Etymology


The term global warming was probably first used in its modern sense on 8 August 1975 in a science paper by Wally Broecker in the journal Science called "Are we on the brink of a pronounced global warming?".[133][134][135] Broecker's choice of words was new and represented a significant recognition that the climate was warming; previously the phrasing used by scientists was "inadvertent climate modification," because while it was recognized humans could change the climate, no one was sure which direction it was going.[136] The National Academy of Sciences first used global warming in a 1979 paper called the Charney Report, it said: "if carbon dioxide continues to increase, [we find] no reason to doubt that climate changes will result and no reason to believe that these changes will be negligible."[137] The report made a distinction between referring to surface temperature changes as global warming, while referring to other changes caused by increased CO2 as climate change.[136] This distinction is still often used in science reports, with global warming meaning surface temperatures, and climate change meaning other changes (increased storms, etc..)[136]

Global warming became more widely popular after 1988 when NASA scientist James E. Hansen used the term in a testimony to Congress.[136] He said: "global warming has reached a level such that we can ascribe with a high degree of confidence a cause and effect relationship between the greenhouse effect and the observed warming."[138] His testimony was widely reported and afterward global warming was commonly used by the press and in public discourse.[136]