Wider LA Areas Will Be ‘more Flammable’ Due To Climate Change, Study Finds

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Scientists have warned wider areas of Los Angeles will become “more flammable” as temperatures rise, after finding the ferocious fires that killed at least 28 people and destroyed 16,000 buildings were made more than one-third worse by the conditions caused by climate change.

More than 30 researchers, including wildfire scientists from the US and Europe, calculated the hot, dry and windy weather that drove the LA fires would become another 35 per cent more likely if global warming reaches 2.6C above pre-industrial times. The world has already warmed by at least 1.1C.

The scientists, part of the World Weather Attribution group, combine weather data with climate models to understand the effects of climate change.

While it was not southern California’s “first rodeo when it comes to fires”, said John Abatzoglou, professor of climatology at the University of California Merced, the conditions provided the “perfect storm when it comes to conditions for fire disasters”.

Fires broke out on January 7 and were fanned by the powerful Santa Ana mountain winds. Exceptionally wet weather the previous winter had led to a rise in vegetation, but an extremely hot summer and a delay to the following rainy season meant the abundant plants were very dry.

The study found that low rainfall from October to December was about 2.4 times more likely compared with the pre-industrial climate, and fire-prone conditions had extended by about 23 days each year, increasing the chance a fire would start during peak Santa Ana winds.

Water infrastructure, not designed to fight a rapidly expanding wildfire, was unable to keep up with scale and extreme needs, it also noted.

UCLA hydroclimatologist Park Williams flagged the dangers faced by the many neighbourhoods in Southern California nestled in the heavily vegetated mountainsides, from Santa Barbara through Ventura, Orange and San Diego counties.

“I’d say that a large number of neighbourhoods are at similar risk to the small number of areas that we saw actually be exposed to the fires this year,” Williams said.

Recent days of rain in may have “paused” the spread of the fires, but not enough had fallen to be definitive. A further risk is posed by the possibility that severe rainfall on hardened and charred ground will result in landslides.

The study is the third since the fires broke out to find a link between climate change and the disaster. Last month, rapid research from scientists at UCLA said climate change could be blamed for about 25 per cent of the fuel available for the fires.

“Politicians are talking about mismanagement of the landscape, but that is not the case with these particular fires,” said UCLA’s Williams.

The researchers said that while the individual results showed some degree of uncertainty, the overall results pointed in the same direction, indicating that climate change caused primarily by the burning of fossil fuels had increased the likelihood of the fires.

“Without a faster transition away from planet-heating fossil fuels, California will continue to get hotter, drier and more flammable,” said Clair Barnes of Imperial College London.

The findings were not peer reviewed because of the rapid nature of the study, but other scientists backed the findings.

“WWA’s study uses widely employed methods in climate change attribution, considers long-term and immediate causes of the fire, and draws on multiple lines of evidence from weather observations and climate models to buttress their findings,” said Rupert Stuart-Smith, senior researcher in climate science and attribution at Oxford university.

“Fires in California are far from unprecedented, but, be it in the extremely dry autumn that created tinderbox conditions, or the fire weather that drove the rapid spread of the flames, the authors find fingerprints of human-caused climate change throughout this event.”