At 2 p.m. Friday on the day after Thanksgiving President Trump’s administration released an important document about our climate. Required every four years by a 1990 act of Congress, the Fourth National Climate Assessment focuses on the human welfare, societal, and environmental elements of climate change.
Surprising in its bluntness, it lays out the devastating effects on the economy, health, environment, and wildfires. Within the 1,656-page document wildfires are covered rather extensively and photos of fires are used several times in the headers of sections, like the one below for Chapter 1 (which may have been taken at the Howe Ridge Fire in Glacier National Park in Montana in August).
The scientists concluded that by the middle of this century, the annual area burned in the western United States could increase 2–6 times from the present, depending on the geographic area, ecosystem, and local climate. The area burned by lightning-ignited wildfires could increase 30 percent by 2060.
In the Southeast rising temperatures and increases in the duration and intensity of drought are expected to increase wildfire occurrence and also reduce the effectiveness of prescribed fire. Intra-annual droughts, like the one in 2016, are expected to become more frequent in the future. Thus, drought and greater fire activity are expected to continue to transform forest ecosystems in the region.
In the Southwest, recent wildfires have made California ecosystems and Southwest forests net carbon emitters (they are releasing more carbon to the atmosphere than they are storing). With continued greenhouse gas emissions, models project more wildfire across the area. Under higher emissions, fire frequency could increase 25%, and the frequency of very large fires (greater than 5,000 hectares) could triple.
The Northwest is likely to continue to warm during all seasons under all future scenarios, although the rate of warming depends on current and future emissions. The warming trend is projected to be accentuated in certain mountain areas in late winter and spring, further exacerbating snowpack loss and increasing the risk for insect infestations and wildfires. In central Idaho and eastern Oregon and Washington, vast mountain areas have already been transformed by mountain pine beetle infestations, wildfires, or both, but the western Cascades and coastal mountain ranges have less experience with these growing threats. Forests in the interior Northwest are changing rapidly because of increasing wildfire and insect and disease damage, attributed largely to a changing climate. These changes are expected to increase as temperatures increase and as summer droughts deepen.
Below are wildfire-related excerpts from the report.
Chapter 1: Overview
The impacts of climate change and extreme weather on natural and built systems are often considered from the perspective of individual sectors: how does a changing climate impact water resources, the electric grid, or the food system? None of these sectors, however, exists in isolation. The natural, built, and social systems we rely on are all interconnected, and impacts and management choices within one sector may have cascading effects on the others.