Summary

I went line-by-line through a mobilisation talk intended for (potential) climate activists in the UK, to check the climate science.
There is a fair bit that’s wrong. There were at least 15 things I found that were factually incorrect, or otherwise misleading.
This is not an isolated case. There have been several cases, across a variety of grassroots groups, where climate activists misinterpret climate science, leading us to build false beliefs.
Specifically, the aspects of science that are most often misinterpreted are:
- How likely various climate scenarios are - For example, statistics from a paper called “Future of the Human Climate Niche” are often used, although this paper uses an emissions scenario (RCP8.5) that has a less than 2.5% chance of becoming reality.
- Tipping points and the myth of “we have 3-4 years to decide the future of humanity” are massively misinterpreted. This particular talk misrepresents the science behind two specific tipping points (ice-free Arctic and Amazon dieback) and falsely claims that drastic and irreversible tipping points will happen in 3-4 years – when there is little to no credible evidence for this.
- Representing climate targets as binaries - 1.5°C or 2°C are often represented as binaries, such that “Either we get it, or it’s gone” and that it’ll be the “end of the world”. This is not an accurate portrayal of tipping points, and not the consensus view amongst climate scientists. Every 0.1°C of mitigation is crucial to reduce risks to vulnerable people around the world.
- The likelihood and consequences of social collapse - Numbers are taken from totally different contexts (e.g. a Civil War in a non-democratic country from 30 years ago) and presented as the truth without any consideration of whether they will actually apply.
- Generally, frequently cited statistics are either not based on actual peer-reviewed science, or only the extreme end of the range is given, instead of the most likely value. This provides a constant air of sensationalism where we only talk about the worst-case scenarios and present them as the most likely outcome.
Another significant issue is the presentation of subjective judgements, with the claim that it is “peer-reviewed science” when this is often not true and adds false credibility.
Overall, the talk has emotive statements combined with misinterpreted information, which I believe could lead to climate doomism and open the door to defeatism.
For example, this international survey of 10,000 young people between the ages of 16-25 show that 56% of respondents think humanity is doomed, and over 50% feel anxious about climate change.
I don’t think this is a good strategy. Defeatism leads to inaction, and that is exactly what the fossil fuel industry would want.
Additionally, I fear it creates a culture of urgency, such that people feel pressed to take action even though some actions can have negative consequences on individuals or the movement overall. A culture of urgency is more likely to lead to cutting corners or poor strategic decisions, which might hamper climate progress overall.
We can make progress, or have already made significant progress, to limit the worst-case scenarios. We need to keep fighting with hope, dedication and courage, and not a constant sense of unproductive terror or guilt.

Note: Since I wrote this, I sent my draft to people within Just Stop Oil who have amended their mobilisation talk, which all seems correct now.

Why is this important (and who I am)

First things first - I’m a climate activist too. I don’t have any weird fossil fuel funded interest in writing this, and I think taking action on climate change is extremely important. I’ve also seen my fair share of climate-related civil disobedience. In addition to that, I’ve written about how effective I think protest movements are in achieving positive social change, and my full-time job is trying to quantify and better understand the outcomes of grassroots movements. This is because I think people power and civil disobedience can be hugely important.

Despite this, I feel uncomfortable when I hear climate science misrepresented by otherwise amazing activist groups. The climate science is bad enough - so we don’t need to exaggerate it any further. Yet, I still often come across (hopefully unintentional) misrepresentations of climate science within activist groups like Just Stop Oil and Extinction Rebellion UK, which I find quite troubling. I’ve often seen it in the contexts of mobilisation talks, internal strategy discussions and attempts to recruit people for a big wave of action. There are some worrying incentives at play here, where saying the most alarming thing to young people might be the most effective way to convince them to take radical action, even though that thing might not be the whole truth.

Why is this important?

