As the narrative of the Southern California wildfires has shifted to identifying the causes behind what could prove to be the most expensive natural disaster in U.S. history, a common refrain has emerged on social media that seeks to dismiss the role scientists say climate change played.

Extreme heat dries out vegetation and the soil. Wildfires ignite more easily, spread faster and burn with greater intensity in these conditions, as parched land is more flammable. In the western US, aridity caused by climate change has helped double the amount of combustible forest since 1984.

The California fires erupted amid extremely dry conditions. UCLA scientists say extreme heat linked to climate change was a factor in the fires' intensity.