It dates back to the mid-20th century
There’s something strange and disturbing about the fact that what Naomi Oreskes says here is in an opinion column rather on than the front page of the news section. It is, from the perspective of public education and policymaking, the single most relevant fact about climate change: the basic consensus about it is longstanding and rock solid. Even more so than most scientists are aware of, it seems.
For instance, did you know this?
One early warning that we "will modify the heat balance of the atmosphere to such an extent that marked changes in climate … could occur" came in 1965 from the Environmental Pollution Board of the President’s Science Advisory Committee. While the Bush administration has been loath to accept this reality, an earlier administration accepted it as a statement of scientific fact. In a special message to Congress in February 1965, President Lyndon B. Johnson noted: "This generation has altered the composition of the atmosphere on a global scale through … a steady increase in carbon dioxide from the burning of fossil fuels."
Many details have been adjusted, but the basic parameters have not changed. Well, one thing has. In 1965, the concern that greenhouse gases would lead to global warming was a prediction. Today, it is an established scientific fact.