I think that we, as a climate movement, need to accurately understand climate science if we’re going to win. I worry that if many of us activists think we only have 3-4 years to avoid total societal collapse, then we’ll make poor strategic decisions that could harm the climate movement overall, or harm ourselves. If we think we’ve missed the boat for climate action, we’ll give up, even though this is the last thing we need to do to help people who will suffer at the hands of climate change. Overall, I believe fear-mongering and climate doomism is not helping us, and could lead to bad choices that actually makes our job of accelerating climate action even harder. Also somewhat ironically, a lot of climate activists attack corporate media for not telling the truth about climate change (rightly so, that’s why I did this), but I think there’s plenty of cases where we’re also not telling the full truth.

Setting the scene

The content I’m analysing is from this video by Roger Hallam from Just Stop Oil, however, the same climate science also features heavily in other campaigns such as Animal Rebellion, Extinction Rebellion and Insulate Britain. Here’s a taster: in this 62-min video, I find at least 15 things which I believe are factually incorrect, misleading or otherwise not supported by science. That’s one incorrect claim every two minutes (the climate science section finishes after 30 minutes). Also to be really clear: this is not an isolated case! I don’t mean to pick on Roger (he’s a great guy in many ways) but he just happens to be one of the few people recording and publishing these talks. Hundreds more very similar talks are being given behind the scenes by many different people (there is a standardised script), so this is a widespread issue.

The first thing to note is how often climate activists selectively absorb new information. Climate activists I know will often always share the worst news and new studies about extreme weather events, tipping points, etc, without questioning the source at all. However, when there is new information about positive trends related to climate change, there is immediate scepticism about who funded this work, how unlikely it is to be true, potential flaws in the methodology, etc. This is a common problem within the climate movement, also known as confirmation bias. Generally, we selectively choose which sources to trust, based on how much they support our existing worldviews. Roger provides a single example of this, by saying “Don’t listen to the experts” whilst at the same time claiming the “world-leading experts” back up his claims. To remedy this, the climate movement really could do with trying to adopt a “scout mindset” and treating all new evidence with the same rigour, whether or not it supports their initial viewpoint.

The actual science

The Future of the Human Climate Niche

Okay so let’s get into the climate science. First, Roger brings up a paper titled “Future of the Human Climate Niche” - a classic paper that is often cited within activist circles [Timestamp: 12:34]. Interestingly, because this paper appears to justify his point, Roger is more than happy to call it “top-notch science” by “world-leading scientists”.

Roger’s main claim from this paper is that 2 degrees of global warming will actually amount to 7 degrees of warming in-land. Is this true? Let’s look at a quote directly from the paper:

“Compared with the preindustrial situation 300 y BP, the mean human-experienced temperature rise by 2070 will amount to an estimated 7.5 °C, about 2.3 times the mean global temperature rise, a discrepancy that is largely due to the fact that the land will warm much faster than the oceans (2), but also amplified somewhat by the fact that population growth is projected to be predominantly in hotter places”.

First of all, there is no science to suggest that “2 degrees of global warming will amount to 7 degrees in-land” [Timestamp: 13:15]. if you divide 7.5° by 2.3 (the figure from the paper), you get 3.26°C – not 2°C of warming like Roger suggests. So just by using simple arithmetic, one can see that Roger is misrepresenting the paper by implying that humans might experience 7.5°C of warming at 2°C, when in reality the paper only suggests this is true for 3.26°C. In other words, the authors of this paper, even assuming the worst possible emissions pathway, are not saying '2 degrees global equals 7 on land', but rather that '3.26 degrees equals 7.5 degrees on land in 2070 [48 years from now]'. For Roger to say 2 degrees equals 7 degrees warming on land is not supported by existing science.

There seems to be some justification in the paper for his statement, that human-experienced temperatures could be substantially higher than the global targets of 1.5-2°C. However, he’s also ignoring important context within the paper that makes his statement misleading.

