MSGID: 1:317/3 6402c96b   
   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
    Wildfires in 2021 emitted a record-breaking amount of carbon dioxide   
    UC Irvine-led study found northern-latitude forest fires to be the   
   highest source    
      
     Date:   
         March 3, 2023   
     Source:   
         University of California - Irvine   
     Summary:   
         Carbon dioxide emissions from wildfires, which have been gradually   
         increasing since 2000, spiked drastically to a record high in 2021,   
         according to an international team of researchers.   
      
      
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   FULL STORY   
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   Carbon dioxide emissions from wildfires, which have been gradually   
   increasing since 2000, spiked drastically to a record high in 2021,   
   according to an international team of researchers led by Earth system   
   scientists at the University of California, Irvine.   
      
      
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   Nearly half a gigaton of carbon (or 1.76 billion tons of CO2) was released   
   from burning boreal forests in North America and Eurasia in 2021, 150   
   percent higher than annual mean CO2 emissions between 2000 and 2020,   
   the scientists reported in a paper in Science.   
      
   "According to our measurements, boreal fires in 2021 shattered previous   
   records," said senior co-author Steven Davis, UCI professor of Earth   
   system science. "These fires are two decades of rapid warming and extreme   
   drought in Northern Canada and Siberia coming to roost, and unfortunately   
   even this new record may not stand for long."  The researchers said that   
   the worsening fires are part of a climate-fire feedback in which carbon   
   dioxide emissions warm the planet, creating conditions that lead to more   
   fires and more emissions.   
      
   "The escalation of wildfires in the boreal region is anticipated to   
   accelerate the release of the large carbon storage in the permafrost   
   soil layer, as well as contribute to the northward expansion of shrubs,"   
   said co-author Yang Chen, a UCI research scientist in Earth system   
   science. "These factors could potentially lead to further warming   
   and create a more favorable climate for the occurrence of wildfires."   
   Davis added, "Boreal fires released nearly twice as much CO2 as global   
   aviation in 2021. If this scale of emissions from unmanaged lands becomes   
   a new normal, stabilizing Earth's climate will be even more challenging   
   than we thought."  Analyzing the amount of carbon dioxide released during   
   wildfires is difficult for Earth system scientists for a variety of   
   reasons. Rugged, smoke-enshrouded terrain hampers satellite observations   
   during a combustion event, and space- based measurements are not at a   
   sufficiently fine resolution to reveal details of CO2 emissions. Models   
   used to simulate fuel load, fuel consumption and fire efficiency work   
   well under ordinary circumstances but are not robust enough to represent   
   extreme wildfires, according to the researchers.   
      
   And there is another roadblock of our own creation. "Earth's atmosphere   
   already contains large amounts of carbon dioxide from human fossil fuel   
   burning, and the existing greenhouse gas is difficult to distinguish   
   from that produced by forest fires," said Chen.   
      
   The team found a way around these hurdles by studying carbon monoxide   
   expelled into the atmosphere during blazes. Combining CO readings from   
   MOPITT -- the Measurements Of Pollution In The Troposphere satellite   
   instrument -- with existing fire emissions and wind speed datasets,   
   the team reconstructed changes in global fire CO2 emissions from   
   2000-2021. Carbon monoxide has a shorter lifespan in the atmosphere than   
   CO2, so if scientists detect an anomalous abundance of CO, that provides   
   evidence of fires.   
      
   The researchers independently confirmed the occurrence of extreme fires   
   in 2021 with data sets provided by NASA's Moderate Resolution Imaging   
   Spectroradiometer aboard the Terra and Aqua satellites.   
      
   "The inversion approach employed in this study is a complementary   
   method to the conventional bottom-up approach, which is based on   
   estimating the burned area, fuel load, and combustion completeness,"   
   Chen said. "Combining these approaches can result in a more comprehensive   
   understanding of wildfire patterns and their impacts."  The researchers   
   said their data analysis revealed links between extensive boreal fires   
   and climate drivers, especially increased annual mean temperatures and   
   short-lived heat waves. They found that higher northern latitudes and   
   areas with larger tree cover fractions were especially vulnerable.   
      
   "Wildfire carbon emissions globally were relatively stable at about 2   
   gigatons per year for the first two decades of the 21st century, but   
   2021 was the year when emissions really took off," David said. "About   
   80 percent of these CO2 emissions will be recovered through vegetation   
   regrowth, but 20 percent are lost to the atmosphere in an almost   
   irreversible way, so humans are going to have to find some way to remove   
   that carbon from the air or substantially cut our own production of   
   atmospheric carbon dioxide."   
       * RELATED_TOPICS   
             o Earth_&_Climate   
                   # Wildfires # Global_Warming # Forest # Climate #   
                   Air_Quality # Natural_Disasters # Environmental_Issues   
                   # Earth_Science   
       * RELATED_TERMS   
             o Climate_change_mitigation o Carbon_dioxide_sink o Forest   
             o Climate_model o Carbon_dioxide o Ocean_acidification o   
             Fossil_fuel o Carbon_monoxide   
      
   ==========================================================================   
   Story Source: Materials provided by   
   University_of_California_-_Irvine. Note: Content may be edited for style   
   and length.   
      
      
   ==========================================================================   
   Journal Reference:   
      1. Bo Zheng, Philippe Ciais, Frederic Chevallier, Hui Yang, Josep G.   
      
         Canadell, Yang Chen, Ivar R. van der Velde, Ilse Aben, Emilio   
         Chuvieco, Steven J. Davis, Merritt Deeter, Chaopeng Hong, Yawen   
         Kong, Haiyan Li, Hui Li, Xin Lin, Kebin He, Qiang Zhang. Record-high   
         CO 2 emissions from boreal fires in 2021. Science, 2023; 379   
         (6635): 912 DOI: 10.1126/ science.ade0805   
   ==========================================================================   
      
   Link to news story:   
   https://www.sciencedaily.com/releases/2023/03/230303105251.htm   
      
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