Modeling climatic effects of anthropogenic carbon dioxide emissions: unknowns and uncertainties

Climate Research

Sallie Baliunas¹  Willie Soon¹  Eric S. Posmentier¹  Sherwood B. Idso¹  Kirill Ya. Kondratyev¹ 

关键词: Climate change;    Climate model;    Global warming;    Carbon dioxide;   

DOI  :  10.3354/cr018259

来源: Inter-Research Science Publishing

【 摘 要 】

ABSTRACT: A likelihood of disastrous global environmental consequences has been surmised as a result of projected increases in anthropogenic greenhouse gas emissions. These estimates are based on computer climate modeling, a branch of science still in itsinfancy despite recent substantial strides in knowledge. Because the expected anthropogenic climate forcings are relatively small compared to other background and forcing factors (internal and external), the credibility of the modeled global and regionalresponses rests on the validity of the models. We focus on this important question of climate model validation. Specifically, we review common deficiencies in general circulation model (GCM) calculations of atmospheric temperature, surface temperature,precipitation and their spatial and temporal variability. These deficiencies arise from complex problems associated with parameterization of multiply interacting climate components, forcings and feedbacks, involving especially clouds and oceans. We alsoreview examples of expected climatic impacts from anthropogenic CO₂ forcing. Given the host of uncertainties and unknowns in the difficult but important task of climate modeling, the unique attribution of observed current climate change toincreased atmospheric CO₂ concentration, including the relatively well-observed latest 20 yr, is not possible. We further conclude that the incautious use of GCMs to make future climate projections from incomplete or unknown forcing scenariosis antithetical to the intrinsically heuristic value of models. Such uncritical application of climate models has led to the commonly held but erroneous impression that modeling has proven or substantiated the hypothesis that CO₂ added to theair has caused or will cause significant global warming. An assessment of the merits of GCMs and their use in suggesting a discernible human influence on global climate can be found in the joint World Meteorological Organisation and United NationsEnvironmental Programme¹s Intergovernmental Panel on Climate Change (IPCC) reports (1990, 1995 and the upcoming 2001 report). Our review highlights only the enormous scientific difficulties facing the calculation of climatic effects of added atmosphericCO₂ in a GCM. The purpose of such a limited review of the deficiencies of climate model physics and the use of GCMs is to illuminate areas for improvement. Our review does not disprove a significant anthropogenic influence on global climate.

【 授权许可】

Unknown