One such piece of crucial context for the paper in question is that it is modelling the worst-case climate scenarios, also known as RCP8.5. The authors mistakenly refer to it as ‘business as usual’ which probably adds to the confusion of lay-people trying to interpret it. RCP8.5 (also referred as SSP3-8.5 for the socio-economic pathway used in this paper) is a scenario used within climate models that refers to a high-growth and high-fossil fuel future. The problem is that RCP8.5 is increasingly unrealistic, so including it in our models (or in this case, as the main scenario!) gives highly improbable results. For example, Liu and Raftery estimates the chance of society following a RCP8.5 trajectory is less than 2.5% (see the image below, where the red and light red regions cover 95% of the most probable outcomes).

Source: Liu and Raftery, ‘Country-based rate of emissions reductions should increase by 80% beyond nationally determined contributions to meet the 2 °C target’, Nature, 2021. For context, the shaded areas represent 90% and 95% confidence intervals respectively. My annotations are in red.

This is due to some slightly crazy assumptions that RCP8.5 has, such as an increase in fossil fuel consumption that exceeds some estimates of total recoverable fossil fuels. It also assumes a huge increase in coal consumption (2-3x larger than what the most likely scenario predicts), when the International Energy Agency itself says the coal industry is in decline. Long story short, RCP8.5 is extremely unlikely to happen. Therefore, it feels dishonest to present a finding that is estimated to have less than a 2.5% chance of happening, and categorically say this is what is going to happen. If you want to read more about RCP8.5 and how unlikely it is, check out this accessible piece, reporting by Carbon Brief, an article in Nature or this helpful qualification of the human niche paper here. Here are some additional quotes from papers/articles cited above:

“Results suggest lack of fossil fuels to deliver high IPCC scenarios: A1Fl, RCP8.5.” - link
“Accounting for this bias indicates RCP8.5 and other ‘business-as-usual scenarios’ consistent with [...] vast future coal combustion are exceptionally unlikely” - link
“What is disappointing about [the human niche paper] is that the focus is mainly on the worst case scenario, which due to changes in energy generation and efficiency is thankfully no longer realistic.” - link

One of the headline findings of “The future of the human climate niche” is that 1.5-3 billion people would have to move to maintain the current distributions of humans relative to temperature. This is slightly different from calculating how many people will be forced to migrate due to climate change, and the authors themselves note “Obviously, our hypothetical redistribution calculations cannot be interpreted in terms of expected migration”. However, it is still illustrative of the number of people who could face displacement due to increasing temperatures across many parts of the world, which plays a large role in the talk. The paper also largely ignores the ability of humans to adapt to higher temperatures and adaptation measures which means the number of people actually migrating due to climate change is much lower than their estimates.

The upper end of this estimate is calculated using RCP8.5, which based on the above discussion of RCP8.5, is highly improbable (i.e. has a less than 2.5% chance of happening). However, the authors note that the figure of 1.5 billion is calculated using RCP2.6, a strong climate mitigation scenario which is arguably the best-case scenario. Whilst even a 2% chance of three billion climate refugees is awful, we need to accurately communicate that there is a less than 2.5% chance of this happening, rather than convincing young people it will happen. Additionally, more reliable work by the IPCC puts potential forced migration figures at 200 million people, which is more than large enough to not warrant sensationalism.

Source: Hausfather and Peters, ‘Emissions – the ‘business as usual’ story is misleading’, *Nature*, 2020

When do we reach 2°C?

This is a minor but important point about Roger’s claim at 18:48. First, he asks “This will happen at 2°C, when does that happen?” which is quickly followed by him saying “2035, 2040, maybe 2028, you never know”. Again, this might be true for the most extreme 1% of climate scenarios, but his figures are far from the scientific consensus. Analysis by Carbon Brief, on our current emissions trajectories, puts us at exceeding 2°C between 2038 and 2072, with a median estimate of 2052. The median estimate by Carbon Brief, a very respected climate journalism outlet, is 12 years later than Roger’s “most optimistic” estimate and 24 years from his most pessimistic scenario. This might seem like a small point, but in my opinion this adds to a sense of urgency and “we only have X years to save the world” fanaticism or anxiety which is neither healthy nor helpful to an issue. The main reason I think this is due to high levels of climate anxiety amongst young people. For example, this international survey of 10,000 young people between the ages of 16-25 show that 56% of respondents think humanity is doomed, and over 50% feel anxious about climate change. I assume these high levels of fatalism and anxiety leads to higher levels of burnout and inaction relative to lower levels of climate anxiety, but I’m yet to see conclusive data on this.

