Climate Responses to Stratospheric SRM: Results from a Perturbed Physics Ensemble Modeling Experiment
Abstract
While many have argued that the potential future deployment of solar radiation management (SRM) technologies hinges upon the uncertainty around the value of climate sensitivity, modeling studies of the climate’s response to SRM forcings have thus far focused on best-guess modeling frameworks which yield climate sensitivity values close to the Coupled Model Intercomparison Project (CMIP) dataset mean. Thus, most SRM modeling experiments to-date say little about the range of climate responses we may observe if SRM were implemented in high- or low- climate sensitivity worlds. The work presented here aims to see how climate responses to SRM under the physics that produce high climate sensitivity may differ from the responses modeled so far using best-guess model parameters. We present preliminary results from a “perturbed physics” ensemble modeling experiment implemented using climateprediction.net (cpdn). Perturbed physics climate modeling experiments simulate past and future climate scenarios using a wide combination of model parameter combinations with the aim of both simulating past climate with some level of accuracy and also projecting future climates that exhibit a wide range of climate sensitivities. Ensemble members were selected using an algorithm for model selection regional surface temperature data from the cpdn simulation output for model years 1961-2005 (in five year averages) to observational data from the HadCRUT3 (land) and HadSST2 (ocean) datasets at the same spatial and temporal resolution. Stratospheric SRM is simulated in the model by specifying stratospheric optical depth. Several scenarios are tested including several designed to stabilize mean global temperature at different levels, two scenarios designed to rapidly cool the climate starting in 2020 and 2035, respectively, and a scenario which makes small, periodic perturbations (in order to glean information about detectability and the feasibility of large-scale SRM testing schemes). All scenarios use anthropogenic emissions scenario RCP 4.5 and are compared to an RCP 4.5/no-SRM control. We will present global and regional results from this ongoing experiment.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFMGC22A..04R
- Keywords:
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- 1620 GLOBAL CHANGE / Climate dynamics;
- 1626 GLOBAL CHANGE / Global climate models