Psychological research shows us that people usually form their opinions based on emotions and then construct after-the-fact rational explanations to justify their opinions (see Jonathan Haidt’s book, “The Righteous Mind”).

In that light, it has been interesting to follow the recent changes in the claims of the deniers of climate change. A few years ago, they often insisted that the Earth was not getting warmer. When evidence for global warming became undeniable, they claimed that the warming was due to natural, not human, causes.

Now, in M.D. Harmon’s column in the Dec. 15 newspaper, I read the next fallback argument: Global warming is beneficial because it will prevent the ice age which, according to a very questionable assertion by a single scientist, is about to begin.

Searching for flaws in an opponent’s argument is a good thing: Critical thinking and debate help lead us to the truth. However, there comes a time to take off the blinders, face the facts, acknowledge that human-caused climate change is a real problem and look for sensible solutions.

As another article in the same issue shows (“Poll: Skeptics say world warming”), most Americans think that time has come, even if Harmon is still in denial.

Harry Vayo

Oakland