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Titel |
Possible future changes in extreme events over Northern Eurasia |
VerfasserIn |
Erwan Monier, Andrei Sokolov, Jeffery Scott |
Konferenz |
EGU General Assembly 2013
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Medientyp |
Artikel
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Sprache |
Englisch
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Digitales Dokument |
PDF |
Erschienen |
In: GRA - Volume 15 (2013) |
Datensatznummer |
250077889
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Zusammenfassung |
In this study, we investigate possible future climate change over Northern Eurasia and its
impact on extreme events. Northern Eurasia is a major player in the global carbon budget
because of boreal forests and peatlands. Circumpolar boreal forests alone contain more than
five times the amount of carbon of temperate forests and almost double the amount of carbon
of the world’s tropical forests. Furthermore, severe permafrost degradation associated with
climate change could result in peatlands releasing large amounts of carbon dioxide and
methane. Meanwhile, changes in the frequency and magnitude of extreme events, such as
extreme precipitation, heat waves or frost days are likely to have substantial impacts on
Northern Eurasia ecosystems. For this reason, it is very important to quantify the
possible climate change over Northern Eurasia under different emissions scenarios,
while accounting for the uncertainty in the climate response and changes in extreme
events.
For several decades, the Massachusetts Institute of Technology (MIT) Joint Program on the
Science and Policy of Global Change has been investigating uncertainty in climate change
using the MIT Integrated Global System Model (IGSM) framework, an integrated assessment
model that couples an earth system model of intermediate complexity (with a 2D zonal-mean
atmosphere) to a human activity model. In this study, regional change is investigated using
the MIT IGSM-CAM framework that links the IGSM to the National Center for Atmospheric
Research (NCAR) Community Atmosphere Model (CAM). New modules were developed
and implemented in CAM to allow climate parameters to be changed to match those of the
IGSM.
The simulations presented in this paper were carried out for two emission scenarios, a
“business as usual” scenario and a 660 ppm of CO2-equivalent stabilization, which are
similar to, respectively, the Representative Concentration Pathways RCP8.5 and RCP4.5
scenarios. Values of climate sensitivity and net aerosol forcing used in the simulations within
the IGSM-CAM framework provide a good approximation for the median, and the lower and
upper bound of 90% probability distribution of 21st century climate change. Five member
ensembles were carried out for each choice of parameters using different initial conditions.
With these simulations, we investigate the role of emissions scenarios (climate
policies), the global climate response (climate sensitivity) and natural variability (initial
conditions) on the uncertainty in future climate changes over Northern Eurasia. A
particular emphasis is made on future changes in extreme events, including frost
days, extreme summer temperature and extreme summer and winter precipitation. |
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