I couldn’t find any “climate crisis” in the IPCC’s most recent Assessment Report
The public rhetoric surrounding climate change has reached fever pitch in recent months. The rise to prominence of the impressive young climate activist Greta Thunberg has perhaps been the catalyst for this most recent convulsion of public outcry over what has been dubbed our ongoing “climate emergency”, or “climate crisis”. The nascent international movement known as Extinction Rebellion has staged numerous high-profile protests and publicity stunts in a number of countries, causing considerable disruption and garnering plenty of media attention. What is perhaps most noteworthy about the movement is its name — Extinction Rebellion. We have had environmental and climate-related demonstrations before of course, and the rhetoric has for a long time been one of urgency, doom and gloom. But over recent months, the upward shift in gears has become particularly noticeable. Increasingly, climate change is being framed as an impending existential threat. Not only to humans, but to life on earth as we know it (see, for instance, the recent WWF advert [linked below] claiming that we are “destroying our world”). In the minds of many of these activists and those who support their cause, we are literally on the cusp of wiping ourselves and everything else out in the historical equivalent of the blink of an eye due in large part to our burning of fossil fuels.
Assuming they are right, it is perfectly understandable then that they would resort to the most disruptive protest tactics they can think of. It is perfectly understandable that they would harangue and harass politicians and the board members of oil companies. What does it matter that they block roads, storm parliament, or interrupt corporate AGMs, when the sky is already falling? In the face of imminent extinction, these are trivial inconveniences. In the face of imminent extinction, almost any means is justifiable! So these kinds of stunts are but a drop in the ocean in the context of the kind of action that is really needed.
This shift in rhetoric has even been formalised by The Guardian newspaper. In a recent article titled “Why the Guardian is changing the language it uses about the environment”, Environmental Editor Damian Carrington informs us that “The Guardian has updated its style guide to introduce terms that more accurately describe the environmental crises facing the world. Instead of “climate change” the preferred terms are “climate emergency, crisis or breakdown” and “global heating” is favoured over “global warming”, although the original terms are not banned.” The fact that such a prominent publication has all but mandated this kind of language suggests that we are now at a point where, such is the certitude that apocalyptic-scale crisis is imminent, that even to risk understating that crisis is the secular equivalent of blasphemy.
From what I have read, and from listening to those belonging to movements such as Extinction Rebellion, the consensus seems to be that global warming is sure to result in extreme and out of control weather patterns and climatic convulsions that could potentially spell the end for humanity and other species. At the very least we can expect more frequent and intense cyclones and hurricanes, more frequent and intense floods and droughts, rapid sea-level rise, more extreme precipitation events and deadly heatwaves. And perhaps what is most cause for concern is the fact that we are now at serious risk of triggering a runaway warming, and all its attendant extreme weather consequences. According to such groups, this is not just hyperbole. This is not their opinion. It is, they claim, lifted straight from the oft-invoked scientific consensus.
Noise and Signal
Until recently, my understanding of climate change had come for the most part from second-hand opinion pieces: newspaper editorials, YouTube lectures and debates, articles in popular science magazines, and a range of other popular sources claiming to have distilled the essential message of the scientific community. I imagine this pattern is representative of many in the general population. However, I have for a long time also been dissatisfied with what I see as an excess of clumsy and careless language in the public discourse on this subject; and a failure to identify the politically salient questions. I was always puzzled, for example, about the relative infrequency with which the following kinds of questions were raised and addressed by those who were most vocal about the threat:
(i) Assuming we continue using fossil fuels, what is the net economic and social cost of climate change likely to be over the next, say, 100 years; and is that net cost of climate change less than or greater than the net economic and social cost of cutting carbon emissions to near-zero and switching over to renewable energies in that same time period? How exactly do they stack up? (Not even experts in the area who are alarmed about climate change deny that there will be considerable costs associated with a switch over to renewables. For example, the BBC’s Environmental Correspondent writes that avoiding more than 1.5 degrees celsius of warming “ will be hugely expensive — but the window of opportunity remains open.” The problem is that “huge expense” is not just a baldly financial category. It has immediate humanitarian and social implications. Even a marginal increase in fuel costs for a person living in poverty can be devastating. Reliable use of rudimentary farming machinery in developing nations is highly fuel-price sensitive. Hospital equipment running reliably is highly fuel-price sensitive. And I know of no analysts who are highly confident in their predictions about the compared net long-term socioeconomic costs of warming vs. wholesale transition to renewables and the lost economic development associated with the latter).
