What role does it play in the California wildfires

High winds and a lack of rain are the main factors that cause wildfires in Southern California, but climate change is altering the background conditions, making these fires more likely, experts say.

Researchers have shown that global warming is increasing the number of “fire weather” days, when conditions are more suitable for wildfires to break out.

California is now particularly vulnerable due to the lack of rain in recent months after a very warm summer.

Strong Santa Ana winds, which are common this time of year, combined with dry conditions can lead to fast moving and dangerous fires.

These strong, dry winds of 60-70 mph are blowing from inland Southern California toward the coast, and this month has seen the area experience its worst strong winds in more than a decade.

The winds are drying out the land, and researchers say that while the strongest winds will occur at the beginning of this outbreak, the driest vegetation will appear at the end, meaning these fires could last quite a while.

High wind speeds also change the location of fires. Many outbreaks occur high in the mountains, but these recent fires have moved quickly into valleys and into more populated areas.

“There are more potential ignition sources here,” climate researcher Daniel Swain of the University of California, Los Angeles, said in a social media post.

“It’s also harder to shut down power proactively here than in other places where these public safety blackouts are more common and prepared for more regularly. So there will be some potential problems. “

The impact of climate change is evident in the bigger picture for the state.

California experienced a decade-long drought that ended just two years ago. As a result of the wet conditions, brush and trees have grown rapidly since then, making ideal fuel for fires.

However, last summer was very hot, followed by a fall and winter, with central Los Angeles seeing just 0.16 inches of precipitation since October, more than 4 inches below average.

Researchers believe that global warming is increasing conditions conducive to wildfires, including low relative humidity.

Those “fire weather” days are increasing in many parts of the world, and climate change is making those conditions more severe and the fire season longer in many parts of the world, scientists have shown.

In California, the situation is exacerbated by the terrain, with fires burning more intensely and moving faster on steep terrain. This area of ​​California is also dominated by native, highly fire-prone shrub vegetation.

“Although fires are a common and natural occurrence in this region, California has seen one of the largest increases in the length and extremes of the fire season in the world in recent decades, largely driven by climate change,” said Professor Stephan Doerr, director of the Center for Forest Fire Research at Swansea University.

“However, it is too early to say to what extent climate change has made these particular fires more extreme. This will need to be assessed in a more detailed attribution analysis.”