Is climate change to blame for string of Southland fires?

Research has shown an increase in large wildfires in some western forest regions in recent decades, particularly in the northern Rocky Mountains and, to some extent, California's Sierra Nevada.

Warming is reducing the snowpack there and causing it to melt earlier, resulting in a longer, drier fire season.

But scientists say no definitive link has been demonstrated between rising temperatures and wildfire occurrence in Southern California's chaparral country.

In a statement after the firestorms that struck the region in October 2007, UC Merced assistant professor Anthony Westerling said that while there have been big wildfire years, no statistically significant fire trends are evident in the coastal chaparral belt.

"We can't finger climate change," said Dan Cayan, a climate researcher at Scripps Institution of Oceanography at UC San Diego.

The current drought in the Southwest may simply be part of the normal cycle of wet and dry spells, rather than a reflection of global warming.

But looking over the next century, Cayan said, regions with a Mediterranean climate such as Southern California are expected to get drier.

"That suggests longer and more intense droughts, and I have to believe that is going to make us more vulnerable to some of these more intense fire episodes."