(ii) Are there are any expected benefits associated with higher concentrations of CO2 in the atmosphere, and if there are, what are their respective magnitudes and probabilities?
(iii) Are there any negative environmental impacts associated with the manufacture of and supply chain for renewable energy facilities and infrastructure — especially in the context of a rapid ramp-up in their production? If so, what are their projected magnitudes, and how do those impacts compare with the impacts of fossil fuel sources?
The facts that the world is warming, and that anthropogenic emissions in the form of increased C02 concentrations have accounted for much of that warming, seemed to me both uncontroversially true and relatively trivial in and of themselves. What is of major concern are the effects of that warming, the magnitudes of those effects, and the chances that our activities might reach a tipping point and trigger some kind of irreversible, runaway warming. I had assumed based on what I had read and heard that there would indeed be many negative consequences — increased hurricane activity and extreme weather events, more frequent and severe droughts and floods, and sea level rise being among the most dire. However, I had also understood that this would all play out relatively gradually, and that the costs would be significant but not existential in scale. With the recent shift in pitch of public alarm, I figured that it must have been much worse than I had previously thought. I therefore felt it incumbent upon myself to cut through all the second-hand noise and go straight to the source. That way I could see for myself what Extinction Rebellion, Greta Thunberg and their fellow-travellers had presumably seen and been deeply shaken by…
The IPCC’s Fifth Assessment Report (AR5) and The Special Report on Global Warming of 1.5°C
In order to get the most robust and up-to-date view on the scientific picture, I decided to cross-reference a reading of the IPCC’s most recent complete assessment report (“AR5" for short) with the more recent Special Report on Global Warming of 1.5°C. The former is a far more extensive document, while the latter is intended to build on the foundation set in AR5 with updates where appropriate in light of more recent research. The more recent report has a narrower thematic focus on the impacts of global warming of 1.5°C above pre-industrial levels. Having considered the pertinent sections in the more recent report, I could not find statements that directly contradicted or qualified the corresponding statements I have excerpted below from AR5. The following are all taken verbatim from the AR5 Technical Summary, with emphases added (indicated in parentheses) in places for the purposes of the subsequent discussion. The page numbers for each excerpt are included:
Temperature Extremes
“It is very likely that the number of cold days and nights has decreased and the number of warm days and nights has increased on the global scale between 1951 and 2010. Globally, there is medium confidence that the length and frequency of warm spells, including heat waves, has increased since the middle of the 20th century, mostly owing to lack of data or studies in Africa and South America. However, it is likely that heat wave frequency has increased over this period in large parts of Europe, Asia and Australia.” (p. 46)
Sea level rise
“GMSL [Global Mean Sea Level] rise for 2081–2100 (relative to 1986–2005) for the Representative Concentration Pathways (RCPs) will likely be in the 5 to 95% ranges derived from Coupled Model Intercomparison Project Phase 5 (CMIP5) climate projections in combination with process-based models of other contributions (medium confidence), that is, 0.26 to 0.55 m (RCP2.6), 0.32 to 0.63 m (RCP4.5), 0.33 to 0.63 m (RCP6.0), 0.45 to 0.82 (RCP8.5) m (see Table TS.1 and Figure TS.15 for RCP forcing). For RCP8.5 the range at 2100 is 0.52 to 0.98 m. Confidence in the projected likely ranges comes from the consistency of process-based models with observations and physical understanding. It is assessed that there is currently insufficient evidence to evaluate the probability of specific levels above the likely range. Based on current understanding, only the collapse of marine-based sectors of the Antarctic ice sheet, if initiated, could cause GMSL to rise substantially above the likely range during the 21st century. There is a lack of consensus on the probability for such a collapse, and the potential additional contribution to GMSL rise cannot be precisely quantified, but there is medium confidence that it would not exceed several tenths of a metre of sea level rise during the 21st century.” (p. 49 — emphasis added)
Abrupt/Runaway Changes
“There is information on potential consequences of some abrupt changes, but in general there is low confidence and little consensus on the likelihood of such events over the 21st century.” (p. 70)
“It also remains very unlikely that the AMOC [Atlantic Meridional Overturning Circulation] will undergo an abrupt transition or collapse in the 21st century for the scenarios considered (high confidence).” (p. 70)