To reiterate again, I’m all in favour of the precautionary principle and risk management (e.g. even a 5% chance of >2°C is catastrophic for billions of people, so we should act urgently). However, what I would like is an accurate portrayal of climate science, so people can make an informed decision for themselves without counterproductive anxiety or desperation.

The refugee crisis

Using the “Future of the Human Climate Niche” paper, he says “there will be 1 billion (or 1,000 million) climate refugees at 2°C [Timestamp: 18:35]”. Again, he doesn’t add that this paper explicitly wasn’t modelling climate-forced migration. This quote from the authors sheds some light:

“Obviously, our hypothetical redistribution calculations cannot be interpreted in terms of expected migration”

as they explicitly acknowledge that there are many drivers of migration besides climate and weather. In addition, he proclaims it as what we can definitely expect, rather than particularly bad outcomes (which are of course important to account for). This is totally unnecessary as more sensible reports predict 200 million climate refugees by 2050, which is already unbelievably bad!

He continues on to talk about potential death tolls from the refugee crisis. He says that roughly 0.5 million people died in the Syrian civil war and resulting refugee crisis (which seems broadly correct) and then uses this as evidence that 100 million people will die from climate change-related migration [Timestamp 19:38]. The leap here is that if the Syrian Civil War killed 10% of all refugees (0.5 million / 5 million = 10% of the total), therefore 10% of all climate refugees will also be killed. Obviously this is a huge assumption, that all climate refugees will be subject to a bloody civil war and there is very little reason to believe it to be true besides the single example he’s given. For example, we might not face civil wars the same way Syria did, or it might just not scale up the same way when migration is 20x larger or in different areas in the world. For context, the UN International Organisation for Migration finds 4,000 deaths from migration annually (likely an underestimate), which is already a tragedy, yet this is only a fraction of the 90 million people forcibly displaced each year. Using those numbers, he’s claiming the death toll for refugees will be 22,500x larger than it is now. In summary, there are several reasons why this is a nonsensical assumption and again he calls it a fact, which is problematic.

Most troublingly, he concludes this section by saying “There will be 100 million dead, by the time you're in your 30s, according to peer-reviewed papers [emphasis mine]”. The statement is wrong, and borderline dangerous, for a variety of reasons:

There’s no peer-reviewed paper saying 100 million people are going to die due to forced migration from climate change. Roger has incorrectly interpreted “The Future of the Human Climate Niche” as I described above, with an unsubstantiated assumption that 10% of all refugees die to create this number. There is no science to back it up.
He states that it’ll be “by the time you’re in your 30s”. This is just ridiculous. For reference, his audience are students who are about 20 years old. This means within 10-20 years (at his maximum), he expects there to be 100 million people dead from climate change-related migration - again, there is no evidence for this. For reference, the Future of the Human Climate Niche is modelling outcomes in 2070, almost 50 years away.
In summary, comments like this just work to drive fear and anxiety into the minds of young people, by peddling dystopian ideas about what the world is going to be like, with no empirical grounding.

[Trigger warning, this next paragraph is about sexual violence]

Next Roger talks about the fact that “Social collapse means starvation, slaughter and rape” [Timestamp 21:12]. He says that during the Congo Civil Wars, there were 5 million deaths and 2 million rapes and that it is “the reality of what is coming down the road”. Again, there is some pretty worrying fear-mongering here by proclaiming what happened in Congo is going to generalise across the world. It is not clear what source he is using, as the UN estimates for rape during the Congo Civil War is 200,000, 10x smaller than his estimate (and of course still abominable!), although this academic paper does find a number close to 2 million. In short, it’s really not obvious that there will be global social collapse (at least in the way he is depicting it) and that it will lead to sexual violence of the scale he talks about. It seems distasteful, at best, to utilise previous sexual violence as a motivating factor for future action, given that it’s largely taken from a totally different context (a gruesome civil war from the 1990s in a non-democratic and relatively less-developed country).

