CO2: Forest fires destroy corona savings

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The forest fires that raged the west coast of the United States have now released so much carbon dioxide into the air that more than half of the pandemic-induced emissions reductions in the region last year were undone. And that was just July. The numbers illustrate a worrying feedback loop: Climate change is leading to hotter and drier conditions, increasingly leading to devastating fires, which in turn release greenhouse gases that further fuel warming.

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The problem is likely to get worse in much of the world in the coming decades. Not only does this mean that deadly fires will take ever greater tolls on communities, rescue workers, air quality, human health and forests, but also that they could undermine our very limited progress in combating climate change.

According to the Carbon Monitor In California, Idaho, Oregon and Washington, fossil fuel emissions fell by around 69 million tons of carbon dioxide last year as the pandemic reduced emissions from road traffic, aviation and industry. However, from July 1 to July 25, the fires in these states released about 41 million tons of carbon dioxide, according to data from the European Commission’s Copernicus Atmosphere Monitoring Service, available from MIT Technology Review.

That is well above normal values ​​for this time of year and on top of the increase in emissions caused by the great fires in the American West in 2020. The fires in California alone were made last year more than 100 million tons of carbon dioxide released, which was already enough to more than offset the annual decrease in emissions across the region. “The steady but slow reduction in [Treibhausgas-Emissionen] pale in comparison to those caused by forest fires, “says Oriana Chegwidden, climate scientist at CarbonPlan.

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Massive forest fires that span millions of hectares in Siberia are also darkening and setting the skies over eastern Russia Tens of millions of tons free of emissions, as Copernicus reported earlier this month. Fires and emissions from forests are expected to increase in many regions of the world as climate change could accelerate in the coming decades. Fire risk – defined as the likelihood that a moderate to severe fire will break out in an area in a given year – could be in the United States Quadruple by 2090even if emissions drop significantly in the coming decades, according to a recent study by researchers from the University of Utah and CarbonPlan. With emissions unchecked, the risk of fire in the US could be 14 times higher by the end of the century.

More from MIT Technology Review

More from MIT Technology Review

More from MIT Technology Review

“The emissions caused by fires are already bad today and will only get worse,” says Chegwidden from the study team. Over longer periods of time, the emissions and climate impacts of increasing forest fires will depend on how quickly the forests regrow and bind carbon – or whether they still do so at all. This in turn depends on the tree species, the severity of the forest fires and how much the local climatic conditions have changed since the forest was formed. During her PhD in the early 2010s, Camille Stevens-Rumann spent the summer and spring months wandering through the woods in Idaho’s Frank Church-River of No Return Wilderness conservation area, studying the consequences of fires. She noted where and when coniferous forests reappeared and where not, and where opportunistic invasive species such as ragweed were invading the landscape.

In a study published in the journal Ecology Letters in 2018, she and her co-authors concluded that trees that had burned down in the Rockies – in this century when the region has become hotter and drier – had far greater problems growing back than at the end of the last century. Arid coniferous forests, which were already on the verge of survival, were much more likely to turn into grass and shrubland, which in general take up and store much less carbon.

This can be healthy to some extent because it creates firebreaks that reduce damage from future fires, says Stevens-Rumann, assistant professor of forest and pasture management at Colorado State University. This can also help offset a bit of the aggressive firefighting in the United States, which grotesquely has resulted in the build-up of combustible material in many forests, which in turn increases the likelihood of major fires if it ignites. However, the study’s results are “very ominous” given the massive fires we’re already seeing – and rising temperature projections for the American West, she says.

Other studies have found that forests in the western United States could change fundamentally in the coming decades, damaging or destroying reservoirs for biodiversity, water, wildlife habitat, and carbon storage. Fires, droughts, insect infestations and changing climatic conditions will turn large parts of California’s forests into bushland, such a model study published in AGU Advances last week. The loss of trees could be particularly great in the dense Douglas fir and coastal mammoth forests along the northern California coast and in the foothills of the Sierra Nevada.

All in all, by the end of this century, the state will shed about 9 percent of the carbon stored above ground in trees and plants if we stabilize emissions this century – and more than 16 percent if they continue to rise in the future. Meanwhile, medium to high emission scenarios “have a real likelihood that Yellowstone forests will be converted to non-forest vegetation in the mid-21st century” as more frequent and larger fires would make it harder for the trees to grow back, such a study from 2011 in the Proceedings of the National Academy of Sciences. And what you see in America, you also see in Europe – from Greece to Brandenburg.


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