Gao Xiang

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Gao
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Xiang
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Description and evaluation of the MIT Earth System Model (MESM)

2018-08-15 , Sokolov, Andrei P. , Kicklighter, David W. , Schlosser, C. Adam , Wang, Chien , Monier, Erwan , Brown-Steiner, Benjamin , Prinn, Ronald G. , Forest, Chris E. , Gao, Xiang , Libardoni, Alex , Eastham, Sebastian

The Massachusetts Institute of Technology Integrated Global System Model (IGSM) is designed for analyzing the global environmental changes that may result from anthropogenic causes, quantifying the uncertainties associated with the projected changes, and assessing the costs and environmental effectiveness of proposed policies to mitigate climate risk. The IGSM consists of the Massachusetts Institute of Technology Earth System Model (MESM) of intermediate complexity and the Economic Projections and Policy Analysis model. This paper documents the current version of the MESM, which includes a two‐dimensional (zonally averaged) atmospheric model with interactive chemistry coupled to the zonally averaged version of Global Land System model and an anomaly‐diffusing ocean model.

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Permafrost degradation and methane : low risk of biogeochemical climate-warming feedback

2013-07-10 , Gao, Xiang , Schlosser, C. Adam , Sokolov, Andrei P. , Walter Anthony, Katey M. , Zhuang, Qianlai , Kicklighter, David W.

Climate change and permafrost thaw have been suggested to increase high latitude methane emissions that could potentially represent a strong feedback to the climate system. Using an integrated earth-system model framework, we examine the degradation of near-surface permafrost, temporal dynamics of inundation (lakes and wetlands) induced by hydro-climatic change, subsequent methane emission, and potential climate feedback. We find that increases in atmospheric CH4 and its radiative forcing, which result from the thawed, inundated emission sources, are small, particularly when weighed against human emissions. The additional warming, across the range of climate policy and uncertainties in the climate-system response, would be no greater than 0.1 ° C by 2100. Further, for this temperature feedback to be doubled (to approximately 0.2 ° C) by 2100, at least a 25-fold increase in the methane emission that results from the estimated permafrost degradation would be required. Overall, this biogeochemical global climate-warming feedback is relatively small whether or not humans choose to constrain global emissions.

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Toward a consistent modeling framework to assess multi-sectoral climate impacts

2018-02-13 , Monier, Erwan , Paltsev, Sergey , Sokolov, Andrei P. , Chen, Y.-H. Henry , Gao, Xiang , Ejaz, Qudsia , Couzo, Evan , Schlosser, C. Adam , Dutkiewicz, Stephanie , Fant, Charles , Scott, Jeffery , Kicklighter, David W. , Morris, Jennifer , Jacoby, Henry D. , Prinn, Ronald G. , Haigh, Martin

Efforts to estimate the physical and economic impacts of future climate change face substantial challenges. To enrich the currently popular approaches to impact analysis—which involve evaluation of a damage function or multi-model comparisons based on a limited number of standardized scenarios—we propose integrating a geospatially resolved physical representation of impacts into a coupled human-Earth system modeling framework. Large internationally coordinated exercises cannot easily respond to new policy targets and the implementation of standard scenarios across models, institutions and research communities can yield inconsistent estimates. Here, we argue for a shift toward the use of a self-consistent integrated modeling framework to assess climate impacts, and discuss ways the integrated assessment modeling community can move in this direction. We then demonstrate the capabilities of such a modeling framework by conducting a multi-sectoral assessment of climate impacts under a range of consistent and integrated economic and climate scenarios that are responsive to new policies and business expectations.