Whilst anecdotal, I’ve heard first-hand from people who think this level of sexual violence and social collapse will happen in the UK or Europe within the next 30-50 years, which seems unthinkable, and based on almost no factual evidence. Overall, it is likely that climate change will exacerbate sexual and gender-based violence, but in my opinion, we shouldn’t be making fear-mongering claims using dubious figures.

Tipping Points

Next, Roger goes into what he calls “the really bad news”. For context, he’ll be talking about tipping points that might accelerate climate change. He starts with the following quotes:

“For the first time in 10,000, there is an endpoint to human existence” [Timestamp: 24:21]
“This is when all the feedbacks happen, in 3-4 years” [Timestamp: 24:15]

So the implication here is that once feedback loops start taking place, which will happen in about 3-4 years, it will trigger the end of humanity. Let’s see if any of this holds up to scrutiny.

Arctic Sea Ice

He claims “by 2030, or maybe 2035, the Arctic will melt, according to peer-reviewed papers” [Timestamp 24:40]. This is somewhat sensationalist, as the paper he is (probably) citing, states they predict the first summer ice-free Arctic is likely to be 2046, with confidence intervals of 2029-2066. Similar to his previous claims, whilst within the confidence intervals of the study, they are definitely on the extreme end and somewhat at odds with the IPCC literature which predicts this happening closer to 2050. Given his intent is to confirm that tipping points are possible in the next 3-4 years, this is wholly wrong as most predictions put a summer ice-free Arctic at around 20 years later (although the first one could feasibly be in 7 years).

However, more of an issue is that Roger proclaims the following about Arctic sea-ice melting: “That’s it. Game over. No one knows how to refreeze the Arctic, don’t let anyone tell you otherwise [Timestamp 24:53]”. However, peer-reviewed evidence concludes that Arctic sea ice isn’t likely to pose a tipping point and that sea ice can refreeze once melted in summer, contrary to what Roger says. In addition, this website does a good job of providing information on climate tipping points and, based on other peer-reviewed science, finds that a summer ice-free Arctic is only likely to lead to near-term warming of 0.15°C, due to a small increase in radiative forcing, and this is hardly catastrophic. Whilst an additional 0.15°C is obviously bad, it is far from “the end of human existence”. So all in all, there seems to be little-to-no credible evidence that a summer ice-free Arctic will lead to an irreversible tipping point, nor any evidence that ice in the Arctic cannot refreeze. See this article by the National Snow and Ice Data Center for a discussion on why the Arctic can re-freeze in winter - in short, Arctic winters mean no sunlight for months on end, and therefore extremely cold temperatures, which allows the oceans to freeze over again. Additionally, David McKay, an expert on tipping points, also says:

“There is “pretty wide agreement” that Arctic summer sea ice does not have a tipping point, because ice loss is not considered to be self-perpetuating.”

Amazon dieback

Next, Roger discusses how Amazon deforestation at dieback could trigger the Amazon rainforest to turn into a savannah [Timestamp 25:32]. He claims that “according to a peer-reviewed paper, 20-25% loss of the Amazon is a tipping point. The Amazon can’t exist unless it has a minimum size”. The first problem with this is that he is not actually quoting a peer-reviewed paper. He is instead quoting an editorial, written in a journal. To be very clear, editorial pieces do not have to pass the peer-review process, and they’re what you can consider well-informed media pieces, rather than rigorous scientific research. So he gives the element of this being peer-reviewed science when it is simply not true.

Even if you were to believe the researchers who wrote the editorial, they themselves said “If the tree mortality we see continues for another 10–15 years, then the southern Amazon will turn into a savannah”. So again, the authors themselves say 10-15 years, and not the 3-4 years that Roger keeps referring to.

