A “potential connection” between anthropogenic global warming and the frequency or intensity of wildfires in California has yet to emerge in the trend observations.
Scientists have found a “lack of correlation between late summer/autumn wildfires” and “summer precipitation or temperature” in coastal California. In fact, “there is no long-term trend in the number of fires over coastal California” in the last 50 years (Mass and Ovens, 2019).
Image Source: Mass and Ovens, 2019
Fire history in the Western USA has recently declined to the lowest point in the last 1,400+ years (Marlon et al., 2012).
Image Source: Marlon et al., 2012
As CO2 concentrations have risen from 300 ppm to 400 ppm (1900 to 2007), the decline in global burned area has been significant (Yang et al., 2014).
Image Source: Yang et al., 2014
The falling trends in global-scale wildfires can even be dectected over the short-term 2001-2016 period (Earl and Simmonds, 2018).