine bark beetle outbreaks across the Southwest have killed millions of trees, creating fuel for wildfires. The outbreak is exacerbated by poor forest management, WARM TEMPERATURES and long periods of drought.

(emphasis mine)
So your own comment indicates that increased temperatures will lead to worse forest fires. It's not enough that you don't read your own links, you also can't even be bothered to read your own comments.

Aug 20, 2018
Only a fool would look at raw data without also looking at the context for that data. Your fact that the biggest fires occurred in the early part of the 20th century ignores the fact that attitudes towards forest fires and techniques for fighting them ....HAWW...HEE...HAWW...HEE
That was in the 30s. (Didn't you bother to read your link?) Aerial firefighting didn't become effective until the mid-50s, about when the number of acres really started to drop. Of course, they've increased since the 2000s, as your chart showed, so maybe something is affecting them? Like temperature increases.

Uh huh...a fool....but it would take a JACKASS like you to argue, against factual data, with just conjecture.

Aug 20, 2018
Uh huh...a fool....but it would take a JACKASS like you to argue, against factual data, with just conjecture.


And only an idiot with an agenda that does not understand context, would be able to so completely misinterpret factual data.

Aug 20, 2018
Uh huh...a fool....but it would take a JACKASS like you to argue, against factual data, with just conjecture.


And only an idiot with an agenda that does not understand context, would be able to so completely misinterpret factual data.

Another Chicken Little Jackass HAWW...HEES.
These Chicken Littles "understands" context like they do science, they wouldn't know it, even if it slapped them on their jackass faces.
Why don't you share some of that context, instead of HAWW...HEEING......JACKASS.

Aug 20, 2018
Screaming nasties across the playground does not impress professionals.

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