“It is very unlikely that CH4 from clathrates will undergo catastrophic release during the 21st century (high confidence). On multi-millennial time scales, such CH4 emissions may provide a positive feedback to anthropogenic warming and may be irreversible, due to the difference between release and accumulation time scales.” (p. 71, emphasis added)
“The response of boreal forest to projected climate change is also highly uncertain, and the existence of critical thresholds cannot at present be ruled out. There is low confidence in projections of the collapse of large areas of tropical and/or boreal forests.” (p. 71)
“The reversibility of sea ice loss has been directly assessed in sensitivity studies to CO2 increase and decrease with Atmosphere–Ocean General Circulation Models (AOGCMs) or Earth System Models (ESMs). None of them show evidence of an irreversible change in Arctic sea ice at any point.” (p. 71)
“The available evidence indicates that global warming beyond a threshold would lead to the near-complete loss of the Greenland ice sheet over a millennium or longer, causing a global mean sea level rise of approximately 7 m. Studies with fixed present-day ice sheet topography indicate that the threshold is greater than 2°C but less than 4°C (medium confidence) of global mean surface temperature rise above pre-industrial.” (p. 72 — emphasis added)
“The complete loss of the Greenland ice sheet is not inevitable because this would take a millennium or more; if temperatures decline before the ice sheet has completely vanished, the ice sheet might regrow.” (p. 72)
Floods and Precipitation
“Confidence in precipitation change averaged over global land areas is low prior to 1951 and medium afterwards because of insufficient data, particularly in the earlier part of the record… Further, when virtually all the land area is filled in using a reconstruction method, the resulting time series shows little change in landbased precipitation since 1901. Northern Hemisphere mid-latitude land areas do show a likely overall increase in precipitation (medium confidence prior to 1951, but high confidence afterwards). For other latitudes area-averaged long-term positive or negative trends have low confidence.” (p. 40)
“There continues to be a lack of evidence and thus low confidence regarding the sign of trend in the magnitude and/or frequency of floods on a global scale over the instrumental record. There is high confidence that past floods larger than those recorded since 1900 have occurred during the past five centuries in northern and central Europe, western Mediterranean region, and eastern Asia. There is medium confidence that modern large floods are comparable to or surpass historical floods in magnitude and/or frequency in the Near East, India and central North America.” (p. 112)
Drought
“Compelling arguments both for and against significant increases in the land area affected by drought and/or dryness since the mid-20th century have resulted in a low confidence assessment of observed and attributable largescale trends. This is due primarily to a lack and quality of direct observations, dependencies of inferred trends on the index choice, geographical inconsistencies in the trends and difficulties in distinguishing decadal scale variability from long term trends.” (p. 112)
“Under the Representative Concentration Pathway RCP8.5, projections by the end of the century indicate an increased risk of drought is likely (medium confidence) in presently dry regions linked to regional to global-scale projected decreases in soil moisture. Soil moisture drying is most prominent in the Mediterranean, Southwest USA, and southern Africa, consistent with projected changes in the Hadley Circulation and increased surface temperatures, and surface drying in these regions is likely (high confidence) by the end of the century under RCP8.5.” (p. 112)
Tropical and Extratropical Cyclones
“There is low confidence in long-term (centennial) changes in tropical cyclone activity, after accounting for past changes in observing capabilities. However over the satellite era, increases in the frequency and intensity of the strongest storms in the North Atlantic are robust (very high confidence). However, the cause of this increase is debated and there is low confidence in attribution of changes in tropical cyclone activity to human influence owing to insufficient observational evidence, lack of physical understanding of the links between anthropogenic drivers of climate and tropical cyclone activity and the low level of agreement between studies as to the relative importance of internal variability, and anthropogenic and natural forcings.” (p. 113)
“While projections indicate that it is likely that the global frequency of tropical cyclones will either decrease or remain essentially unchanged, concurrent with a likely increase in both global mean tropical cyclone maximum wind speed and rainfall rates, there is lower confidence in region-specific projections of frequency and intensity. However, due to improvements in model resolution and downscaling techniques, it is more likely than not that the frequency of the most intense storms will increase substantially in some basins under projected 21st century warming.” (p. 113, emphasis added)
