A lot has been said on this topic, but I feel there is a lot left to say. I used to avoid using the phrase “global warming” in favor of “climate change“, because I thought the former was too politically charged. But after some reflection, I think “global warming” is the better term, and this post outlines my reasons.

Let me first define what I’m talking about. In this post I am specifically referring to what happens when emissions of gases that strongly absorb/emit thermal radiation (i.e. greenhouse gases), such as carbon dioxide (CO2) and methane (CH4), from human activity (i.e. anthropogenic) are accumulated in the atmosphere. We know from intensive study of the carbon cycle and good record-keeping that CO2 has increased from human activity. The confusion, controversy, and continued exploration is focused on providing explanation and attribution of the consequences of this accumulation. My concern here can be simply stated:

How should we refer to the consequences of increased CO2?

Several articles on this topic focus on the political history, in which “climate change” was introduced by certain conservative groups to downplay the significance of the issue. Personally, I’m not interested in this narrative, and I’m not interested in placing blame or demonizing anyone. I’m only concerned with which term is a “better” way to describe the phenomenon.

Social science research shows that how we refer to this issue strongly influences how people feel about it. “Global warming” has been shown to be better at grabbing listeners’ attentions. Should public opinion dictate what words and phrases we use to discuss important scientific issues? I would argue that it should, and so the more specific term “global warming” seems like the better choice when talking about anthropogenic CO2.

“Climate change“ might seem like the better term because it encompasses a wide variety of changes that we care about. For example, loss of property from sea level rise may be very costly for certain regions, but the localized problems will not seem obviously connected to a slow net warming of the planet. To me, “climate change” allows a disconnect between the cause and consequences. A skeptic group can argue for responding to “climate change“, while still arguing that “warmists” can’t be trusted.

The generality of “climate change” is most likely why it is used so much more often than “global warming“. The figure below shows my own little meta-analysis of how these terms appear in titles of research articles. Note that the left and right axis are very different.

Time series of the number of publications that have the phrase “climate change” (left axis) or “global warming” (right axis) in the title. Data was taken from webofknowledge.com.

As a side note, I wish there was an easy way to separate out articles that appear in atmospheric science journals, but apparently I need some sort of special account on webofknowledge.com to do any serious analysis. An interesting aspect of the above figure is that the use of “global warming” leveled off in the 90’s. You might say there was a… “global warming” hiatus…

Some articles make a clear distinction between the two terms, in that “global warming” describes a cause, and “climate change” describes an effect. In this sense, there’s no problem with using both terms. But, since “climate change” can be used to talk about climate shifts not caused by increased CO2, I feel that “global warming” is the better term to use when discussing the science that surrounds the issue.

Both terms comes with their issues when addressing a skeptical audience. Every time there is a blizzard, people can be heard saying “where’s your global warming now?” Alternatively, skeptics love to use the phrase “The climate is always changing!” (which is kind of strange argument when I think about it…) I’ve also heard skeptics say things like “[they] can’t even decide what to call it!”, implying that the scientific consensus can’t possibly be settled if we can’t agree on our marketing strategy.

In either case, I think it’s important to include the word “anthropogenic” when talking about this, because warming can happen for a variety of reasons, and on a variety of timescales. It’s hard to confront stubborn arguments against the acceptance of global warming that revolve around statements like, “the climate is always changing”. Of course it is! Who ever said it’s not changing? This tatic is a way to cast doubt, which can be used to dismiss any argument. When talking to skeptics, it is very hard to convey how recent warming is occurring on a scale that is uncharacteristic of natural warming cycles, which is why it is important to stress the word “anthropogenic”.

Disclaimer: I realize this is a stupid semantic issue, but I thought it was interesting, so I wrote about it.