Changes

What has changed is that since 2000 the scale of wildfires has now become far larger, even approaching some of the scales witnessed in pre-1800 data. In 2000, about 300,000 acres burned in total in the state of California. By 2018, the total was almost 2 million acres. In 2018, the Camp Fire was the most deadly wildfire in California's history, with 150,000 acres burned and 85 fatalities. It burned over 18,000 buildings and was the most expensive natural disaster in 2018, largely destroying the towns of Paradise and Concow. To date, the 2020 wildfires have consumed about 4 million acres, about the size of Connecticut, making 2020 the worst since historical records began. The August Complex fire, burning between San Francisco and Oregon, has consumed more than 1 million acres alone. Most large fires were under 100,000 acres previously. The most likely factors causing this trend is the fact the fire seasons is now historically longer than it was over the 20th century, when fires were relatively small. Additionally, many trees have also died over multi-year droughts, causing a larger fire hazard as dead trees are not cleared or left standing in forests. Climate change, undoubtedly as most scientists have concluded, is a key factor in this, as trees become dry, the rainy season is diminished, and tree mortality from insects that kill trees and that thrive in warmer temperatures increase. Fires have generally become less deadly, as warning systems have improved, although increased urbanization has also meant that fires can be more destructive, at least financially, than they have been historically. Overall, about 800,000 acres burn annually on average over the last 20 years. Additionally, fire suppression, while diminished from earlier in the 20th century, has still continued despite general policy shifts. This has meant that as forests do not burn as much from a year-to-year basis, at least in the recent past, fires are likely to be larger when they do burn, as there is more likely to be old growth and even dead trees left standing. This also appears to play some role in the large scale of recent fires. However, interestingly, the scale of fires is still more often less than estimates for annual fires and their size for the pre-1800 era.<ref>For more on recent trends affecting wildfires in California, see: van Wagtendonk, J.W., Sugihara, N.G., Stephens, S.L., Thode, A.E., Shaffer, K.E., Fites-Kaufman, J. (Eds.), 2018. <i>Fire in California’s ecosystems </i>, Second edition. ed. University of California Press, Oakland, California.</ref>