This is an advance summary of a forthcoming article in the Oxford Research Encyclopedia of Climate Science. Please check back later for the full article.
Global warming was not on public or media agendas prior to 1998. In summer of that year, during an unusual heat wave, The New York Times and other major U.S. news organizations saliently reported warnings by NASA scientist James Hansen that the earth is warming. This alarm quickly spread to secondary media and to the news media of other nations. According to the “Quantity of Coverage Theory,” public concerns and governmental actions about a problem rise and fall with the extent of media coverage of that problem, a generalization that is applicable here. Over the next few years, global warming became part of a suite of worldwide issues (particularly the ozone hole, biodiversity, and destruction of rain forests) conceptualized as the “endangered earth,” more or less climaxing on Earth Day 1990. Media coverage and public concerns waned after 1990, thereafter following an erratic course until 2006, when they reached unprecedented heights internationally, largely but not entirely associated with former Vice President Al Gore’s promotion of human-caused climate change as “an inconvenient truth.” By this time, the issue had become highly polarized, with denial or discounting of the risk a hallmark of the political right, especially among American Republicans. International media coverage and public concern fell after 2010, but at this writing in 2015, these are again on the rise. The ups and downs of media attention and public concern are unrelated to real changes in the temperature of the atmosphere.