February 4, 2014, by Brigitte Nerlich
Global warming is dead, long live global heating?
This post emerged from a weekend conversation between Mike Hulme, Brigitte Nerlich and Warren Pearce.
It is also available as a pdf.
There has been a lot of talk recently about a so-called ‘pause’ or ‘hiatus’ in global warming. Some argue that it poses a serious challenge to established climate science and may undermine its theories and predictions. Others see it only as a challenge to those unable to read graphs. And others argue that it indeed poses some challenges to climate science that, once addressed, may well enhance its theory and predictions. Some scientists belonging to the latter group try to provide explanations for this apparent hiatus and, in the processes, have utilised an apparently new term in an attempt to clarify their position: ‘global heating’.
In this post we discuss how global heating is used in comparison to global warming; we shall look at its semantic history and we shall examine the communicative problems it may pose and the confusion it may lead to.
Explaining the hiatus
One of the most prominent articles using the new phrase was published in December 2013 by Trenberth and Fasullo entitled An apparent hiatus in global warming? The authors favour ‘global heating’ as a ‘more scientifically accurate’ headline description of human influence on the Earth’s climate, allowing for the paradox of a planet which is heating and yet displaying virtually no atmospheric warming at the surface because of heat uptake by the deep ocean:
The authors ask:
“Has global warming stalled? Or is it entirely expected that natural variability rears its head and can offset warming for a decade or two?”
In part the answer depends on what we mean by ‘global warming’. For many it means the global mean temperature increases. But for anthropogenic climate change, it means the climate change resulting from all kinds of human activities, and it is now well established that by far the biggest influence occurs from changes in atmospheric composition, which interfere with the natural flow of energy through the climate system [IPCC, 2007]. Referred to as ‘radiative forcing’ by scientists, the biggest effect comes from increasing carbon dioxide in the atmosphere because carbon dioxide is a greenhouse gas (GHG) […] Preindustrial values are estimated to average about 280 ppmv (parts per million by volume) but values in 2013 have exceeded 400 ppmv, a 43% increase, mainly from the burning of fossil fuels. Several other GHGs (methane, nitrous oxide, and chlorofluorocarbons) have also increased from various human activities, while tiny particulates (aerosols) in the atmosphere can cause both warming by absorbing radiation or cooling by scattering and reflecting radiation back to space. The result is a positive (down) energy imbalance at the top-of-atmosphere. In that sense ‘global warming’ really means global heating. Increasing global mean temperature is but one manifestation of the effects […] The analysis in this article does not suggest that global warming has disappeared; on the contrary, it is very much alive but being manifested in somewhat different ways than a simple increase in global mean surface temperature.” (Emphasis added)
We cannot remember anyone ever using or talking about ‘global heating’ in public before 2013, but this does not mean that nobody did. So we began to check the uses of global warming and global heating over time.
Global warming
It seems that, according to the Oxford English Dictionary, ‘global warming’ was first used in 1952. “San Antonio (Texas) Express 28 Apr. 2/5 Scientists who are studying global warming trends point out that not a single iceberg was sighted last year south of Parallel 46.” It was first use in the journal Science came in June 1971. Since then it has become the dominant term in climate change debates, especially in the US.
According to the most authoritative source on the state of the English language, the Oxford English Dictionary (3rd edition, 2009), ‘global warming’ means :
A long-term gradual increase in the temperature of the earth’s atmosphere and oceans, spec. one generally thought to be occurring at the present time, and to be associated esp. with side effects of recent human activity such as the increased production of greenhouse gases.
However, climate scientists seem to have used the phrase in a more restrictive sense as meaning: a rise in global mean surface air temperature or “mean planetary temperature” (Broecker, 1975). There may therefore be a difference between the general (and popular) understanding of global warming in the broad sense as referring to overall Earth system warming in both atmosphere and oceans (what one may call ‘global warming 1’) and the more specific scientific usage of global warming in the narrow sense of surface air temperature warming (what one may call ‘global warming 2’), which can lead to confusion.
