Strictly speaking, everything in the February 12, 2018, Hoard’s Dairyman Intel item, “Reader Response: It’s not climate change,” is true. Nonetheless, there is overwhelming evidence of global warming now. The reports of the International Panel on Climate Change, assembled by thousands of scientists over several decades, give a detailed account of the evidence. For instance, although reliable weather records only go back to the 1800s, historical temperatures have been determined from several sources (all agreeing with each other), going back over 5 million years.

— Daniel C. Robie, New York