text: The highest recent rate of warming based on its linear trend occurred during the 170-month period that ended about 2004 2006, but warming trends have dropped drastically since then. There was a similar drop in the 1940s, and as youll recall, global surface temperatures remained relatively flat from the mid-1940s to the mid-1970s. Also note that the mid-1970s was the last time there had been a 170-month period with a global warming rate that lowbefore recently.