Global warming 1, broad meaning (à la OED) – refers to warming of the whole Earth system: atmosphere, cryosphere and oceans
Global warming 2, narrow meaning (à la Broecker and other climate science literature) – refers to warming of global mean surface air temperature; refers to the lowest part of the atmospheric boundary layer
The more narrow scientific meaning came to dominate policy discourses around limiting global warming to 2 degrees, determining the carbon budget and so on. (Interestingly, Wigley et al (1981) drew attention to the danger of focusing on surface air temperature rather than full atmospheric heat content – he didn’t mention ocean heat — in a short commentary in Nature).
Global heating
The OED has no entry for ‘global heating’, but when we checked the Lexis Nexis News database we found a first use in 1975, from the magazine Chemical Week (Hester, 1975), in the context of a discussion of ‘propellants’:
The global heating, Ramanathan explains, would result from the ‘greenhouse effect’ in which the fluorocarbons would absorb solar radiation but not allow heat to escape back into space. Many scientists fear that an atmospheric buildup of carbon dioxide released by the world’s industries could also lead to runaway heating of the earth by the same process.
The latest attested uses on Lexis Nexis refer to the Trenberth and Fasullo paper (but the phrase global heating is also used in Australia in the context of the most recent heat wave). Between 1975 and now ‘global heating’ was used 392 times in English Language news, while global warming was used on more than three times as many occasions in the past week. However, it seems clear that originally global heating and global warming were quasi-synonyms, but that global warming won out in the end.
As a Dot Earth blog post by Andrew Revkin shows, global heating was still used as a quasi-synonym of global warming in 2008. Revkin quotes from a 2006 interview with James Lovelock, for example, who said:
Warming is something that’s kind of cozy and comfortable. You think of a nice duvet on a cold winter’s day. Heating is something you want to get away from.
However, global heating is used here to stress the dangers of global warming. This could be seen as a stronger or hypberbolic meaning of global warming.
Interestingly, we found the link to the 2008 post inside a 2013 Tumblr by Revkin which highlights a recent NOAA graph relating to ‘global heating’. Here we find the present-day use of the phrase by some climate scientists which is now beginning to spread more widely, namely as indicating that greenhouse gas emissions are affecting the energetics of the whole Earth system.
This means that there are three meanings of ‘global heating’: ‘global heating 1’ as an early synonym for global warming; ‘global heating 2’ as a more emphatic meaning of global warming, highlighting the real (dangerous) meaning of global warming (à la Lovelock); and ‘global heating 3’ as referring to a different (‘more scientifically accurate’ à la Trenberth) description of human influence on the Earth’s climate which takes into account ocean heat content, cryosphere melting, etc., as well as atmospheric temperature.
Global heating 1 – early synonym for global warming (à la Chemical Week)
Global heating 2 – emphatic or strong meaning of global warming (à la Lovelock)
Global heating 3 – new use of the phrase (à la Trenberth) in the context of the ‘hiatus’ debate. Essentially a new name for global warming 1.
What does ‘global warming’ really mean and do we need ‘global heating’?
Having surveyed the various meanings of ‘global warming’ and ‘global heating’, it becomes clear that the debate about the so-called ‘pause’ in global warming only seems to work in the context of debates about ‘global warming 2’ (or surface air temperature warming), rather than ‘global warming 1’ (or total system warming). In order to explain the apparent ‘pause’ in ‘global warming 2’, scientists are now looking for a phrase with a more extended meaning. Since ‘global warming 1’ is not current usage, they are proposing ‘global heating 3’ as the ‘real’ meaning of ‘global warming’. Scientific explanations of the pause now draw on new data covering the whole system, including ocean temperatures at various depth, energy required for ice melt, and so on.
There are several difficulties related to the emergence of global heating as an attempt to explain recent scientific understandings of climate change:
(1) Overall we have a recipe for confusion, between ‘global warming 1’ (total system warming) and ‘global warming 2’ (global air surface warming), but also between ‘global heating 1’ (as a synonym ‘global warming 1’), ‘global heating 2’ as a more emphatic way of talking about ‘global warming 1’ and ‘global heating 3’ as a new phrase proposed to replace ‘global warming 2’. The problem for climate change communicators will therefore be a double one: To explain the difference between the broad sense of global warming and the restrictive sense of global warming and the need for a new term (global heating) for the broader meaning.
