Climate change science: what’s in a name?
Posted on 3 July 2013 by gpwayne
"...(language) becomes ugly and inaccurate because our thoughts are foolish, but the slovenliness of our language makes it easier for us to have foolish thoughts."
When it comes to communicating with the public, professionals of all stripes will try to make arcane things simpler, but there are pitfalls, and the unwary often find themselves freefalling into a hole they’ve dug for themselves. Climate change science is no different; the terminology is arcane precisely because it needs to be incredibly specific, and about things that can be as hard to understand, inextricably woven as they are into a dense, complex fabric that covers so much work across so many disciplines.
Scientists employ metaphors, analogies and concepts drawn from everyday life; we all like a good shortcut, a bit of brevity, and scientists are no different. This isn’t a problem within the trade, because it’s a given that everyone knows what you mean; in any case, scientists have an abiding interest in understanding each other, not the least reason being that so much work in scientific disciplines depends on adjacent work done by others.
Where it can be a problem is when it becomes important for the general public to understand enough science for them to appreciate, support and even contribute to a problem that science has identified. In the case of climate change, for example, the public cannot be motivated to systematically reduce their carbon footprint without understanding why they are being asked to do so. Since science is making the demand, albeit by inference, science must also offer that explanation.
To reach the public, we have to create simple messages, distilled out of climate sensitivity, radiative forcing, absorption frequencies, negative mass balance and the like; it’s no wonder we end up with ambiguous terms like global warming, that we talk about 'heat'. Trouble is, this ambiguity also causes all manner of misunderstandings.
Coining the term ‘global warming’ is often credited to Wallace Broecker, who in 1975 published a paper called “Climate Change: Are we on the Brink of a Pronounced Global Warming?” In later years, the media picked up the term and employed it widely, which gave rise to expectations as understandable as they are inappropriate.
When we talk about global warming, the public expect exactly that: everywhere will get warmer. They also expect the warming to be taking place at the surface, in the atmosphere, without taking into account that the oceans cover 70% of the Earth's surface - and that's where 90% of the heat is going. Of course, as we all know, the weather is pretty capricious at the best of times; another problem when we talk about 'warming' is that local effects can be the opposite: when cold arctic air moves south, the Northern Hemisphere can get colder, while warmer air from the south may move northwards, causing the ice to melt - and now we've got warming and cooling at the same time.
Terminology can lead to misunderstanding: after decades talking about global warming, we should not be surprised by scathingly sceptical comments when people suffer bouts of freezing weather, or endure precious holidays shivering in their coats while staring at bleak sand reaching out to an unremittingly cold, grey, stormy sea.
Expecting warming alone is the product of misunderstanding, but a blameless one; the media know an appealing concept when they see one. It is also accurate in a strict scientific sense, because the energy being re-radiated by greenhouse gases is in the bands of radiation we refer to as long-wave, or infra-red. It is also referred to as 'heat' - but that's another word that gives rise to expectations that the evidence doesn't appear to support.
The catalyst for this article is an oft-repeated, but paradoxical claim: that temperatures have been flat for the same period that the Arctic ice has been melting faster, to a greater extent, and recovering less, every year. After all, the rate with which ice melts cannot be independent of temperature. Surely to claim otherwise is an obvious, and really basic error?
Maybe not so obvious. To the public it can appear that there is less warming, because the rate of temperature increase at the Earth’s surface has slowed down in the last decade. Various things have affected the surface temperature - oceanic cycles, for example – but this is less than obvious to the public at large. Even less obvious is this: most of the long-wave radiation reflected back to Earth by greenhouse gases is currently being absorbed as heat and stored in the deep oceans.
There’s also another place where the heat is going. To explain it we can use a different term – one that really cuts to the heart of so many global warming manifestations, referring to energy rather than warming. I’ve started using this term more frequently because sometimes it seems to be a less ambiguous way of talking about the effects of climate change.
Global warming appears to be disrupting global weather patterns. While it isn’t possible to attribute a direct causal relationship between climate change and any specific weather event, it is also impossible for global warming not to contribute in one, very specific, way.
Weather is primarily a system of energy imbalances, areas of high pressure and low pressure constantly seeking, but failing to find, equilibrium. Global warming adds additional energy to the system. That extra energy, now available to the climate, will inevitably pop up somewhere, affect something, and the effect is to change what we’re used to – the frequency of events, the routines, the strength or duration; all these destabilising effects occur because there is now more energy available in the climate system.
Of course, with climate being a chaotic system, we can’t make specific predictions about how or when these changes will occur, any more than we can determine the exact contribution of anthropogenic climate change to climate events that used to be driven by natural variation alone. What we can assert with confidence is that changes will occur.
It is actually impossible for global warming not to contribute energy, and the amount of energy is increasing all the time. The same laws of physics that applied last century apply now: greenhouse gases caused more energy to be retained in the atmosphere before the year 2000, and they must be re-radiating energy now, for their properties do not change over time. Not only that, but there’s more CO2 now than ever - we’ve just crossed the 400ppm boundary, up from pre-industrial levels of around 280ppm, so the amount of additional energy is greater than ever, and increasing by small amounts every day. It’s just that this energy doesn’t always show itself as surface warming. Consequently, it’s also where too much misunderstanding occurs.
Energy is a good term to employ because for lay people it encompasses the destabilising effects in a clear way, a way the public can relate to. Talking about 'energy' makes people think about climate change differently. It isn’t that any one description is better than another; it’s more like getting people to walk round a sculpture to see it from a different angle, to gain another perspective. Talking about energy and melting ice, about energy and storms, about energy and weather, seems to evoke an understanding that puts the effects of climate change on a par with other experiences in our daily lives.
I’m cautious about introducing novel terms, because it can be counter-productive, making things even more confusing despite good intentions. However, when it comes to talking about climate change, using the term ‘energy’ seems to have bridged a gap between science and public discourse without introducing expectations and contradictions that later confuse and confound.
Heat and warming have their place in the lay-person’s lexicon of climate change; perhaps energy too has a legitimate place?