In its simplest, cable-television version, this charge, at least against scientists, is outrageous. The assumption that the vast majority in a scientific field is engaged in fraud or corruption is frankly conspiratorial. In this case, the conspiracy would need to encompass the national academies of more than two dozen countries, including the United States.

Other, more measured criticisms ring truer. Some scientists have displayed an artificial certainty on some matters that seems to cross into advocacy. Others assume that the only way to deal with greenhouse gas emissions is a strict, global regulatory regime — an economic and political judgment that has nothing to do with their actual expertise.

But none of these objections relates to the scientific question: Is a 40 percent increase in the atmospheric concentration of carbon dioxide since the Industrial Revolution driving disruptive warming? And further: Can this process be slowed, allowing societies and ecosystems more time to adapt?

Our intuitions are useless here. The only possible answers come from science. And for non-scientists, this requires a modicum of trust in the scientific enterprise. Even adjusting for the possibility of untoward advocacy, it seems clear that higher concentrations of carbon dioxide in the atmosphere have produced a modest amount of warming and are likely to produce more.