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| Titel |
Modelled impacts of solar geoengineering on the atmosphere: Do feedbacks between composition and meteorology matter? |
| VerfasserIn |
Peer Nowack, Peter Braesicke, Luke Abraham, John Pyle |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250089475
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| Publikation (Nr.) |
 EGU/EGU2014-3681.pdf |
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| Zusammenfassung |
| We use the recently developed atmosphere-ocean chemistry-climate model AO-UMUKCA to
investigate the impact of an extreme Solar Geoengineering (SG) perturbation that
counteracts a strong greenhouse warming. Our focus is on atmospheric composition and
circulation changes and the corresponding feedback effects in the Earth system.
Starting from pre-industrial conditions, the model is used to simulate (a) a strong
climate change scenario by quadrupling atmospheric carbon dioxide (4xCO2) and
(b) an idealized SG experiment in which the greenhouse gas induced warming in
the global mean surface temperature is offset by reducing the solar constant. Two
groups of experiments have been performed, one with and one without interactive
chemistry.
We find large changes in key species (e.g. ozone, methane, etc.) under the interactively forced
scenarios relative to pre-industrial conditions. This expected chemistry feedback was not
accounted for in earlier analogous geoengineering studies. Our experiments demonstrate the
potential importance of such stratospheric composition changes for the near-surface
temperature signal. We are the first to quantify the differences between interactive and
non-interactive simulations. For instance, the interactive run produces about 20% less surface
warming under 4xCO2. In the SG experiment 1.1 W/m2 more dimming was needed in the
non-interactive case. Finally, we show how this affects other important climate patterns
such as the El Nino Southern Oscillation and characterise the drivers of change. |
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