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Global methyl halide emissions from biomass burning during 2003-2021
Xiaoyi Hu1, Di Chen1, Liting Hu1
1College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, PR China.
Environmental Science and Ecotechnology
|December 23, 2022
Summary
Global emissions of ozone-depleting methyl halides from biomass burning (BB) significantly decreased between 2003-2021, with notable increases in northern high latitudes. Non-BB emissions also showed varied trends, highlighting the need to re-evaluate known sources.
Area of Science:
- Atmospheric Chemistry
- Environmental Science
- Remote Sensing
Background:
- Methyl halides (CH3Cl, CH3Br, CH3I) are significant ozone-depleting substances.
- Biomass burning (BB) is a major, yet poorly quantified, source of atmospheric methyl halides.
- Understanding the temporal and spatial dynamics of BB methyl halide emissions is crucial for atmospheric modeling and policy.
Purpose of the Study:
- To estimate global methyl halide emissions from biomass burning between 2003 and 2021 using satellite data.
- To analyze the temporal trends and latitudinal distribution of these emissions.
- To investigate the drivers influencing methyl halide emissions from different types of biomass burning.
Main Methods:
- Utilized satellite-derived data to quantify global methyl halide emissions from biomass burning for the period 2003-2021.
- Performed statistical analysis to identify significant trends and spatial patterns in emissions.
- Correlated emission data with burned area and emission factors for different land cover types.
Main Results:
- A significant decreasing trend in global methyl halide emissions from BB was observed from 2003 to 2021 (CH3Cl: 302 to 220 Gg yr-1; CH3Br: 16.5 to 11.7 Gg yr-1; CH3I: 8.9 to 6.1 Gg yr-1).
- The northern high-latitude region (60-90° N) was the sole latitude zone exhibiting a significant increase in BB methyl halide emissions.
- Emissions from cropland, grassland, and shrubland fires correlated more with burned area, while forest fire emissions correlated with emission per unit area.
- Non-BB CH3Cl emissions increased (4749 to 4882 Gg yr-1), while non-BB CH3Br emissions decreased (136 to 118 Gg yr-1) between 2003-2020.
Conclusions:
- Global methyl halide emissions from biomass burning have declined, but regional increases, particularly in the Arctic, warrant attention.
- The differing emission drivers for various fire types necessitate tailored mitigation strategies.
- Re-evaluating known methyl halide sources, alongside searching for new ones, is essential for effective atmospheric management.
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