Geoengineering as a design problem

• Published in: Earth System Dynamics
• Main Authors: B. Kravitz, D. G. MacMartin, H. Wang, P. J. Rasch
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2016
• Subjects: Science; Q; Geology; QE1-996.5; Dynamic and structural geology; QE500-639.5; Arctic
• Online Access: https://doi.org/10.5194/esd-7-469-2016; https://doaj.org/article/ad942b5329464f6684bd63cf97e59938

Understanding the climate impacts of solar geoengineering is essential for evaluating its benefits and risks. Most previous simulations have prescribed a particular strategy and evaluated its modeled effects. Here we turn this approach around by first choosing example climate objectives and then designing a strategy to meet those objectives in climate models. There are four essential criteria for designing a strategy: (i) an explicit specification of the objectives, (ii) defining what climate forcing agents to modify so the objectives are met, (iii) a method for managing uncertainties, and (iv) independent verification of the strategy in an evaluation model. We demonstrate this design perspective through two multi-objective examples. First, changes in Arctic temperature and the position of tropical precipitation due to CO 2 increases are offset by adjusting high-latitude insolation in each hemisphere independently. Second, three different latitude-dependent patterns of insolation are modified to offset CO 2 -induced changes in global mean temperature, interhemispheric temperature asymmetry, and the Equator-to-pole temperature gradient. In both examples, the "design" and "evaluation" models are state-of-the-art fully coupled atmosphere–ocean general circulation models.