 A clip from a comedy talk show has gone viral, which isn't all that surprising, but what might be surprising is that the subject matter doesn't sound particularly funny. The video is asking people about health care reform in the United States. The premise of hearing people in the streets say they prefer one plan to reform health care over another doesn't exactly scream comedy, but the genius of the clip is this. While people are describing how they love one plan and hate the other, they don't realize they're talking about the same plan. The interviewer asked about the Affordable Care Act, the name of the plan in the legislature, and also asked about Obamacare, the name associated with the president. But the plans are the same. People's preferences turned out to be different. Sometimes it seems labels matter a lot more than you'd expect. A lot of professional fields have their own jargon which can seem confusing or redundant at first, but often words that might seem to be interchangeable actually have important distinctions. The terminology dealing with changes to the Earth's environment is no exception. Global warming, climate change, and global environmental change can all refer to the present human-caused warming of the planet, but each can also refer to specific aspects of environmental change that the others may not. It's possible to have climate change that isn't global or isn't warming, such as a regional drought. It's also possible to have global warming that's not man-made. The Jurassic got a lot hotter due to greenhouse gases from widespread, long-lasting volcanic activity. Or it's possible to have man-made global environmental change that is neither warming nor climatic, the worldwide loss of wildlife due to hunting and habitat destruction by humans, for example. Maybe this sounds a little complex, but it's a lot simpler than the terminology of the British Isles. I'm still trying to figure that one out. Basically, global warming means an increase in the average surface temperature of a planet. Climate change refers to a change in the statistics of a climate variable over a given area. The variable doesn't have to be surface temperature. It could be precipitation or wind speed. And the statistical property doesn't have to be an average. It could be a change in how often extreme value is reached. The area doesn't have to be an entire planet. It could be just a hemisphere or even a region. So global warming is a kind of climatic change, but not all climate changes have to do with global warming. When you look at the usage of these terms over time in the scientific literature, you see that climate change has been used for a much longer time than global warming. Climate change's usage goes back to the 1920s, and climatic change goes back even further to the 1850s. Global warming is a much more recent term. The modern usage of global warming is often attributed to Wally Brokker from a 1975 paper in the journal Science. However, it was actually used a little earlier, going back to the 1960s. Climate change has been used much more often than global warming. While it might be tempting to think that climate change is used more frequently overall, but global warming has been used more often in association with our present warming, that's not actually the case. The international negotiating system set up to deal with our emissions of greenhouse gases was established back in 1992, and it's called the UNFCCC, or United Nations Framework Convention on Climate Change. Similarly, the scientific group responsible for summarizing the scientific research on the issue is the IPCC, or Intergovernmental Panel on Climate Change. It was established back in 1988. Climate change is the term used most by the scientific community, even though both climate change and global warming describe humans' increasing greenhouse warming. Climate science denialists tell themselves a different story. They claim that scientists used to prefer the phrase global warming, but then they conspired to stop using global warming and instead use climate change. Climate science denialists typically claim that scientists did this because the earth stopped warming up or even cooled. The problem for their narrative, of course, is that the earth has continued to heat up. Heat in the ocean continues to build up, glaciers are on the decline, ice sheets are melting, and raising sea levels. And despite short-term ups and downs caused by natural variability, the global average surface temperature continues to increase. If the climate science denialists were right, you'd expect to see the phrase global warming used by scientists more often than the phrase climate change, and that this preference would reverse if temperatures went down. In fact, climate change has almost always been used more often, and there is no correlation between a preference for the term global warming during times of hotter temperatures. In fact, when temperature was increasing at its fastest rate in recent decades, global warming was actually used less often, not more. The claim by climate science denialists is a classic example of conspiracy theory. In their telling, scientists almost always have an affairs hidden agenda, and they will say whatever they can to advance it. Climate science denialists allege that if mother nature doesn't cooperate with the scientists' claims, they'll just change their terminology to keep their plot going. Such a conspiracy theory depends on its believers not being able or capable of looking at what scientists have actually been doing all along. This conspiracy theory is successful because it oversimplifies a complex reality into a simple falsehood. Believing something that is incorrect because it's easier to understand than a more complex reality is another common characteristic of science denial. The terms climate change and global warming both describe human's increasing impacts from greenhouse gas emissions. Climate change has been used longer and more often by scientists, and they didn't switch terms based on the weather.