“Over the last century there is low confidence of a clear trend in storminess due to inconsistencies between studies or lack of long-term data in some parts of the world (particularly in the Southern Hemisphere (SH)). Despite systematic biases in simulating storm tracks, most models and studies are in agreement that the global number of extratropical cyclones is unlikely to decrease by more than a few per cent.” (p. 113, emphasis added)
Key Uncertainties
“There is generally low confidence in basin-scale projections of significant trends in tropical cyclone frequency and intensity in the 21st century.” (p. 115)
“There is low confidence in semi-empirical model projections of global mean sea level rise, and no consensus in the scientific community about their reliability.” (p. 115)
What are the takeaways from all of this?
Before addressing some of the specifics above, I want to pre-empt one potential and important misunderstanding. This article is not intended to imply or convey the message that there are no problems associated with global warming and climate change. Nor is this article (as should be abundantly clear by now) intended to deny the reality of anthropogenic global warming and climate change. Clearly the world has been warming in an anomalous manner over the last 150 years or so, and most of that warming can be confidently attributed to human industrial and agricultural activity. This is the locus of the popular 97% consensus. And it’s a consensus I defer to. Moreover, I know of no serious person who would deny that a changing climate is likely to present challenges and costs that will have to be addressed.
Rather, the point of this article is to suggest that the popular and mainstream discourse on climate change has reached a tenor of panic and alarm that is far removed from what appears warranted by the actual scientific literature on the subject. The imagery in the WWF advert linked above very effectively conveys what I think most people still envision when they think about climate change. More frequent and violent hurricanes, more frequent drought, more frequent flooding, huge waves engulfing coastal areas and wiping out low-lying populations. The problem is that none of this seems warranted by the IPCC’s most recent complete report. Or at the very least, none of it can be confidently predicted. For example, about the most that one can say with respect to hurricanes/cyclones and droughts is that, by the end of the century, we are confident that in some regions the frequency and/or intensity of cyclones will increase; and by the end of the century, we are moderately confident that in some regions droughts will be more intense and/or frequent. But these are hardly apocalyptic predictions; and note that they are consistent with the possibility that in other regions, we will see corresponding decreases (in fact, as much is implied by the rather awkwardly phrased statement that “most models and studies are in agreement that the global number of extratropical cyclones is unlikely to decrease by more than a few per cent.” Phrased more naturally, AR5 concludes that there is confidence that the global number of extratropical cyclones is likely to decrease by a few percent).
Of course, there are some things quoted above that we should be concerned about. The question is how concerned should we be? For instance, take temperature extremes. Clearly there is evidence that climate change will lead to an increase in the number of extremely hot days (heatwaves), as well as a decrease in the number of extremely cold days. With respect to the former, certainly we need to start preparing for that and adapting. However, the latter should not be overlooked either — and there, it is likely that fewer extremely cold days in and of itself is a good thing (as one would intuitively expect). This is because, holding other things constant, cold is responsible for more deaths than heat. According to one recent study, more temperature-attributable deaths are caused by cold (7·29%, 7·02–7·49) than by heat (0·42%, 0·39–0·44) — roughly 20 times more deaths. Fewer extremely cold days is therefore likely to reduce the number of deaths from cold. However, it does not follow that a warmer world in the future is therefore necessarily a good thing overall in terms of temperature-attributable deaths. This is because of the way that populations and wealth are distributed globally. As it happens, the overwhelming majority of the poorest nations reside in warm climates. They are already relatively unaffected by cold, but certainly exposed to the negative effects of extreme heat. Therefore, if we’re looking at absolute numbers, we’re likely to see an increase in overall temperature-related deaths even factoring in the reduction in cold-related deaths.
