What role does it play in the fires in California
High winds and a lack of rain are the main factors driving 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 fires to start.
California is particularly vulnerable right now due to the lack of rain in recent months, after a very warm summer.
The strong Santa Ana winds that naturally occur this time of year, combined with dry conditions, can result in fast moving and dangerous fire outbreaks.
Reaching 60-70 mph, these strong, dry winds blow from inland Southern California toward the coast and this month has seen the worst high winds for the area in more than a decade.
Winds are drying out the land, and researchers say the strongest winds will be at the beginning of this outbreak and the driest vegetation will be at the end, meaning these fires could last for some time.
High wind speeds also change the location of fires. Many outbreaks occur high in the mountains, but these recent fires have moved quickly into the valleys and into areas where more people live.
“There are multiple potential ignition sources out there,” climate researcher Daniel Swain of UCLA said in a social media post.
“It’s also more difficult to preemptively shut down power there than in other locations where these public safety blackouts are more frequent and prepared for more regularly. So there will be some potential challenges there.”
The impact of climate change is visible in the wider picture of the country.
California experienced a decades-long drought that ended just two years ago. Since then, the wet conditions have led to the rapid growth of brush and trees, perfect fuel for wildfires.
However, last summer was very hot and was followed by a dry fall and winter season – downtown Los Angeles has only received 0.16 inches of rain since October, more than 4 inches below average.
Researchers believe global warming is increasing conditions that favor wildfires, including low relative humidity.
These “fire weather” days are becoming more common 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 topography, with fires burning more intensely and spreading faster on steep terrain. This area of California is also dominated by bushy vegetation that is naturally very fire prone.
“Although fires are frequent and natural in this region, California has experienced some of the most significant increases in the length and extremes of fire seasons globally in recent decades, largely driven by climate change,” said Professor Stefan Doerr, Director of the Center for Wildfire Research, at Swansea University.
“However, it is too early to say to what extent climate change has made these specific fires more extreme. This will need to be assessed in a more detailed attribution analysis.”