Something important is happening when even the BBC is compelled to ask, as it did this week, “What happened on global warming?” The British news organization has heretofore insisted that the scientific consensus was cemented long ago that global warming is real and is mainly caused by human use of carbon-based fossil fuels. Put simply, what has happened is global temperatures have dropped every year since 1998, recent peer-reviewed research has uncovered the decisive influence of hot and cold cycles in the oceans on land temperatures, and growing numbers of scientists with unquestioned credentials are stepping forward to question the conventional wisdom.

But reaching a new consensus will be exceedingly difficult because the raw data on which the landmark 1996 United Nations Intergovernmental Panel on Climate Change based its conclusion has been destroyed. The University of East Anglia’s Climate Research Unit acknowledged in August that it discarded data that, in addition to the IPCC report, has been cited by other international studies as the main justification for severe restrictions on carbon emissions worldwide. This development raises more troubling doubts about global warming just as scientists and policymakers are expected to call for harsh new limits on energy use in its name when they meet in December in Copenhagen, Denmark.