Dr. Judith Curry (actual climate scientist), examines a couple of blog posts; what happens if the global warming alarmists are wrong?
They will say that a mechanism called the “greenhouse effect,” was postulated long ago (~1824 by Joseph Fourier) and gained adherents in the late 20th century. They will say that the theory was seemingly invalidated by the decrease in global temperatures from 1940-1975, but that the adherents patched this up by explaining the cooling with pollution, specifically sulfur, from industry.
They will say that the theory was challenged by the noted vast gap between the amount of CO2 produced by civilization and the substantially smaller increase in CO2 in the atmosphere, but that the theory was patched up by examining the increased CO2 uptake by the hydrosphere and the biosphere.
They will say the theory was seemingly invalidated by the evidence that the atmosphere was already nearly opaque in the wavelengths that are absorbed by CO2 and so the additional CO2 could have, on its own, little effect, but that the theory was patched up by positing a feedback mechanism between the small temperature increases directly due to CO2 and the production of water vapor which is the main greenhouse gas.
They will note that the theory of anthropogenic global warming (AGW) proceeded much like any scientific theory (cf. Thomas Kuhn, The Structure of Scientific Revolutions) in that it was modified and patched up and adjusted to fit empirical challenges until it finally collapsed altogether under the weight of incontrovertible evidence. But, the scientific historians will have a new phenomenon to consider, and that is the social and political context of this particular scientific theory.