One year of wildfires undid decades of California’s emissions policy
The fires were responsible for 23% of the state’s emissions in 2020.
One year of wildfires undid decades of California’s emissions policy
The fires were responsible for 23% of the state’s emissions in 2020
Oct 19th 2022
The visible physical damage wrought by forest fires is plain to see. But they have a further, invisible cost that is not as frequently quantified as the number of lives and value of properties lost. Trees and other vegetation extract carbon from the air. When they go up in flames, the carbon stored within their woody cells combines with oxygen to once more form carbon dioxide—adding to the environmental toll of the fires. “Dust to dust”, the saying goes. For trees, it is “gas to gas”.
This cycle means that raging wildfires are a considerable and often ignored source of emissions, and a growing one, too. In California, according to a new analysis published in Environmental Pollution, a journal, wildfire emissions are estimated to have wiped out the benefits of more than a decade of efforts to reduce emissions from energy, homes, waste, transport and industry (see chart).
Source: “Up in smoke: California's greenhouse gas reductions could be wiped
out by 2020 wildfires”, by M. Jerrett, A.S. Jina and M.E. Marlier, October 2022
*2020 non-wildfire emissions are assumed to be equal to 2019
Hotter, drier conditions due to climate change are increasing the extent of wildfires in the Golden State; the multi-year mega-drought has turned large swathes into a tinderbox. According to the California Air Resources Board (CARB), the state’s air-pollution regulator, the area burned during each fire season has steadily increased since 1950. Of the 20 largest fires measured since records began in 1932, 12 of them took place after 2016. The worst season so far was in 2020, when 1.7m hectares burned.
Michael Jerrett of the University of California, Los Angeles and his colleagues used fire data from CARB and two other sources to estimate the volume of greenhouse gases produced by wildfires each year. Between 2003 and 2019, that ranged between 15m and 22m tonnes of gases annually. In 2020 the figure jumped to 127m tonnes. That is 30% of the state’s total emissions from power, transport, buildings, industry, waste and agriculture in 2019, the last year for which such data are available. It is also half of the emissions budget that the state has set itself for 2030 as part of its climate targets.
Some of this carbon will be reabsorbed as vegetation regrows. But that process will take decades or more, during which time the gases will contribute to global warming and increase the likelihood of further fires. It would make sense, then, for wildfire emissions to be accounted for in the state’s emissions inventories.
More startling still is the comparison with the gains that have been achieved through California’s famously progressive decarbonisation policies. Between 2003 and 2019, the state’s emissions fell by 13%, mostly as a result of the expansion of renewable power generation at the expense of fossil fuels. As a result, 65m tonnes of greenhouse gases that might otherwise have been emitted over those 17 years were not. But in 2020 a single fire season emitted twice as much. Though the emissions data are not yet in, 2021 only worsened the situation, with a further 1m hectares burned. Countries and regions that are prone to burning and wish to reduce their emissions should consider how to manage the flames as well as their industry.■
https://www.economist.com/graphic-detail/2022/10/19/one-year-of-wildfires-undid-decades-of-californias-emissions-policy