Global climate changes as forecast by Goddard Institute for Space Studies three-dimensional model

摘要: We use a three-dimensional climate model, the Goddard Institute for Space Studies (GISS) model II with 8° by 10° horizontal resolution, to simulate global effects of time-dependent variations atmospheric trace gases and aerosols. Horizontal heat transport ocean is fixed at values estimated today's climate, uptake perturbations beneath mixed layer approximated as vertical diffusion. make 100-year control run perform experiments three scenarios composition. These begin in 1958 include measured or changes CO2, CH4, N2O, chlorofluorocarbons (CFCs) stratospheric aerosols period from present. Scenario A assumes continued exponential gas growth, scenario B reduced linear growth gases, C rapid curtailment emissions such that net forcing ceases increase after year 2000. Principal results are follows: (1) Global warming level attained peak current interglacial previous occurs all scenarios; however, there dramatic differences levels future warming, depending on growth. (2) The greenhouse should be clearly identifiable 1990s; within next several years predicted reach maintain least standard deviations above climatology 1950s. (3) Regions where an unambiguous appears earliest low-latitude oceans, China interior areas Asia, near Antarctica north pole; aspects spatial temporal distribution model-dependent, implying possibility discrimination 1990s thus improved predictions, if appropriate observations acquired. (4) temperature sufficiently large have major impacts people other parts biosphere, shown computed frequency extreme events comparison trends. (5) suggest some near-term regional variations, despite which suppresses many possible fluctuations; example, during Hie late 1980s tendency greater than average southeastern central United States relatively cooler conditions less western much Europe. uncertainties predictions involve equilibrium sensitivity forcing, assumptions regarding ocean, omission less-certain forcings.