The Internet is full of references to global warming. But we don't use the term “global warming” much here at Climate Reality. Instead, we prefer to use "climate change."
Global warming and climate change – while closely related and sometimes used interchangeably – technically refer to two different things:
To a scientist, global warming describes the rise in average surface temperatures we see resulting from human emissions of greenhouse gases.
Although “global warming” seems to have first appeared in a 1957 newspaper editorial, the term is widely attributed to Wallace Broecker’s 1975 paper “Climatic Change: Are We on the Brink of a Pronounced Global Warming?”
Broecker's term was a break with tradition. Earlier studies of human impact on climate had called it "inadvertent climate modification." This was because while many scientists accepted that human activities could cause climate change, they did not know what the direction of change might be. Industrial emissions of tiny airborne particles called aerosols might cause cooling, while greenhouse gas emissions would cause warming. And in the middle of the twentieth century, scientists wondered which effect would dominate.
Through most of the 1970s, few were certain. So "inadvertent climate modification," while clunky and dull, was an accurate reflection of what we knew.
The first decisive National Academy of Science study of carbon dioxide's impact on climate, published in 1979, abandoned "inadvertent climate modification." Often called the Charney Report for its chairman, Jule Charney of the Massachusetts Institute of Technology, it declared: "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."
In place of “inadvertent climate modification,” Charney adopted Broecker's language. When referring to surface temperature change, Charney spoke of "global warming." When discussing the many other changes that would be induced by increasing carbon dioxide, Charney called them what they were: "climate change."
During the late 1980s, one more term entered the lexicon: “global change.” This term encompassed many other kinds of change in addition to climate change. Reflecting the understanding that climate change could be part of an even larger picture, when the US Global Change Research Program was approved in 1989, climate research was a key theme area.
“Global warming” became the dominant popular term in June 1988, when NASA scientist James E. Hansen testified to Congress about climate, specifically referring to global warming. 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." Hansen's testimony was very widely reported in popular and business media, and after that, popular use of the term “global warming” exploded. “Global change” never gained traction in either the scientific literature or the popular media.
Temperature change itself isn't the only severe effect of changing climate. Changes to precipitation patterns and sea levels are likely to have much greater human impact than the higher temperatures alone. For this reason, scientific research on climate change encompasses far more than surface temperature change. So "global climate change" is the more all-inclusive and scientifically accurate term. Like the Intergovernmental Panel on Climate Change – the UN’s body for assessing climate science – we've chosen to emphasize global climate change, and not global warming.
Don’t fall prey to the idea that the increased popular usage of “climate change” means global warming is no longer happening. Both climate change and global warming are still a reality.
Whether referred to as "global warming" or "climate change," the consequences of the enormous changes currently being observed in Earth's climate system are undeniable. That’s why we need our leaders to listen to the science and accept reality – instead of splitting hairs over terminology.