* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download What is a global climate model? - Climate Change Information
Myron Ebell wikipedia , lookup
Mitigation of global warming in Australia wikipedia , lookup
Climatic Research Unit email controversy wikipedia , lookup
Soon and Baliunas controversy wikipedia , lookup
Heaven and Earth (book) wikipedia , lookup
Michael E. Mann wikipedia , lookup
Global warming hiatus wikipedia , lookup
Effects of global warming on human health wikipedia , lookup
2009 United Nations Climate Change Conference wikipedia , lookup
ExxonMobil climate change controversy wikipedia , lookup
German Climate Action Plan 2050 wikipedia , lookup
Instrumental temperature record wikipedia , lookup
Numerical weather prediction wikipedia , lookup
Global warming controversy wikipedia , lookup
Climate resilience wikipedia , lookup
Climate change denial wikipedia , lookup
Fred Singer wikipedia , lookup
Climatic Research Unit documents wikipedia , lookup
Climate change adaptation wikipedia , lookup
Economics of global warming wikipedia , lookup
Climate change in Tuvalu wikipedia , lookup
United Nations Framework Convention on Climate Change wikipedia , lookup
Atmospheric model wikipedia , lookup
Effects of global warming wikipedia , lookup
Global warming wikipedia , lookup
Politics of global warming wikipedia , lookup
Climate change and agriculture wikipedia , lookup
Carbon Pollution Reduction Scheme wikipedia , lookup
Climate engineering wikipedia , lookup
Media coverage of global warming wikipedia , lookup
Citizens' Climate Lobby wikipedia , lookup
Climate sensitivity wikipedia , lookup
Climate governance wikipedia , lookup
Climate change feedback wikipedia , lookup
Climate change in the United States wikipedia , lookup
Effects of global warming on humans wikipedia , lookup
Scientific opinion on climate change wikipedia , lookup
Attribution of recent climate change wikipedia , lookup
Climate change and poverty wikipedia , lookup
Public opinion on global warming wikipedia , lookup
Solar radiation management wikipedia , lookup
Climate change, industry and society wikipedia , lookup
Surveys of scientists' views on climate change wikipedia , lookup
1 What is a global climate model? Key Points Global climate models (GCMs) are mathematical formulations of the processes that comprise the climate system. Climate models can be used to make projections about future climate and the knowledge gained can contribute to policy decisions regarding climate change. An advantage of GCMs is their ability to perform multiple simulation experiments using different greenhouse gas emissions scenarios. A disadvantage of GCMs is their inability to resolve features smaller than about 50 miles by 50 miles. However, as computing power continues to increase, models are being constantly improved. How Climate Models Work tation of water, and transport of heat by ocean currents. The model calculations are made for individual gridboxes on the order of 125 – 300 miles (200 – 500 km) in the horizontal and vertical dimensions. The equations of the model are solved for the atmosphere, land surface, and oceans in each gridbox over the entire globe using a series of timesteps (Figure 1). Projections Made by Global Climate Models GCMs are used to simulate the climate system’s future responses to emissions of greenhouse gases and sulfate aerosols, as well as other human-induced activities that affect the climate system. Projections made by GCMs are reflections of the current state of knowledge of the processes in the climate system, but they still contain uncertainties. Figure 2 shows projected changes in temperature and precipitation in the 2050s using two global climate models, one developed by the United Kingdom Hadley Centre and the other by the Canadian Centre for Climate Modeling and Analysis. Computer climate models are the key tool for simulating possible future climates. Though there are many types of models, from simple to complex, threedimensional global atmosphere and ocean models hold the most potential for making accurate climate projections. These complex and computer-intensive global climate models have been developed to study global climate processes Advantages and and to create projecDisadvantages of tions of possible Climate Models future climates. The An advantage of knowledge gained climate models can contribute to is their ability to policy decisions Figure 1. Schematic illustration of GCM structure at a single gridbox.Source: Hansen, J., G. Russell, D. perform multiple regarding climate Rind, et al. “Efficient three-dimensional models for global climate studies: Models I and II. “ Monthly simulation experichange and facilitate Weather Review 111 (4): 609, 662, 1983 ments using differpreparations for fuent greenhouse gas ture climate changes. emissions scenarios. GCMs are mathematical formulations of the processes that By performing multiple experiments, with multiple climate comprise the climate system, including radiation, energy models based on multiple greenhouse gas scenarios, the transfer by winds, cloud formation, evaporation and precipiThis project is funded by the National Oceanic and Atmospheric Administration (NOAA) under grant #NA16GP2576. For more information about CCIR visit http://ccir.ciesin.columbia.edu/nyc CIESIN User Services: 1 (845) 365-8988 8922 http://www.ciesin.columbia.edu/ Copyright© 2004-2005. The Trustees of Columbia University in the City of New York. What is a global climate model? range of possible climate outcomes, as well as the probability of specific outcomes, can be better understood. A disadvantage of climate models is that, although computer power continues to increase rapidly, global models currently do not resolve features smaller than about 50 miles x 50 miles. This makes it impossible to resolve smaller-scale climate features. The models also simplify or parametrize complex and often non-linear processes, such as the radiation effects of high- and low-level clouds or hydrological processes on the land. References Flato, G.M., G.J. Boer, W.G. Lee, N.A. McFarlane, D. Ramsden, M.C. Reader, and A.J. Weaver. 1997. The Canadian Centre for Climate 2 Modeling and Analysis global coupled model and its climate. The Canadian Centre for Climate Modeling and Analysis. Atmospheric Environment Service. University of Victoria, BC. Intergovernmental Panel on Climate Change (IPCC), 2001. “Working Group I Third Assessment Report.” Cambridge University Press.Cambridge, UK. 881 pp. Johns, T.E., R.E. Carnell, J.F. Crossley, J.M. Gregory, J.F.B. Mitchell, C.A. Senior, S.F.B. Tett, and R.A. Wood. 1997. “The second Hadley Centre coupled ocean-atmosphere GCM: Model description, spinup, and validation.” Climate Dynamics 13:103-134. Cynthia Rosenzweig, Goddard Institute for Space Studies (http://www.giss.nasa.gov/) William Solecki, Hunter College, City University of New York (http://www.hunter.cuny.edu/) Figure 2.Projected changes in temperature and precipitation for the 2050s. Left: United Kingdom Hadley Center. Right: Canadian Center for Climate Modeling and Analysis. Source:Rosenzweig and Solecki, Climate Change and a Global City, 2001. This project is funded by the National Oceanic and Atmospheric Administration (NOAA) under grant #NA16GP2576. For more information about CCIR visit http://ccir.ciesin.columbia.edu/nyc CIESIN User Services: 1 (845) 365-8988 8922 http://www.ciesin.columbia.edu/ Copyright© 2004-2005. The Trustees of Columbia University in the City of New York.