The pandemic reduced emissions from the West Coast. The fires had already been reversed.

This part of the year is above the normal level, and in 2020 comes above the increase in massive fires in Western America. Only California fires are produced More than 100 million tons carbon dioxide last year was already more than enough to reverse the region’s declining annual emissions.

“Stable but slow declines [greenhouse gases] pale compared to those caused by fires, ”says Oriana Chegwidden, a carbon scientist at CarbonPlan.

There are also massive fires that burn between millions of acres in Siberia covering the sky Across and liberating Russia from the east tens of millions of tons spilled, Copernicus reported earlier this month.

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

The risk of fires – defined as moderate or high severity fires in an area – could be severe each year – could quadruple in the U.S. by 2090, even in scenarios where emissions will drop significantly in the coming decades. final examination Conducted by researchers at Utah and CarbonPlan University. With uncontrolled discharges, the U.S. fire risk could be 14 times higher by the end of the century.

Fire emissions “are already bad and will get worse,” says one of the lead authors of the Chegwidden study.

“Very worrying”

Over the longer term, the growth spills and climate impacts of forest fire growth will depend on how forests grow back and carbon sequestration. This depends on the dominant trees, the severity of the fires, and the change in local climatic conditions since the forest was uprooted.

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

It indicated where and when coniferous forests began to return, where they did not, and where opportunistic invasive species such as weeds took over the landscape.

In one 2018 study In Ecology Letters, he and his colleagues concluded that the trees burned in the Rocky Mountains had far more problems growing in this century, as the region was hotter and drier than at the end of the last. Dry coniferous forests that land on the edge of survival conditions become much easier to turn into grass and shrubs, as they generally absorb and store much less carbon.

That can be healthy at some point, creating ceasefires that reduce future fire damage, says Stevens-Rumann, an assistant professor of forest and field care at Colorado State University. The United States can help compile a bit of a history of aggressively returning fires, which has allowed fuel to accumulate in many forests, increasing the tremendous likelihood of fires.

However, his findings are “very worrying,” he says, adding that there are already large fires and forecasts of increasingly hot and dry conditions in the American West.

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

Fires, droughts, insect infestations and changing climatic conditions will turn major parts of California’s forests into shrubs, according to modeling study published in AGU Advances last week. Tree losses can be particularly severe in dense Douglas firs and coastal redwoods in northern California and at the foot of the Sierra Nevada Mountains.

All in all, the state will lose about 9% of the carbon stored in the earth’s trees and plants on the stage where we will stabilize emissions at the end of this century, and in the future world that will continue to rise by more than 16%. .

Among other impacts, this will clearly complicate the state’s confidence in its land to capture and store its carbon. forestry compensations program and other climate efforts, study notes. California is striving to become carbon neutral by 2045.

Meanwhile, medium- or high-emission scenarios create a “real probability that Yellowstone’s forests will become out-of-forest vegetation in the mid-20th century,” as more and more common and larger fires make it increasingly difficult to grow trees again. , A 2011 study in Proceedings of the National Academy of Sciences was completed.

Global image

The impact of climate change on fires and the effects of fires on climate change is much more difficult globally.

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

But fires can also cause a negative climate opinion. The smoke from the western fires reached the east coast in recent days, although it is devastating to human health. carries aerosols which reflect the heat level into space. At the same time, fires in the boreal forests They could open up a space that is much more reflective than the forests they replaced in Canada, Alaska, and Russia, offsetting the warming effect of the spills.

Many parts of the world are also pushing and pulling in different ways.

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

But it is the entire surface burned by fires around the world really goes down, mainly due to the declines in the tropics of the savannahs and meadows. Among other factors, widespread farms and roads are dividing the landscape by developing in parts of Africa, Asia and South America, acting as a rupture of these fires. Meanwhile, growing livestock are ingesting fuel.

Overall, the global emissions from fires are one-fifth of fossil fuels, however not significantly rising yet. But clearly, forest spills are rising as fires, deforestation and trees enter. They have gone from being less than 5 billion tons in 2001 to more than 10,000 billion in 2019 Nature Climate Change paper in January.

Less fuel

As warming continues in the coming decades, climate change itself will affect it in different ways in different areas. While many regions may be hotter, drier, and prone to fires, some of the world’s cooler places will be more conducive to forest growth, such as high mountains and high parts of the Arctic tundra, Randerson says.

Global warming could also reach a point where it begins to reduce some risks. If Yellowstone, the California Sierra Nevada, and other areas lose much of their forest, as research has suggested, fires could begin to return by the end of the century. This is simply because there will be less or less flammable fuel to burn.

It is difficult to make reliable predictions about forest and fire emissions around the world in the coming decades because there are so many competing variables and unknowns, especially what action humans will decide, says Doug Morton, head of NASA’s Goddard Space biosphere science lab. Flight Center.