Climate change computer models are limited

Computer models that predict climate change have improved during the past decade, but they still have deficiencies such as predicting precipitation over specific regions, according to a report released recently by a unit of the Energy Department. The U.S. Climate Change Science Program’s report, “Climate Models: An Assessment of Strengths and Limitations,” examined some computer models of the earth’s climate and their ability to simulate current climate change. To assure that future climate projections are used appropriately, it's important to understand what current models are able to simulate effectively, the document said. “This report makes an important contribution in helping to describe and explain the current state of high-end climate modeling for the non-specialist,” said David Bader, with DOE’s Lawrence Livermore National Laboratory and the coordinating lead author for the report. The report described complex mathematical models used to simulate the earth’s climate on powerful supercomputers and assesses the model’s ability to reproduce observed climate features. It also studied the model’s sensitivity to changes in conditions such as atmospheric concentrations of carbon dioxide. Despite progress in modeling over the last 10 years, a number of systematic biases remain, particularly in the simulation of regional precipitation, the report said. On smaller geographic scales, when compared to the current climate, the simulated climate varies substantially from model to model, it added. “No current model is superior to others in all respects, but rather different models have differing strengths and weaknesses,” the report stated. To develop the report, DOE chartered a Federal Advisory Committee comprised of 29 members drawn from academia, the government scientific community, nonprofit and for-profit organizations that drafted and oversaw the review of the report.