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| Titel |
Effects of aerosol emission pathways on future warming and human health |
| VerfasserIn |
Antti-Ilari Partanen, Damon Matthews |
| 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 |
250129464
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| Publikation (Nr.) |
 EGU/EGU2016-9584.pdf |
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| Zusammenfassung |
| The peak global temperature is largely determined by cumulative emissions of long-lived
greenhouse gases. However, anthropogenic emissions include also so-called short-lived
climate forcers (SLCFs), which include aerosol particles and methane. Previous studies with
simple models indicate that the timing of SLCF emission reductions has only a
small effect on the rate of global warming and even less of an effect on global peak
temperatures. However, these simple model analyses do not capture the spatial
dynamics of aerosol-climate interactions, nor do they consider the additional effects of
aerosol emissions on human health. There is therefore merit in assessing how the
timing of aerosol emission reductions affects global temperature and premature
mortality caused by elevated aerosol concentrations, using more comprehensive climate
models.
Here, we used an aerosol-climate model ECHAM-HAMMOZ to simulate the direct and
indirect radiative forcing resulting from aerosol emissions. We simulated Representative
Concentration Pathway (RCP) scenarios, and we also designed idealized low and high aerosol
emission pathways based on RCP4.5 scenario (LOW and HIGH, respectively). From these
simulations, we calculated the Effective Radiative Forcing (ERF) from aerosol emissions
between 1850 and 2100, as well as aerosol concentrations used to estimate the
premature mortality caused by particulate pollution. We then use the University of
Victoria Earth System Climate Model to simulate the spatial and temporal pattern of
climate response to these aerosol-forcing scenarios, in combination with prescribed
emissions of both short and long-lived greenhouse gases according to the RCP4.5
scenario.
In the RCP scenarios, global mean ERF declined during the 21st century from −1.3 W
m−2 to −0.4 W m−2 (RCP8.5) and −0.2 W m−2 (RCP2.6). In the sensitivity scenarios, the
forcing at the end of the 21st century was −1.6 W m−2 (HIGH) and practically zero
(LOW).
The difference in global mean temperature at the year 2100 between LOW and HIGH was
about 0.4 ∘C. The effect was even more significant on the global mean warming rate that
reached 0.4 ∘C per decade in LOW and only 0.2 ∘C per decade in HIGH. The global
temperature and warming rate were similar to each other in simulations using the aerosol
emissions from standard RCP scenarios.
Anthropogenic aerosols caused significant premature mortality during the 21st
century. In 2005, they caused 1.5 million deaths annually. The annual death rate
dropped to 0.13 million per year in LOW and was 0.9 million per year in HIGH by
2100. Total premature mortality caused by anthropogenic aerosol particles between
2005 and 2100 was 27 million in LOW, 52-68 million in RCPs, and 113 million in
HIGH.
Our results show that both climate and health effects of aerosols are fairly similar
across RCP scenarios. However, RCPs share assumptions on effective air-quality
policies. Our scenarios LOW and HIGH demonstrate that if strong aerosol policies
are not enforced or even more ambitious cuts in aerosol emissions are made, the
aerosol impacts on climate and health can differ significantly between scenarios. |
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