Wildfires in these forests could release a stunning amount of planet-warming gases, 科学家说

Wildfires in the vast and pristine forests of Canada, Europe and the far Northern US could release an enormous amount of planet-warming emissions between now and 2050, putting the world’s climate goals in peril, scientists reported Wednesday.

A study published in the journal Science Advances found that wildfires in the North American boreal forests — already increasing due to global warming — could spew nearly 12 gigatons of carbon emissions into the atmosphere over the next three decades. That’s equivalent to the annual emissions of 2.6 billion fossil fuel-powered cars.
Carly Phillips, lead author of the study and a fellow with the Union of Concerned ScientistsWestern States Climate Team, said it’s acascade of consequencesbrought on by the climate crisis.
    The biggest takeaway is that these fires in boreal areas are releasing huge quantities of carbon to the atmosphere, and as a result are really jeopardizing our ability to meet certain climate targets.Phillips told CNN. “A lot is at stake.
      It almost goes without saying that there are real effects for people on the ground who are living through these wildfires,” 她补充说. “There are transportation impacts, tourism impacts, economic impacts and so on from these fires that can be really devastating on local communities.
        The boreal forest, 也称为 “taiga,” is the world’s largest and most intact biome, forming a sprawling, dense ring of woodlands situated below the Arctic circle and spanning vast tracts of the Northern Hemisphere in North America, Europe and Russia. This ecosystem — with trees like spruce, pine, and fir — make up about one-third of all forests on the planet.
        Unseasonably hot temperatures combined with dry conditions have transformed the boreal forest in much of Alberta into a tinder box on May 4, 2016.

        在过去, researchers have called the boreal foreststhe carbon the world forgot,” because it stores roughly 30 至 40% of all land-based carbon in the world, mostly tucked in the soil. The northern hemisphere’s cold temperatures prevent dead biomass from breaking down, storing carbon for thousands of years deep in the permafrost.
          But as climate change and industrial activities advanced deeper into the vital ecosystem, degrading the land and spewing more planet-warming gases that fuel devastating wildfires, many climate researchers fear that the boreal could reach a tipping point, beyond which they shift from absorbing carbon dioxide from the atmosphere to emitting it.
          The boreal forests are warming twice as fast as other parts of the world. 这些年来, researchers say it has become a vicious climate change feedback loop: the emissions from wildfires contributes to increasing global temperatures, which in turn fuel wildfires.
          One of the challenging and interesting things about wildfires right now is that they are both driven by climate change and drivers of climate change,” 菲利普斯说.
          The burned area in the Alaskan boreal forests could increase as much as 169% 通过 2050, the study notes, while burned area in the Canadian boreal could expand by up to 150%.
          Philips says their findings are likely conservative estimates, considering they did not assess rapid permafrost thaw and other harmful greenhouse gases emitted from the fires including methane and nitrous oxide, which lead to higher atmospheric temperatures.
          We know that the implications of wildfires in these areas is that there can be feedbacks to permafrost thaw and as a result, the exposure and release of that anciently stored carbon,” 她说. “Secondly, we are only accounting for the direct emissions from the fire and then regrowth but we aren’t accounting for the decomposition that can occur after the fire.
          一个 recent UN report, which found that the number of extreme wildfire events globally will increase by up to 30% 通过 2050, said that it’s time for the planet to adapt andlearn to live with firethrough better fire management practices to prevent more lives and economies from being put in harm’s way.
            仍然, Phillips and her colleagues found the North American boreal forests disproportionately receive little funding for fire management efforts. 根据报告, Alaska accounts for about 20% of the country’s burned land area as well as half of its fire emissions annually, yet the state only receives roughly an average of 4% of federal fire management funding.
            We’re now seeing the smoke from these fires move across the world, and so that really underscores that this is a global issue, while some of the most detrimental impacts are localized,” 菲利普斯说. “The effects of these fires is of global significance. And this is an opportunity for us to address these heat-trapping emissions that are coming out of these wildfires.

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