What does this imply? Does it constitute grounds for panic? Hardly. What it underscores is the degree to which socioeconomic conditions in large part determine vulnerability to temperature-attributable death. It is far from self-evident that the best approach to pre-empting that vulnerability is to try and prevent the warming from taking place by drastically cutting fossil fuels. One alternative, which should be glaringly obvious in any other context, is to ensure that those vulnerable nations can economically develop sufficiently to better deal with heatwaves when they do occur. I won’t presume here the optimal manner to pursue that objective — I don’t suppose to know the optimal energy mix, for example. I simply point out that to assume drastic cuts in fossil fuels as logically entailed by the danger posed by heatwaves is premature at best.
What about sea level rise? Again, AR5 does predict sea level rise. Doesn’t this warrant alarm and urgent, drastic action? Not necessarily. Firstly, as indicated in other areas, there is little-to-no evidence for rapid sea level rise or imminent, runaway warming. Notice too the range of rise “predicted”— “the rise for 2081–2100 (relative to 1986–2005) for the Representative Concentration Pathways (RCPs) will likely be in the 5 to 95% ranges”. In other words, the rise in that period could be anywhere from 5% of the rate from 1986–2005 to 95% of that rate! This is a rather strange form of prediction. It is essentially an admission of ignorance regarding specifics. The only thing that the IPCC seems certain of is that there will be some rise in sea level over the next century or so. How much and what rate of rise is a matter of considerable speculation. But even assuming a median point between 5 and 95%, that rate of sea level rise is still far from alarming in the sense of being likely to rapidly overwhelm and inundate coastal areas. As Bjorn Lomborg likes to point out, when we look back over the 20th century and ask what were the most world-changing and cataclysmic events, almost no one responds “the sea level rose by X centimeters”. That’s because the rise was gradual, incremental, and coastal areas adapted accordingly. The rise over the next century or so is likely to also be gradual. It may be less gradual, but that is about the most drastic thing that one can say. Once again, as the sea encroaches (while previously ice-covered land masses are newly exposed), we will adapt our land use accordingly. There will be costs — of course. But again, are those costs so high that it warrants dismantling and reconstructing the entire global economy and energy infrastructure? I find that conclusion highly implausible.
I will not delve too deeply into the remaining points. And again, I do not pretend to have addressed all potential consequences of climate change. Considering that our climate is essentially omnipresent — it touches and affects essentially everything — it is virtually certain that there will be other costs incurred. But then again, as we saw in the case of extreme cold and extratropical cyclones, there may well be several counterbalancing benefits too. It is certainly not an analytical truth that all effects of a changing climate must be necessarily negative. That is an open empirical question, and must be investigated and demonstrated. What I hope comes across in the above excerpts taken as a whole is the degree to which confidence in many of the predictions regarding weather and climate extremes is in fact low. There is certainly not a “scientific consensus” that we are facing imminent self-destruction as a result of such effects. Far from it.
Why the alarm?
All of this invites the question: if there really isn’t a scientific consensus that we are, or are even likely to be, facing imminent doom and self-destruction as a result of climate change, then why is there a growing certainty in the popular discourse that in fact we are? Answering that question fully is beyond the scope of this article. It strikes me as a highly complex psychological and sociological matter. However, there are some speculations that strike me as plausible as a first pass.
