Talking about climate change

A recent article in the Guardian got me thinking about the language we use when we speak about climate change. Looking back at some of my old articles on Christianity and the environment, I realize that I have not been particularly consistent in how I have referred to it. So, here are some thoughts on talking about climate change.

But first, it may be helpful to distinguish between weather and climate. Weather is what we get from day to day – rain today, sunshine tomorrow (or, since this is Scotland, probably more rain tomorrow). There is a degree of predictability to weather. In the UK, weather forecasts are usually reasonably accurate for the next week or ten days. Beyond that, there is a long-range forecast which is really just a broad-brush account of what we might expect over the coming month. But weather is (or, has been) predictable in another sense. Specifically, it is statistically predictable. It is possible to average the weather results over a number of years (typically 30 years) and arrive at reasonable estimates of the high and low temperatures or the average rainfall in a given month. This sort of statistical analysis allows meteorologists to define a number of climate types, such as such as Maritime, Mediterranean, Continental, or Laurentian. So, for example, Britain has (or had) a fairly typical Maritime climate with cool summers, mild winters, and fairly consistent rainfall throughout the year. To summarize, if weather is what we get, climate is what we can reasonably expect of the weather from season to season and from year to year.

That brings us to climate change. We have reasonably accurate weather records dating back perhaps a couple of centuries. In addition, we have historical, archaeological, palaeontological, and geological records that allow us to infer what the climates were at various locales into the distant past. From these results, it is clear that climates are dynamic. Climates change over time.

I want to underline that climate change is a neutral term. It encompasses both warming and cooling. And it applies both to natural cycles of warming and cooling and to human impact on climates. The term does not imply that such changes are gradual or continuous, but gradualism is a deep-rooted assumption of western science, so there is a tendency to assume that as climates change they will do so in a steady, predictable manner.

The term global warming (or heating) is slightly more specific than climate change. It reflects what has been observed over the past century or more – a steady, gradual warming of climates around the world. Again, note that the term is neutral as to the cause of the warming. My main criticism of ‘global warming’ is that it is too narrow. It focuses exclusively on one aspect of climate. As important are changes in rainfall over time – for example, the progressive desertification of formerly fertile land as rainfall patterns change. Changes in wind patterns and speeds are also significant, resulting, for example, in changing hurricane behaviour. So, perhaps we should avoid this term.

So far, so empirical. But scientists are not content simply to observe and categorize phenomena. Real science seeks to determine the cause(s) of observed phenomenon. In the case of climate change over the past century plus, there is a clear correlation between the degree of warming and the concentration of carbon dioxide in the atmosphere. Granted, correlation does not prove causation, but it has long been known that atmospheric carbon dioxide has a significant insulating effect, so it is reasonable to conclude that this is the cause of the warming. Further, the increasing concentration of carbon dioxide correlates suspiciously well with the industrialization of the world since Victorian times. This has led the vast majority of climate scientists, meteorologists, and atmospheric physicists to conclude that the observed climate change is in large part a result of human pollution. In other words, much of the observed current climate change is anthropogenic.

I have become increasingly uncomfortable with ‘climate change’ and ‘global warming’ because of the tendency to infer from such language that this is a gradual process. So, for example, Mike Hulme of Cambridge University recently asserted that

Rather than imagining cliff edges or crevasses, a better metaphor to think with is the picture of a gradient. Every 0.1C of global warming that occurs increases some of the risks associated with climate change; with every 0.1C avoided some of those risks are reduced.

There is some truth in what he says. But it downplays the very real possibility that relatively small changes in one part of the global climate system can lead to rapid and dramatic changes in climate types around the world.

In view of such a possibility, some people urge us to speak of a climate crisis. They do so from the best of motives, wishing to impart a degree of urgency to the social and political response to climate change. However, I am reluctant to go down this road because it creates the false impression that this is a relatively recent sudden event that can be addressed in the same sort of way as putting an economy on a war footing or responding to a pandemic. It is not. Any adequate response must be a long-term one. Other terms that sometimes appear in the literature are climate catastrophe and climate apocalypse. But this is the language of the fatalist who sees no hope for the human race.

How about referring to our situation as one of anthropogenic climate breakdown? This has the advantage of avoiding the gradualism implicit in talking about change or warming. If we keep pumping energy into the atmosphere and the oceans what we get will not be a simple slow (or fast) increase in temperatures around the world. Rather, what we will see is increasing turbulence and increasing unpredictability. For example, it seems increasingly likely that the Atlantic Meridional Overturning Current (which underlies the Gulf Stream) will collapse by about 2050 (see Detlevsen & Detlevsen 2023). If that happens, it will have a dramatic impact on climates around the world. On the other hand, talking about a breakdown may be misleading. We are not talking about a failure of climate (whatever that might mean) but of dramatic changes in climatic types around the world (which will be unpredictable because of the sheer complexity of the global climate system).

Where does this leave us? Should we talk about climate transformations rather than breakdown? None of the alternatives seem terribly satisfactory. So, for the time being, I think I will opt for the ‘conservative’ position of continuing to use ‘anthropogenic climate change’. But I will keep looking for a better alternative.