Aggressive Aerosol Mitigation Policies Reduce Chances of Keeping Global Warming to Below 2C
Abstract Aerosol increases over the 20th century delayed the rate at which Earth warmed as a result of increases in greenhouse gases (GHGs). Aggressive aerosol mitigation policies arrested aerosol radiative forcing from ∼1980 to ∼2010. Recent evidence supports decreases in forcing magnitude since th...
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| Format: | Article |
| Language: | English |
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Wiley
2024-07-01
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| Series: | Earth's Future |
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| Online Access: | https://doi.org/10.1029/2023EF004233 |
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| author | R. Wood M. A. Vogt I. L. McCoy |
| author_facet | R. Wood M. A. Vogt I. L. McCoy |
| author_sort | R. Wood |
| collection | DOAJ |
| description | Abstract Aerosol increases over the 20th century delayed the rate at which Earth warmed as a result of increases in greenhouse gases (GHGs). Aggressive aerosol mitigation policies arrested aerosol radiative forcing from ∼1980 to ∼2010. Recent evidence supports decreases in forcing magnitude since then. Using the approximate partial radiative perturbation (APRP) method, future shortwave aerosol effective radiative forcing changes are isolated from other shortwave changes in an 18‐member ensemble of ScenarioMIP projections from phase 6 of the Coupled Model Intercomparison Project (CMIP6). APRP‐derived near‐term (2020–2050) aerosol forcing trends are correlated with published model emulation values but are 30%–50% weaker. Differences are likely explained by location shifts of aerosol‐impacting emissions and their resultant influences on susceptible clouds. Despite weaker changes, implementation of aggressive aerosol cleanup policies will have a major impact on global warming rates over 2020–2050. APRP‐derived aerosol radiative forcings are used together with a forcing and impulse response model to estimate global temperature trends. Strong mitigation of GHGs, as in SSP1‐2.6, likely prevents warming exceeding 2C since preindustrial but the strong aerosol cleanup in this scenario increases the probability of exceeding 2C by 2050 from near zero without aerosol changes to 6% with cleanup. When the same aerosol forcing is applied to a more likely GHG forcing scenario (i.e., SSP2‐4.5), aggressive aerosol cleanup more than doubles the probability of reaching 2C by 2050 from 30% to 80%. It is thus critical to quantify and simulate the impacts of changes in aerosol radiative forcing over the next few decades. |
| format | Article |
| id | doaj-art-7264c1bfdd2049f2b0e1a01eb458cdc9 |
| institution | Kabale University |
| issn | 2328-4277 |
| language | English |
| publishDate | 2024-07-01 |
| publisher | Wiley |
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| series | Earth's Future |
| spelling | doaj-art-7264c1bfdd2049f2b0e1a01eb458cdc92025-01-29T07:58:52ZengWileyEarth's Future2328-42772024-07-01127n/an/a10.1029/2023EF004233Aggressive Aerosol Mitigation Policies Reduce Chances of Keeping Global Warming to Below 2CR. Wood0M. A. Vogt1I. L. McCoy2Department of Atmospheric Sciences University of Washington Seattle WA USADepartment of Atmospheric Sciences University of Washington Seattle WA USACooperative Institute for Research in Environmental Sciences University of Colorado Boulder CO USAAbstract Aerosol increases over the 20th century delayed the rate at which Earth warmed as a result of increases in greenhouse gases (GHGs). Aggressive aerosol mitigation policies arrested aerosol radiative forcing from ∼1980 to ∼2010. Recent evidence supports decreases in forcing magnitude since then. Using the approximate partial radiative perturbation (APRP) method, future shortwave aerosol effective radiative forcing changes are isolated from other shortwave changes in an 18‐member ensemble of ScenarioMIP projections from phase 6 of the Coupled Model Intercomparison Project (CMIP6). APRP‐derived near‐term (2020–2050) aerosol forcing trends are correlated with published model emulation values but are 30%–50% weaker. Differences are likely explained by location shifts of aerosol‐impacting emissions and their resultant influences on susceptible clouds. Despite weaker changes, implementation of aggressive aerosol cleanup policies will have a major impact on global warming rates over 2020–2050. APRP‐derived aerosol radiative forcings are used together with a forcing and impulse response model to estimate global temperature trends. Strong mitigation of GHGs, as in SSP1‐2.6, likely prevents warming exceeding 2C since preindustrial but the strong aerosol cleanup in this scenario increases the probability of exceeding 2C by 2050 from near zero without aerosol changes to 6% with cleanup. When the same aerosol forcing is applied to a more likely GHG forcing scenario (i.e., SSP2‐4.5), aggressive aerosol cleanup more than doubles the probability of reaching 2C by 2050 from 30% to 80%. It is thus critical to quantify and simulate the impacts of changes in aerosol radiative forcing over the next few decades.https://doi.org/10.1029/2023EF004233aerosolglobal warmingcleanupcloudsemissionsclimate |
| spellingShingle | R. Wood M. A. Vogt I. L. McCoy Aggressive Aerosol Mitigation Policies Reduce Chances of Keeping Global Warming to Below 2C Earth's Future aerosol global warming cleanup clouds emissions climate |
| title | Aggressive Aerosol Mitigation Policies Reduce Chances of Keeping Global Warming to Below 2C |
| title_full | Aggressive Aerosol Mitigation Policies Reduce Chances of Keeping Global Warming to Below 2C |
| title_fullStr | Aggressive Aerosol Mitigation Policies Reduce Chances of Keeping Global Warming to Below 2C |
| title_full_unstemmed | Aggressive Aerosol Mitigation Policies Reduce Chances of Keeping Global Warming to Below 2C |
| title_short | Aggressive Aerosol Mitigation Policies Reduce Chances of Keeping Global Warming to Below 2C |
| title_sort | aggressive aerosol mitigation policies reduce chances of keeping global warming to below 2c |
| topic | aerosol global warming cleanup clouds emissions climate |
| url | https://doi.org/10.1029/2023EF004233 |
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