Evaluation of global climate models’ (gcms’) role in understanding of

Please write a “one page” (about 500 words, or two double-spaced pages) critical evaluation of Global Climate Models’ (GCMs’) role in understanding of Anthropogenic Global Warming (AGW). Are GCMs more or less convincing than historical observations (ice ages, historical temperature changes, proxies), contemporary (i.e., since 1900) measurements, or physical understanding.