April 2015
gregladen | May 13, 2015Global warming is typically measured at the surface, with data from thermometers all across the land areas and sea surface temperatures combined. That isn't the whole story, of course. Much of the added heat, an effect of human generated greenhouse gas pollution, goes into the upper 2,000 meters or so of the ocean. But we use the surface measurements to track global warming because we have the data for a long period of time, and those data in turn have been linked to longer running but less precise paleo data.
Almost every month for way over a year now has been warm, and April 2015 is no…