One of the things that seems to cause a lot of confusion is the use of the terms “global warming” and “climate change” interchangeably. Frankly, people misuse words all the time and this one example shouldn’t really be that big of a deal. It doesn’t change the science to say global warming when you should be saying climate change. Still, the jargon used by various professions tends to be confusing to those outside the profession.
So I thought the first real article in the new The Truth About Global Warming group is to get some definitions out there so we all know what we’re talking about. I’ll start with the obvious ones and I’ll update this post as questions arise during subsequent commenting and posting.
“Global Warming” and “Climate Change”: As I said, for most people it really doesn’t matter which you use. But technically they are different. Remember your high school SAT questions? Well this is more or less like “orange is to fruit” as “global warming is to climate change.” An orange is just one of the many kinds of fruit. Global warming is just one component of the many things happening that tell us there is climate change. Of course, it’s not really that simple, as we will see in subsequent posts, but it’s a good start.
“Anthropogenic”: Simply put, “man-made.” That doesn’t mean there aren’t natural forces out there also at play. Of course there are natural forces that have impacted climate for millennia. So when scientists say anthropogenic or man-made or human activity they are referring to that component of global warming (or climate change) that is attributable to the things we do – most notably the emission of carbon dioxide (CO2) and other greenhouse gases into the atmosphere. And what 7 billion humans do makes a difference.
“Theory”: This is another word that causes great confusion because most people use it to mean something completely different than do scientists. To most people in common usage a “theory” is like “well, yeah, he could win the game in theory.” In other words, most people use “theory” when they mean more or less a wild guess or at best and educated guess. When a scientist says “theory” he means it is more of a conclusion based on the preponderance (i.e., great majority) of the evidence. It is built on the forming of hypotheses (what we think might explain something we observe), the testing and refining of those hypotheses, and then eventually a pretty solid case for what causes what. In short, things that are pretty well known are called theories, e.g., most people wouldn’t be too worried about the meaning of “the theory of gravity.”
“Scientific Consensus”: Another common point of confusion is when scientists say that there is a strong scientific consensus that climate change is happening and that it is being caused by human activity. When most people hear this they think of a bunch of people sitting around a table discussing where to go for lunch. “Aha, we’ve reached a consensus, it’s definitely Taco Bell!!” In other words, it’s like taking a vote. But that is not what scientific consensus means at all. When a scientist says there is a consensus that means that the issue has been studied for a long time and in many different ways and the sum total of all the collected data and all of the analysis done by multiple people has eventually built up the evidence to a point where it leads so overwhelmingly to a particular conclusion that the vast majority of scientists agree that what the data tell them is true.
“Uncertainty”: Scientists are always looking at “uncertainty.” To most people uncertainty means “we aren’t sure.” But here again scientists use the term differently. As science is always collecting and incorporating new data, nothing can ever be said to be “certain.” But that doesn’t mean we aren’t sure. It just means we aren’t sure about some particular details. We can be very sure that gravity exists, for example, but there is uncertainty as to exactly how and why it exists. Think about what you would do if the weatherman said there was a 90% chance of rain. That means there is still 10% uncertainty, but I’m betting nearly everyone will have their umbrella handy.
Okay, that’s all for now. Any other terms that people think need to be defined? If so, put them in the comments and I’ll add them to the list.
Meanwhile, the USEPA has compiled a list of useful climate change terms that could come in handy.
[This post is part of a series in The Truth About Global Warming, a group on Gather dedicated to explaining what we know, and what we don’t know, about climate change.]