Is climate change driving blazes? Experts say no

Source: By Thomas Frank, E&E News reporter • Posted: Thursday, January 9, 2020

Climate change played a minor role in the wildfires that devastated California in the past three years, a panel of experts said yesterday, blaming most of the damage on land management and development.

Scott Stephens, a professor of fire science at the University of California, Berkeley, said 20% to 25% of the wildfire damage resulted from climate change, and “75% is the way we manage lands and develop our landscape.”

Jennifer Montgomery, director of the California Forest Management Task Force, said climate change “accelerated” wildfires by creating hotter and drier conditions throughout the state that intensified naturally occurring blazes.

“Climate change is an amplifier for natural systems and natural occurrences,” Montgomery said.

The comments by Montgomery and Stephens at an environmental conference in Washington undermine recent assertions by the head of California’s largest power utility that the wildfires were climate-driven.

From 2017 to 2019, California wildfires killed 103 people, burned nearly 4 million acres and caused millions of utility customers to lose power for weeks as electric companies shut off electricity to prevent downed power lines from igniting forests or grasslands.

The head of PG&E Corp., which runs California’s largest utility, told a Senate hearing last month that the wildfires were “a climate-driven experience” caused by extensive drought that has turned forests into tinderboxes.

California’s “prolonged, record drought; unprecedented tree mortality; heat waves;” and offshore “Diablo” winds created “a significant and an unforeseen increase in wildfires,” CEO Bill Johnson told the Senate Energy and Natural Resources Committee.

PG&E and subsidiary Pacific Gas and Electric Co. have accepted blame for the notorious 2018 Camp Fire, which killed 85 people and burned more than 150,000 acres in Northern California. A December report by California regulators said the utility “failed to maintain an effective inspection and maintenance program to identify and correct hazardous conditions on its transmission lines.”

Wildfire has a long history in California and until recently was a vital part of the state ecosystem, helping to thin forests. In the 18th century, when California was occupied by indigenous communities, wildfire burned about 4.5 million acres a year, said Stephens, the Berkeley professor.

In 2018 — when wildfires killed 100 people in California and destroyed nearly 25,000 structures — the fires burned 2 million acres. From 2013 through 2019, wildfires burned an average of 935,000 acres annually in California, according to the state Department of Forestry and Fire Protection.

“When you think about what fire used to do in the state, it was so integral to systems. Fire was almost as important as rain to ecosystems,” Stephens said.

Climate change today “is just another factor that causes increased drying and an increase in the fire season,” he added. “The fire season is longer because we have less snow on the ground and temperature increases. There’s no doubt that will continue.”

Although wildfires burn less acreage than they did hundreds of years ago, they are far more damaging because of both the amount of development in wildland-urban interface areas and the intensity of fires.

“Historically, we had 17% to 22% of our fires were high-intensity fires. The rest were beneficial. Lately, it’s been 50% or more that are high-intensity,” said Montgomery, the task force director who was appointed by Gov. Gavin Newsom (D).

One-quarter of California’s 40 million residents live in wildland-urban interface areas, Montgomery said.

“Wildfire is not really wildfire — it’s not pointy green trees,” she said. “You get these so-called wildfires at intersection of development.”

Both Montgomery and Stephens advocated thinning California’s forests, either through prescribed burns or manual clearing. They spoke yesterday at the annual conference of the National Council for Science and the Environment.