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| Titel |
Reversibility of the Earth System under an “overshoot” scenario |
| VerfasserIn |
Marie Doutriaux-Boucher, Mark Ringer, Chris D. Jones, Paul Halloran, Olivier Boucher |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250051531
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| Zusammenfassung |
| Climate scenarios whereby atmospheric concentrations of greenhouse gases exceed a
particular target before decreasing towards the target have been considered by some
authors and are referred to as “overshoot” scenarios. They can result from a continued
growth in CO2 emission followed by a rapid decrease in emissions or even negative
emissions under some aggressive climate policy. Overshoot scenarios are relevant
to a class of geoengineering techniques referred to as CO2 air capture or carbon
dioxide removal (CDR). Given that CDR could only be realistically implemented over
several decades with further inertia coming from the carbon cycle, such a scenario
would cause CO2 atmospheric concentrations to increase before they eventually
decrease.
The aim of this study is to present how various components of the Earth system behave
under an idealised climate change scenario where CO2 atmospheric concentrations are
increased and then decreased. The reversibility of the Earth system component is
investigated using the Met Office Hadley Centre HadGEM2-ES model. We ramp up
the CO2 atmospheric concentration by 1% yr-1 starting from pre-industrial level
(286 ppm) up to a quadrupling (1144Â ppm). Four ramp-down scenarios have been
branched with the CO2 concentration prescribed to decrease at 1% yr-1 starting
from 4xCO2, 3xCO2, 2xCO2 and 1.5xCO2. It is shown that while most parameters
exhibit a high degree of reversibility, there are some variables that respond with a
significant time lag to a decrease in CO2 concentrations, with some hysteresis effect. |
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