Additionally, other scientists don’t agree with this 20% figure, for example, from this Nature article:

“Not everyone agrees on the 20% figure. Paulo Brando, a tropical ecologist at the University of California, Irvine, says it might require more deforestation to reach a critical point — but the main thing, he says, is to try to keep well away from it. ‘We’re playing an environmental Russian roulette,’ he says.”

“And some other researchers aren’t sure that it’s even possible to define critical deforestation thresholds. “The jury’s out on that,” says Peter Cox, a climate researcher at the University of Exeter, UK, who was one of the first to study an Amazon tipping point in detail in the 2000s. “I don’t think there is currently a strong scientific basis for defining precise thresholds of deforestation or global warming”

For more on Amazon dieback, you can read this Carbon Brief article or this one. Finally, the lead author of the recent impressive Science paper on tipping points himself says that Amazon dieback is likely to only lead to an additional ~0.1°C to global warming (but more regionally).

Overall, Amazon dieback seems like an important issue, mainly for biodiversity reasons, but the level of which a tipping point seems imminent seems overblown. However, Roger is right to focus on human-induced deforestation as this seems like a larger risk relative to dieback.

This all being said, I do think tipping points are concerning, due to the unpredictability and large risks involved. Still, I largely think Roger focuses on the wrong tipping points and largely misrepresents the risks involved. See here for a good explainer on 9 of the most important tipping points, and here for some reasons to act on them now. Probably most importantly, I would encourage people to read this new Science paper (find it open access here) on when we might expect certain tipping points, and their potential impacts. Weirdly, after reading this paper, I felt more reassured that the impact of tipping points weren’t as bad as they’re sometimes made out to be e.g. probably not causing runaway climate change. See below for a quote from the lead author (from his explainer).

End of the world

Roger concludes this “scientific” section with some quotes on the potential impacts:

“This isn’t a campaign, this is the end of the world” [Timestamp: 27:50]
“There are millions of people dying as I speak, it just hasn’t got to this country yet, but it will” [Timestamp: 28:08]
“Either we get it or it’s gone. It’s a binary. That’s what all the world’s leading scientists are saying”. [Timestamp 28:55]

Okay so there are several things wrong with this section:

First, I don’t think there’s any evidence to show that millions of people are dying from climate change right now, anywhere in the world. Again, this is sensationalism and fear mongering which I don’t think is the best motivator of action.
Secondly, and more importantly, it’s not a binary. Every single 0.1°C matters – because as Roger alludes to, climate damages increase exponentially at higher temperatures. Therefore we should never give up, because every additional 0.1°C reduction in temperatures means we are helping huge amounts of people. This framing feels worrying - as it implies there is a point at which we should give up because we’ve missed the boat for 1.5°C or 2°C. This is absolutely harmful and will cause suffering to people around the world if we think this way. As Dr. Jacquelyn Gill puts it, defeatism leads to inaction. Who does inaction benefit? Only the fossil fuel industry, and stakeholders invested in the status quo.

“All of the world’s leading scientists” don’t think it’s a binary, or that it’s the end of the word - and it’s untrue to say otherwise. There are several IPCC authors or otherwise experts who are optimistic we can make (or already have made) important progress on climate change. Just see the quote below from Johan Rockstrom, director of the Potsdam Institute for Climate Impact Research (and often quoted by activist groups) saying just the same, and every tenth of a degree is crucial for vulnerable people across the globe.

Climate messaging

I believe that alarmism and more dire messages around worst-case scenarios can work, but I also don’t think they’re the best strategy to use at all times. There’s some academic literature to indicate it does motivate action, and Extinction Rebellion clearly did pretty well by mobilising using fairly “alarmist” or dire language of extinction. Despite this, when young people are facing such high levels of climate anxiety, or feelings of doom, this makes me doubt whether it’s the best strategy for the climate movement in the long-term. For example, dire messaging about worst-case scenarios might be a useful motivating tool to raise the alarm and kickstart people into action, but when the UK already has 75% of people concerned about climate change, maybe we should adapt our messaging slightly. An example of this is shown in this paper, where more alarmist messaging was seen to work best in politically conservative people, who had a low baseline of risk perceptions around climate change.