(2) Another difficulty is that those publics who have been attentive to the issue of global warming understand it through the lens of science and the language of global surface temperature (global warming 2). Policy talk about 2 degrees, popular books about 6 degrees, the popular slogan ‘mitigate for 2, adapt for 4’ and annual press releases telling us the global surface air temperature for the year all feed into this popular understanding of climate change. If scientists now say that what really matters is the amount of heat (energy) accumulating in the whole system, and not merely global surface temperature, then public understandings of global warming will likely be disrupted.
(3) Climate policy has, up to now, been built around measurements of global warming 2 (derived mostly from land and marine surface thermometers) and yet is now being supposed to draw upon scientific insights into global warming 1/global heating 3. Scientifically, the basic physics related to greenhouse effect may not have changed, but one can see how critics may think the goalposts are being moved. Questions may also be asked as to why global warming was ever defined in a restrictive way anyway. Was it because of restrictions on what scientists where able to measure at the time? Was it because of science communication, as we understand air temperature (the language of quotidian weather) better than energy content (the language of a physical system)? Was it to facilitate a policy goal that was easy to comprehend? Most likely it was all three, which is why a move to global heating now may be problematic.
Footnote: we use a dictionary definition from the OED in this post, but during the research it became apparent that definitions of global warming vary substantially between dictionaries. We will be looking at this issue in a future post.
[This blog post is not only linked to the work carried out within the Leverhulme Making Science Public programme, but also to a systematic study of climate change a complex social problem supported by the ESRC]
SELECTED REFERENCES
Broecker, W. S. (1975). Climatic change: are we on the brink of a pronounced global warming? Science, 189(4201), 460–463. doi:10.1126/science.189.4201.460
Hester, N. E. (1975, September 24). More propellants heat. Chemical Week, 18.
IPCC. (2007). Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. (S. Solomon, D. Qin, M. Manning, Z. Chen, M. Marquis, M. Averyt, M.Tignor & H. L. Miller, Eds.). Cambridge: Cambridge University Press.
Lynas, M. (2008). Six Degrees: Our Future on a Hotter Planet. London: Harper Perennial.
Russell, C. S., & Landsberg, H. H. (1971). International environmental problems—a taxonomy. Science, 172(3990), 1307–1314. doi:10.1126/science.172.3990.1307
Shaw, C. (2013). Choosing a dangerous limit for climate change: Public representations of the decision making process. Global Environmental Change. Retrieved from http://www.sciencedirect.com/science/article/pii/S0959378013000034
Trenberth, K. E., & Fasullo, J. T. (2013). An apparent hiatus in global warming? Earth’s Future, 1(1), 19–32. doi:10.1002/2013EF000165
Wigley, T. M. L., Jones, P. D., & Kelly, P. M. (1981). Global warming? Nature, 291(5813), 285–285. doi:10.1038/291285a0
There is now a translation into Czech available here, kindly produced by Barbora Lebedová on her blog: ‘Science Blog – Research shapes the future‘
[…] February) ‘Global warming is dead; long live global heating?’ Together with Brigitte Nerlich and Warren Pearce, I explore the changing language of climate […]
As I’ve been talking about the “pause” since around 2006 – and could may have been the first to use it, I might as well explain its origin as far as I am concerned. The origin was a simple discussion about trends – with only five years warming from the IPCC 2001 report, I didn’t expect the conversation to last longer than “but five years isn’t long enough”.
Instead, on the particular blog I received an outright denial “no it is not cooling”. I then found that over the years as I mentioned the 5 , then 6 then 7 year trend, the response was always outright denial – none of those supporting global warming appeared able to do a simple linear regression.
There must have been some article in a newspaper that mentioned it as I eventually tried to get a section in about “present cooling”. Realising that had no chance of getting past the censors, I tried to find a neutral term that did not imply that warming had definitely stopped, and hit upon “Pause”. Again any idea that warming had “paused” was rejected outright.
