The pandemic has reduced West Coast emissions. The fires have already reversed that.



That is far above normal levels this part of the year and comes on top of the sharp increase in emissions from mass fires across the American West in 2020. more than 100 million tons carbon dioxide last year, which was already enough to more than offset the annual drop in emissions in the wider region.

“Constant but slow decline [greenhouse gases] pale compared to fire, ”says Oriana Chegwidden, a climate scientist at CarbonPlan.

Massive fires burning on millions of hectares in Siberia are also clogging of the sky throughout eastern Russia and release tens of millions of tons of emissions, Copernicus reported earlier this month.

Fires and forest emissions are expected to increase in many regions of the world as climate change accelerates in the coming decades, creating hot and often dry conditions that turn trees and plants into clumps.

Fire risk – defined as the chance that an area will experience a fire of moderate to severe severity any year – could quadruple across the U.S. by 2090, even under scenarios where emissions fall significantly in the coming decades, according to a recent study researchers from the University of Utah and CarbonPlan. With unverified emissions, the U.S. fire risk could be 14 times higher by the end of the century.

Emissions from the fire “are already bad and will only get worse,” says Chegwidden, one of the study’s lead authors.

“Very ominous”

Over longer periods, the emissions and climate impacts of growing fires will depend on how fast forests grow and draw carbon – or whether they will at all. This, in turn, depends on the dominant trees, the severity of the fire and how much the local climatic conditions have changed since that forest took root.

While working on her doctorate in the early 2010s, Camille Stevens-Rumann spent the summer and spring months walking through the alpine forests at Iraq’s Frank-River Church of No Return Wilderness, studying the effects of fires.

She noticed where and when coniferous forests began to return, where they did not, and where opportunistic invasive species like the decoy took over the landscape.

U Study 2018 in the journal Ecology Letters, she and her co-authors concluded that the trees that burned over the Rocky Mountains had far more problems with growth this century as the region became hotter and drier than at the end of last. Dry coniferous forests that have already sprouted on the brink of surviving conditions were likely to simply turn into grass and shrubs, which generally absorb and store much less carbon.

That can be healthy to some extent, creating fire breaks that reduce damage from future fires, says Stevens-Rumann, an assistant professor of forest and pasture management at Colorado State University. It can also help make up for the American history of aggressive firefighting, which has allowed fuel to accumulate in many forests, while also increasing the chances of large fires when they catch fire.

But their findings are “very ominous” given the massive fires we are already seeing and projections for all the hot and dry conditions across the American West, she says.

Other research has noted that these pressures could begin to fundamentally transform U.S. western forests in the coming decades, damaging or destroying biodiversity resources, water, wildlife habitats, and carbon stores.

Fires, droughts, insect infestations and changing climatic conditions will turn major parts of California forests into shrubs, according to modeling study published in AGU Advances last week. Tree losses could be particularly large in the dense Douglas fir and coastal redwood forests off the coast of northern California and at the foot of the Sierra Nevada chain.

Kings Canyon National Park, in the Sierra Nevada area of ​​California, after a recent forest fire.


Overall, the state will lose about 9% of the carbon stored in trees and plants above the ground by the end of this century under a scenario in which we stabilize emissions this century, and more than 16% in a future world where they continue to grow.

Among other influences, this will obviously complicate the state’s reliance on its countries to capture and store carbon through it forestry compensation programs and other climate efforts, the study notes. California is aiming to make coal neutral by 2045.

Meanwhile, medium to high emission scenarios create a “real likelihood of turning Yellowstone forests into non-forest vegetation in the middle of the 21st century”, as more frequent and larger fires would make it increasingly difficult for trees to return, 2011 study in the Proceedings of the National Academy of Sciences concluded.

Global picture

The net effect of climate change on fires and fires on climate change is much more complicated globally.

Fires directly contribute to climate change by releasing emissions from trees, as well as rich carbon stored in soil and peatlands. They can also produce black carbon which can eventually settle on glaciers and ice sheets, where it absorbs heat. This accelerates the loss of ice and rising ocean levels.

But fires can also trigger negative climate feedback. The smoke of western forest fires that have reached the east coast in recent days, although terrible for human health carries aerosols which reflect a certain level of heat back into space. Similarly, fires in boreal forests in Canada, Alaska, and Russia, they can open up space for snow that reflects much more than the forests they have replaced, diminishing the warming effect of emissions.

Different parts of the world are also being pushed and pulled in different ways.

Climate change is exacerbating forest fires in most of the world’s forested areas, says James Randerson, a professor of ground systems science at the University of California, Irvine, and co-author of the AGU paper.

But the total area burned in fires around the world is it actually falls, primarily due to the reduction in the number of savannas and grasslands in the tropics. Among other factors, widespread farms and roads fragment the landscape in developing parts of Africa, Asia, and South America, acting as breaks for these fires. Meanwhile, growing herds of cattle are swallowing fuel.

Overall, global fire emissions account for about one-fifth of fossil fuel levels, although they are not rising abruptly more. But total emissions from forests have obviously climbed when you turn on fires, deforestation and deforestation. They rose from less than 5 billion tons in 2001 to more than 10 billion in 2019, according to data a Work on climate change in nature in January.

Less fuel to burn

As warming continues in the coming decades, climate change itself will affect different areas in different ways. While many regions will become hotter, drier and more prone to fires, some colder parts of the world will become more hospitable to forest growth, such as high currents of high mountains and parts of the Arctic tundra, Randerson says.

Global warming could also get to the point where it actually starts to reduce certain risks as well. If Yellowstone, California’s Sierra Nevada and other areas lose large portions of their forests, studies suggest, the fires could begin to disappear by the end of the century. This is because there will simply be more or less flammable fuel to burn.

It is difficult to make reliable predictions about global emissions of forests and fires in the coming decades because there are so many competing variables and unknowns, especially including actions people will choose to take, says Doug Morton, head of NASA’s Goddard Space Biosphere Science Laboratory. Flight Center.


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