There’s already some evidence that alarmist messaging leads to less support for climate action, but I think none of this is particularly bulletproof. Overall, I’m the most concerned about the number of people who are reporting that “it’s pointless to act, we’re screwed anyway”, which often comes from a place of misinterpreted science. From my very naive point of view, it seems that now that concern from climate change is much higher than what it was 5 years ago (but still not high enough arguably), we should adapt our messaging such that it’s slightly less doom-and-gloom and more hopeful.

Conclusion

That’s all the science I’ll critique. I’m aware that it was a lot, so congratulations if you’ve read this far. I’ll end this with some other articles you can read for more information, if you want to explore these topics further.

To recap, I think the climate science is worrying, and millions of people are at risk of suffering. However, doomism, in my opinion, is not a winning strategy, so it’s crucial that we avoid this in the climate movement. I believe we have the power to avert the worst impacts of climate change, and create a better future for all. Especially if we tackle the problem with all possible solutions, and with the required optimism, dedication and courage.

Further reading:

Stop Telling Kids They’ll Die - Hannah Ritchie
Good news on climate change - John Halstead and Johannes Ackva
Challenging Climate - Podcast with Hannah Ritchie
We will fix climate change - Kurzgesagt
- Although there are quite a few things that could be improved in this video - see this doc.
Pessimism is a barrier to progress - Hannah Ritchie

Acknowledgements

Thanks to Will and Ellie McAree for very helpful comments on this! All errors are my own.

Appendix

Potential temperatures in London [not in the standard Just Stop Oil script]

Roger uses the 7°C on land figure to incorrectly talk about how average temperatures will change in London. First, he claims that an average day in London is going to be 30°C [timestamp: 15:15]. It’s slightly confusing where he got this number from, but working backwards from his initial point that temperatures on land will be 7°C higher than today, I think he’s trying to say that the average temperature in London is 23°C – which is just totally wrong. The mean annual temperature of London is 10.8°C, in which case he says it’s 12°C higher than it actually is.

He then goes on to say it’s going to be 45 degrees on a hot day in London in 15-20 years time [Timestamp: 15:19]. Now this is wrong for several reasons:

The paper he’s referring to is modelling temperature increases for 2070, 48 years away. I have no idea why he’s trying to reduce 48 years to 15 years with no rational or scientific basis.
As mentioned above, he incorrectly starts with an average UK temperature of 23 °C, then adds 7°C from the paper, then (now I’m speculating) he adds another 15°C to get a “hot day” in summer. This would give you 45°C (23+7+15=45°C), however, he starts at totally the wrong point!
Even using his arbitrary addition of 15 degrees for a hot day in summer, and the very unlikely 7°C from the Human Niche Paper (which has less than a 2.5% chance of being that large), we would still only get a summer average temperature of 33°C (11°C London average + 7+ 15 = 33°C). You might say that an extreme heatwave will add another 12°C to that, but at this point we’re largely plucking numbers out of thin air
But the most important point is from above - this scenario has less than a 2.5% chance of happening so to say things like “that means it will be 45°C on a hot day [emphasis mine]” is incredibly misleading when he’s talking about extreme scenarios with little probability of becoming true.

A few caveats are that: extreme heat and heat waves are still incredibly bad, and they will get more likely due to human-caused climate change! Roger is directionally saying the right things, but he’s either a) totally misinterpreting the science or b) sensationalising it to make a point. In my opinion, neither are good.

It’s also important to mention our recent UK heatwave with a temperature maximum of 40.3°C, but this was an extreme weather event, not your average “hot day”. That said, extreme weather events will get more likely and frequent due to climate change.

Understanding Social Change

Climate activists don’t always accurately…