The importance of the pause has never been the trend. It has instead been the reaction of those who could not bring themselves to admit the fact that the linear regression of the surface temperature did not show warming.
And now what 8 years later, rather than just saying “it’s just a trend”, you have to write a whole article trying to explain it.
The reason the “pause” is so important, is not in the actual trend, but the psychological block which has prevented people even admitting this simple trend.
A real scientist only cares that they have accurately calculated the trend. They don’t get hung up about whether or not it’s a “pause”. It’s just a gradient. So why then, has it taken 8 years for global warming academics to admit that the temperature was not going up?
Why was it so impossible for them to admit a simple trend, and why now that they have do they spend so much time trying to “excuse it”.
This shows a level of emotional attachment to a certain interpretation which is not appropriate for science.
My contribution to this post was from the point of view of a linguist noticing a certain emergent trend (if one can call it this) in language use relating to debates about climate change in general and about what some have called a pause in particular. We shall have to wait and see whether this short term trend will lead to a new way of talking about climate change.
As a linguist, Bridgette, do you also see a trend in the popular media to use “climate change” instead of “global warming” or “global heating”? In my view, “climate change” is too vague to be useful in communicating the urgency of dealing with this existential problem. I’d like to see something more like “climate disruption”.
Hi
Here is an article on global warming/climate change by Lorraine Whitmarsh. However, it is now a decade old. I haven’t systematically followed the fate of these two words since then, I am afraid. However… when you look at Google trends you’ll see that the two phrases are used almost equally since around 2010. Before that, around 2007-2009 there was a real spike in searches of global warming, around the time of some seminal events in climate change politics. By contrast there was a big spike in searches for climate change in around 2017 – Trump? etc. etc. But all this would need a closer look. As for a better word… yes, climate disruption is much better. I myself use climate chaos. Others use climate breakdown (George Monbiot). As you say climate change is too vague, as change can also be positive, which is not the case here.
What’s “appropriate for science” Mike Haseler, is to attempt faithful empirical descriptions and to address mechanisms underlying causality.
However I do take the point that attempting to encapsulate complex phenomena with a single word or short descriptor is not very helpful either for communication or understanding.
So for surface temperature it’s appropriate to recognize:
1. The large anomalous El Nino of 1998 skews surface temperature trends downwards in subsequent years if 1997/1998 is used as a starting point for trend analysis.
2. That surface warming in the regions of the world covered by, for example, the HadCRUT4 temperature record has been small since around 2005.
3. However that inclusion of measures of (especially) Arctic warming indicates that global surface warming hasn’t really “paused”,* although the rate of surface warming has decreased somewhat in the last decade.
4. That the continued accumulation of solar energy by the oceans indicates that an enhanced greenhouse-forced energy imbalance driving global warming (however we wish to define this) persists.**
5. That this energy imbalance can only be “closed” by warming of the surface and atmosphere, and so the fact that the surface hasn’t warming quite so much during the last decade or so simply indicates that we are “storing up” surface warming to come, especially as we continue to increase atmospheric [CO2] at a prodigious rate.
*e.g. http://onlinelibrary.wiley.com/doi/10.1002/qj.2297/pdf
**e.g. http://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/index.html (see e.g. 0-2000 m Global Ocean Heat Content data in graph 2).
Seems to me that “global warming” remains the descriptor of choice. Then it only requires that one qualifies this with an indication of whether one is referring to surface warming or total “Earth system” warming (i.e surface and warming), in any particular case.
Obviously we’re interested fundamentally in surface warming since that’s where we live! However we need to recognize the meaning and implications of any decreased rate of surface warming, in the context of wider knowledge and understanding.
There needs to be some allowance for a more complete description of things if we wish to communicate meaning properly!
Yes, I agree, making a distinction between surface warming (or atmospheric warming perhaps) and whole system warming might be useful in contexts where disambiguation is needed.
The danger with introducing “a new way of talking about climate change” is that this can be seen as spin.
That is certainly a danger!
From the 1910’s to 1940 the earth “warmed”. From the 1940 to mid 1970’s the earth “cooled”. From the mid ’70’s to roughly 2,000 the earth “warmed”.
