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| Titel |
Does climate uncertainty mean we will need large-scale air capture? |
| VerfasserIn |
Niel Bowerman, David Frame, Myles Allen |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250043283
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| Zusammenfassung |
| The uncertainty in the climate response to carbon emissions implies a strong likelihood
that a temperature target such as limiting global warming to 2Ë C or even 4Ë C
may be exceeded almost irrespective of emission policies adopted today. Due to
the thermal inertia in the climate system, however, a period of negative emissions
might stabilise temperatures if the response turns out to be higher than expected. We
explore the likelihood of such a scenario and the magnitude of negative emissions in
light of the current understanding of the climate response to cumulative carbon
emissions.
We consider an adaptive learning scenario in which society’s understanding of the climate
system improves over time. In this scenario, society responds to improvements in
understanding by adapting its emissions pathways in order to reach a static temperature
target. The magnitude by which temperatures rise faster or slower than previously considered
is used to determine how much society perturbs its emission scenarios in the positive or
negative direction. We consider initial unperturbed emission scenarios that will result in a
best-guess carbon-dioxide-induced global warming of 2Ë C, noting that this also
allows a high-likelihood of greater, or lesser, warming due to the uncertainty in the
temperature response. Two strategies are explored: in one case society perturbs
emissions if it finds itself living in a world that might not have 2Ë C of warming, and in
another society perturbs emissions only if it finds itself living in a world where
temperatures might rise above 4Ë C. We assess the relative likelihood of different levels of
negative emissions during the 21st Century for each of these cases. We find significant
likelihood that emissions must become negative in order to avoid more than 2Ë C of
warming.
These findings suggest that, in the absence of albedo modification, we cannot rule out
the need to use large-scale air capture to avoid 2Ë C of warming in the future. If
such large-scale carbon capture turns out to be technologically and economically
unfeasible, then we cannot rule out temperatures rising by more than 2Ë C in the future,
even on an initial emissions pathway with a best-guess warming of only 2Ë C. |
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