The Morning Report
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I just spoke to Tony Westerling, assistant professor of environmental engineering at University of California, Merced. He was a leading contributor to a 2006 Scripps Institution of Oceanography research paper that connected climate change to increasing fire frequency in the West.
He said the fires blazing through San Diego County now couldn’t be directly connected to human-influenced climate change.
The Scripps research paper drew a connection between climate change’s effects on the timing of spring in mountainous areas of the West. As the region warms, spring snowmelt happens sooner and can lead to a longer and earlier dry season. In higher mountainous areas, temperature has the most significant impact on the wildfire season.
In San Diego, though, the dry season is much longer than in areas such as the Rocky Mountains.
“This is when you get your fall fires and Santa Ana winds,” Westerling said. “It doesn’t have a lot to do with what we wrote our paper about.”
Questions remain about the effect climate change will have on future fire frequency in San Diego.
Scientists say that by 2100, coastal San Diego will grow at least 4 degrees Fahrenheit warmer as climate change continues. Inland, the increase is expected to be 8 degrees higher.
But models disagree about whether precipitation will increase or decrease — and that has a key influence on fire frequency.
If the region gets wetter weather, Westerling said fire risk increases in chaparral and grass ecosystems. Wet winters help plants grow and increase potential fuel sources.
If the region dries out, it would become less fire-prone, Westerling said, because there would be less to burn.