It’s the oceans.
This discussion is all contrived to explain away the hiatus-pause or cessation of global warming, now in its seventeenth year. And that despite the highest atmospheric carbon dioxide levels in history. As a scientist I am telling you what this means: the theory of greenhouse warming does not work and must be abandoned. And if it does not work now it is clear that it never did work. The question then becomes explaining the previous warming we keep hearing about. It follows that all previous warming we have been told about is simply natural warming, misidentified by eager acolytes of the global warming mysterium. To make this clear, we need to bring in radiation theory of physics. It tells us that in order to start a greenhouse warming you must simultaneously increase the amount of carbon dioxide in the atmosphere. This is necessary because the absorbance of a greenhouse gas in the infrared is a property of its molecules and cannot be changed. We already noted that there has been no warming this century. Looking at the temperature history of the twentieth century we see that the warming was not uniform but occurred in sudden leaps. The first warming of the century started in 1910, raised global temperature by half a degree, and stopped in 1940. The second warming started in 1999, raised global temperature by a third of a degree Celsius in only three years, and then stopped. That is a total of 0.8 degrees Celsius warming for the entire century. And it is all natural warming, not man-made because there was no increase of atmospheric carbon dioxide either in 1910 or in 1999, the starting dates of warming. How do I know this? It is easy. Mauna Loa has been recording concentration of atmospheric CO2 since 1958 and has published it as the Keeling curve. Law Dome ice cores extend this to earlier years. Both curves are extremely smooth at the critical dates for initiating greenhouse warming. Conclusion: greenhouse warming does not exist and never did. Belief in its existence is nothing more than pseudo-science.
That’s a very interesting comment Arno, especially in your use of “pseudoscience” in the last sentence. Warren Peace and I were discussing this word on a recent thread here:
https://blogs.nottingham.ac.uk/makingsciencepublic/2014/01/24/how-to-do-things-with-gifs/
Warren suggested (somewhat ungrammatically!) that “pseudoscience” is “those people which scientists seek to exclude”. You’ve suggested that “belief in the existence of greenhouse warming” is “pseudo-science”. My view is that pseudoscience can be identified, often very easily, by consideration in the light of contemporary scientific knowledge, and that pseudoscience is often based on false premises and misrepresentation of scientific knowledge (sometimes deceitful, but not necessarily so).
We could address your assertions in a similar vein. You’ve suggested based, I think, on the high surface temperature in 1998 resulting from an extremely strong El Nino, that the “cessation of global warming” is “now in its seventeenth year”. But one might look at, for example, the NASA Giss surface temperature record:
http://data.giss.nasa.gov/gistemp/graphs_v3/Fig.A2.gif
…and note that the warmest temperature on record is 2010. So using your argument based on selecting single years, one might more accurately assert that the temperature hiatus has lasted for 3 years. Of course as I indicated in my response to Mike Haseler above, one really needs to make a rather more considered assessment of scientific evidence before drawing conclusions.
Your assertion that all 20th century warming “is natural warming, and not man made” based on the smoothness of the Mauna Loa and ice core CO2 record, is an argument based on a false premise, namely that surface temperature should march in lock-step with atmospheric CO2 on very short (annual/decadal) timescales. That would absurd and no climate or atmospheric scientist (let alone any reasonably well-informed individual) would consider such a thing. …and so on…
Your ‘Difficulty (2)’ which is addressing “those publics who have been attentive to the issue of global warming understand it through the lens of science” doesn’t hit the actual problem. Those who have scientific or engineering background, and anyone who turns to scientific explanations of CO2-Global-Warming would first find that the basic theory is that CO2 will worsen the Earth’s energy budget.
Step-one for a scientific explanation is energy. And not all energy is converted into heat. Problems then ensue because climatologists talk and write in terms of heat, average global temperature, computer-model outputs etc. in ways that don’t make sense. Which leads to lack of trust.
The 2nd step finds that there’s zero evidence that natural variation couldn’t cope with what little additional warming is created. And zero historical evidence that current temperatures are ‘unprecedented’.
Of course, ClimateGate didn’t help the scaremongors cause.