Firstly, there are undoubtedly a proportion of people who are anxious to see the demise and/or replacement of the prevailing global economic order. Such people already have a strong ideological aversion to the system. As such, any further data that confirm their existing beliefs are likely to be welcomed and embraced. If global warming can be attributed to the prevailing economic order, then that’s yet another reason to be opposed to it — and perhaps more importantly, another reason why they do not have to abandon and overhaul their own worldview and political perspective. Confirmation bias is certainly a prevalent and well-established psychological force. Undoubtedly, there are at least some engaging in this debate who are manifesting this tendency, and it may go some way to explaining their obstinate commitment to the near-apocalyptic vision.
This interpretation is reinforced by the fact that, in many cases when one presents such people with even the possibility that things are not as bad as they thought, their response is not one of reserved optimism or relief. The response in general is not “oh really? That would be wonderful if it’s true. Can you show me the evidence so that I can confirm that we are not after all facing imminent doom?” More typically, the response is something like: “You’re a climate denier!”; “Who’s paying you off!?”; “You must be a neo-liberal stooge or a redneck conservative religious nut!”; “How f*cking dare you!? Your denial is tantamount to a crime!” Or perhaps some snide, sarcastic variant of the above.
A second factor may be something like the following (although I suspect this is a weaker psychological force). Often, when faced with real-life catastrophes or threats of real-life catastrophe — especially on a societal scale — there is a certain kind of adrenaline that comes with it. It’s something like a macrocosmic manifestation of the ambivalent “rush” we feel when we watch horror movies. We are for whatever reason (I suspect evolutionarily) perversely drawn to and fascinated by tragedies and looming threats and unknowns. I suspect that, in the case of the visions of global catastrophe and disaster associated with climate change, there is an element of being drawn to such visions in the same way we are drawn to epic horror movies and the like. I think this is perhaps evidenced in the cinematic depiction of disaster conveyed in the WWF advert above. This in turn provokes an immediate sense of urgency, a sense of unquestionable and clear collective purpose, and thus constitutes an incredibly powerful basis for setting aside relatively trivial group differences in order to come together and overcome a common and looming threat.
Finally, there is a tendency — whether knowingly or naively — to conflate two distinct things: the (accurate) claim that there is overwhelming scientific consensus that the world is warming due to anthropogenic factors; and the (inaccurate) claim that there is overwhelming scientific consensus that we are headed for imminent doom and widespread human/animal suffering as a result. What might start out as innocent enough discursive shorthands (“what do you think about climate change?”; “do you believe in global warming?”) can end up fudging and obfuscating several nuanced, complex and logically distinct subjects. Global warming then becomes a conceptual package deal, whereby acceptance of the reality of warming necessarily entails acceptance of the reality of consequent catastrophe.
I tentatively suspect that all of this taken together goes some way towards explaining the popular perception of climate change. Climate change has become for many a fundamental part of their political and social identity. To challenge or question it is therefore perceived as a personal affront, as an attempt to undermine their clear sense of purpose and urgency and solidarity with others. I don’t doubt that there are other institutional and political factors at play. I also don’t want to be seen as supposing that I am impervious to political biases. I too have my ideological prejudices. [In the interests of full disclosure, I consider myself somewhere on the spectrum between classical liberal and what is sometimes called left-libertarian. I support a combination of liberal markets and a strong welfare state in the form of a Universal Basic Income.] However, my conclusion is not that nothing should be done. And indeed I admit that, if a near-existential threat were looming, rejection of my preferred political-economic system would be on the table. And I approached the IPCC report with that attitude — that were I to find that near-existential disaster were almost certainly looming (or even considerable suffering for the world’s poor above what they already endure), then I would have to seriously revise my political viewpoint. Fortunately (and I say fortunately from the perspective of humanity, not from the perspective of my ideological proclivities), that appears not to be the case. We face challenges, certainly. But it is unlikely that they are not manageable, especially under assumptions of continued rapid economic development for the world’s poorest. My fear is that the catastrophic alarm will continue unabated. And that well-meaning activists in their panicked fervor to see something done, will end up supporting the prescription of a blunt cure that is far worse than the actual disease.
