Transcript Designing a Strategy to Save Arctic Ice from Global Warming With

Geoengineering: Designing a Strategy to
Save Arctic Ice from Global Warming with
Stratospheric Sulfate Aerosols
Allison Marquardt
Department of Environmental Sciences, Rutgers University, New Brunswick, NJ
As seen in figure 3, the spring injection
scenarios do not indicate that the
monsoon has failed in India or Africa,
although there are fluxes in precipitation
over the oceans.
Introduction
With global warming becoming more of a
concern to society, as well as entire
ecosystems, it is important to address
proposed methods to alleviate its negative
impacts. The Arctic is seeing more changes
than anywhere else in the world, and
endangered species, such as polar bears,
may become extinct as they continue to lose
their habitat. Geoengineering is one
possible way to cool that climate, and in this
situation is characterized by injecting sulfur
aerosols into the stratosphere. The goal of
this experiment is to see if it is possible to
modify the climate using geoengineering to
save Arctic ice without jeopardizing other
locations throughout the world including the
monsoon regions of India and Africa.
Experimental Design
In order to complete this experiment many
model runs were required. There are two
control runs, one that maintains constant
conditions from the year 1999, and the other
with constant conditions from the year 2007.
In addition to the control runs, the
geoengineering runs were also compared to
the A1B scenario as indicated by the IPCC
(2007). There were three different
geoengineering runs, each with three
ensemble members. Each run injects the
sulfur aerosol at a rate of 3 MT per year,
however one continuously injects the sulfur
throughout the entire, the second during the
months of April, May, and June, and the last
injects the same quantity as the second run,
however only during the month of April.
Since changes were made to the model in
between the initiation of the year-round and
spring geoengineering , a “pseudo A1B” run
was created to make all of the output
comparable.
Figure 1: 3MT per year injection compared to the A1B ensemble
averaged over years 10 to 19. (a) Surface Air Temperature flux (b)
Precipitation flux (Robock et al. 2007)
Not only does a 3MT injection decrease
the surface air temperature, but it also
contributes to replenishing the Arctic Sea
ice, including during the month of
September when the peak ice melt usually
occurs. With a 3MT injection per year, the
ocean ice thickness will increase by 8%,
while the snow and ice coverage within
each grid will increase by 6% in the
Greenland and Norwegian Seas on an
annual average when compared to the
A1B scenario. In addition, the ice over
northern Europe and Asia will even
increase by over 25 kg/m2. As shown in
figure 2, the two spring scenarios showed
a very similar increase in the sea ice in the
Arctic.
Conclusions
The spring geoengineering scenarios
proved to be just as effective as the
year-round scenario. If geoengineering
were to be exercised to replenish Arctic
ice, it would be more efficient. Scientists
have the knowledge to modify the
Earth’s climate but there are many
political boundaries that most be crossed
in order to do so. In addition,
geoengineering could only be used as a
temporary solution, and these scenarios
are not capable of reversing all of the
negative impacts of global warming,
spanning the entire Earth.
Acknowledgements
I would like to thank Ben Kravitz and Dr. Alan
Robock for their support and guidance in
completing this research as well as NSF Grant
ATM-0730452.
References
Results
Figure 1a shows that geoengineering is
doing what is expected during the yearround scenario. The sulfur is only affected
the temperature above 60 degrees north is
latitude, with the majority of the Arctic
seeing a decrease in temperature of at least
0.6 degrees Celsius on an annual average.
Figure 1b confirms the preliminary
experiments that the Indian and African
monsoon will fail, by the large decrease in
precipitation, which turns out to be
statistically significant when divided by the
standard deviation.
Figure 3: Precipitation flux compared to the A1B ensemble averaged
over years 10-19. (a) 0.75MT/Spring (b) 0.75MT/April
IPCC, 2007: Summary for Policymakers. In:
Climate Change 2007: Impacts, Adaption and
Vulnerability. Contribution of Working Group II
to the Fourth Assessment Report of the
Intergovernmental Panel on Climate Change,
M.L. Parry, O.F. Canziani, J.P. Palutikof, P.J.
van der Linden and C.E. Hanson, Eds.,
Cambridge University Press, Cambridge, UK,
7-22.
Figure 2: Total earth ice flux compared to the A1B ensemble averaged
over years 10-19. (a) 3MT/year (b) 0.75MT/April
Robock, Alan, Luke Oman, and Georgiy L.
Stenchikov, 2008: Regional climate responses
to geoengineering with tropical and Arctic SO2
injections, Journal of Geophysical Research,
113, D16101, doi:10.1029/2008JD010050.