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| Titel |
Including the biogeochemical impacts of deforestation increases projected warming of climate |
| VerfasserIn |
Catherine Scott, Sarah Monks, Dominick Spracklen, Stephen Arnold, Piers Forster, Alexandru Rap, Kenneth Carslaw, Martyn Chipperfield, Carly Reddington, Christopher Wilson |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250134833
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| Publikation (Nr.) |
 EGU/EGU2016-15602.pdf |
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| Zusammenfassung |
| Forests cover almost one third of the Earth’s land area and their distribution is changing as a
result of human activities. The presence, and removal, of forests affects the climate in many
ways, with the net climate impact of deforestation dependent upon the relative strength of
these effects (Betts, 2000; Bala et al., 2007; Davin and de Noblet-Ducoudré, 2010). In
addition to controlling the surface albedo and exchanging carbon dioxide (CO2) and moisture
with the atmosphere, vegetation emits biogenic volatile organic compounds (BVOCs), which
lead to the formation of biogenic secondary organic aerosol (SOA) and alter the
oxidative capacity of the atmosphere, affecting ozone (O3) and methane (CH4)
concentrations.
In this work, we combine a land-surface model with a chemical transport model, a global
aerosol model, and a radiative transfer model to compare several radiative impacts of
idealised deforestation scenarios in the present day.
We find that the simulated reduction in biogenic SOA production, due to complete
global deforestation, exerts a positive combined aerosol radiative forcing (RF) of
between +308.0 and +362.7 mW m−2; comprised of a direct radiative effect of
between +116.5 and +165.0 mW m−2, and a first aerosol indirect effect of between
+191.5 and +197.7 mW m−2. We find that the reduction in O3 exerts a negative
RF of -150.7 mW m−2 and the reduction in CH4 results in a negative RF of -76.2
mWm−2.
When the impacts on biogenic SOA, O3 and CH4 are combined, global deforestation
exerts an overall positive RF of between +81.1 and +135.9 mW m−2 through changes to
short-lived climate forcers (SLCF). Taking these additional biogeochemical impacts into
account increases the net positive RF of complete global deforestation, due to changes in CO2
and surface albedo, by 7-11%. Overall, our work suggests that deforestation has a stronger
warming impact on climate than previously thought.
References:
Bala, G. et al., 2007. Combined climate and carbon-cycle effects of large-scale
deforestation. PNAS, 104, 6550-6555.
Betts, R. A. 2000. Offset of the potential carbon sink from boreal forestation by decreases
in surface albedo. Nature, 408, 187-190.
Davin, E. L. & De Noblet-Ducoudré, N. 2010. Climatic Impact of Global-Scale
Deforestation: Radiative versus Non-radiative Processes. Journal of Climate, 23,
97-112.
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