The climate research community believes that published findings on global warming will have an equal probability of raising or lowering forecasts of climate change and its impact. This is a testable hypothesis based upon the recent literature and the assumption that extant forecasts are themselves unbiased. A survey of Science and Nature demonstrates that the likelihood that recent literature is not biased in a positive or negative direction is less than one in 5.2 × 10^-16. This has considerable implications for the popular perception of global warming science, for the nature of "compendia" of climate change research, such as the reports of the United Nations' Intergovernmental Panel on Climate change, and for the political process that uses those compendia as the basis for policy.