When warming's 'hockey stick' breaks

When is a story on global warming not worth reporting accurately, or maybe not worth covering at all? Evidently, when it undermines the near universal belief in the popular press that the scientific debate is over: "Humans are causing catastrophic global warming and we have to do something about it." Nowhere is this clearer than in the recent reporting surrounding the global warming "hockey stick." The hockey stick is an image used by the United Nations' Intergovernmental Panel on Climate Change (IPCC) that shows relatively stable temperatures from A.D. 1000 (and in later versions from 0 A.D.) to 1900, and a dramatic temperature increase from 1900 to 2000. The conclusion drawn by authors of the image is that human energy use over the last 100 years has caused a dramatic and unprecedented rise in temperatures across the globe. However, several independent studies called into question the hockey stick's conclusions. A number of climate experts noted that the Earth experienced both a widely recognized Medieval Warm Period from about A.D. 800 to 1400, as well as the Little Ice Age from 1600 to 1850. The hockey stick missed both of these significant climate trends. Other researchers found methodological flaws with the hockey stick, arguing some data sources were misused, several calculations were done incorrectly and some of the data were simply obsolete. Because the hockey stick image has been regularly used to promote and justify proposed climate legislation, Congress asked the National Academy of Sciences (NAS) to examine the hockey stick controversy. Their report, released in early July, confirmed many of the criticisms of the hockey stick. Whereas the authors of the research that produced the hockey stick concluded "the 1990s are likely the warmest decade, and 1998 the warmest year, in at least a millennium," the NAS found little confidence could be placed in those claims. The NAS also found the original researchers used proxy data for past temperature reconstructions that were unreliable, the historic climate reconstruction failed important tests for verifiability and the methods used underestimated the uncertainty in the conclusions reached. However, one would hardly know from news reports that the hockey stick had largely failed to pass scientific muster. Rather, press reports typically highlighted the limited areas where the NAS supported the hockey stick research and downplayed the substantive flaws the NAS confirmed. The best spin the NAS could put on the hockey stick research was that the present temperature was likely warmer than at any time in the last 400 years. Yet, this finding is hardly controversial, since 400 years ago we were in the midst of a little ice age and hardly corroborates the "hockey stick" image of climate history, since it missed the little ice age entirely. On July 20, a second analysis requested by Congress was released at a hearing concerning the validity of the Hockey Stick findings. According to Edward Wegman, his team's research found serious statistical flaws that undermine the main conclusion of the hockey stick study. Mr. Wegman and his colleagues concluded, based on the evidence cited and the methodology used by the hockey stick researchers, the idea that the planet is experiencing unprecedented global warming "cannot be supported." Mr. Wegman and his team also concluded that the close ties between scientists in the small paleoclimatology community prevented true peer review of the hockey stick and related analyses. The mainstream media -- both print and broadcast -- were largely, deafeningly silent on the congressional hearings and its findings. The Earth's climate over the last 2,000 years has been characterized by periods of warmer -- as well as significantly cooler -- temperatures than the present. The "hockey stick" picture of dramatic temperature rise in the last 100 years following 1,900 years of relatively constant temperature, is flawed. Public policy -- especially public policy with such wide-ranging consequences as this -- should be based on science, not spin. Yet in recent months, the mainstream press has largely abdicated its role as a provider of objective, balanced reporting on global warming and has adopted the role of advocate. In doing so, the press has done the public, scientific progress and the journalistic profession a profound disservice. It's time for respected reporters to turn their normally skeptical eye to the claims made by all sides in the important debate concerning global warming. H. Sterling Burnett is a senior fellow with the National Center for Policy Analysis.