Arguments
10 year anniversary of 97% consensus study
Posted on 15 May 2023 by John Cook, BaerbelW
10 years after and still going strong!
Ten years ago today - on May 15, 2013 - our team published the paper Quantifying the consensus on anthropogenic global warming in the scientific literature (Cook et al. 2013). Little did we know that our publication, organized as a citizens’ science project and published open access thanks to speedy crowdfunding support from Skeptical Science readers, would make such an impact and still be of much interest ten years later. But, that it’s still of interest is quite visible when visiting the Environmental Research Letters website where, together with other consensus-related publications, Cook at al. (2013) has been consistently among the Top 10 papers read. Other indicators of continued interest are the download numbers which currently are at 1.39 million and the Dimensions stats:
The text on the Dimensions page is interesting:
"This publication in Environmental Research Letters has been cited 778 times. 22% of its citations have been received in the past two years, which is higher than you might expect, suggesting that it is currently receiving a lot of interest.
Compared to other publications in the same field, this publication is extremely highly cited and has received approximately 121 times more citations than average."
Some highlights
A lot has happened since the paper was published and we’ve written about several milestones before, so here is just a short list of our favorite memories:
In April 2014, ERL announced that our paper was voted their best article in 2013.
In May 2014, John Oliver aired a sketch called “Climate Change Debate” in his “Last Week Tonight” show, which featured our paper. The video has been viewed more than 8.8 million times.
In April 2016, authors of a number of consensus studies teamed up to co-author Consensus on consensus: a synthesis of consensus estimates on human-caused global warming (Cook et al. 2016) in response to Tol (2016). Interestingly, our “Consensus on consensus” paper has thus far been downloaded 826,650 times while the paper causing it to be written only shows 42,925 downloads.
In July 2019, our 97% consensus paper crossed 1 million downloads - quite an achievement for a scientific paper. It was the most downloaded paper not just at Environmental Research Letters but across all the ~80 journals published by the Institute of Physics.
Baseless attacks on our paper - and other consensus studies - kept coming and in some cases, the attackers didn’t even know which of the studies they were attacking as illustrated in this Cranky Uncle cartoon:
In 2021, we put together a video summarising the history of the scientific consensus on climate change - both the studies finding consensus and the persistent attempts to cast doubt on consensus:
In November 2022, we published a long-overdue explainer about what a scientific consensus actually is. Just to re-iterate the main point: A scientific consensus is not a show-of-hands as it looks like in the cartoon below at first sight! It's more like "Yes, because of the evidence we all agree that humans are causing climate change". The consensus is not evidence of global warming – it evolved over more than 100 years from the evidence.
This month, the basic rebuttal version was updated to - among receiving the “At a glance” section - now include mentions of several more studies examining the scientific consensus on human-caused global warming, with all of them finding a strong consensus of at least 97%.
Let’s end with this cartoon, perfectly illustrating what we’ve been up against for the last 10 years:
We are sure that this pattern will continue for the time being!
Plus ca change....
I notice that if you look at the total number of downloads of the later "Consensus on consensus" paper and the Tol paper that triggered it, 95% of the downloads are for "Consensus on consensus". That's gotta hurt.
If you sum all of the (100-percentages) up you get over 30 percents of papers disagree with AGW. And if assume that they are only 95% certain, because I heard somewhere about p values and confidence limits at 95%, then we can take another 5% off for each of those 9 papers, which is 45%, add the initial 30% and we get 75% total papers disagree with AGW. Flawless denier math!
Please don't ban me, this is sarcasm / humour.
On the 10th Anniversary of the 97% consensus study maybe it is time to find out what percentage of climate scientists believe that global warming will be catastrophic ?
Gordon @ 3:
Ah, yes, the good old "catastrophic" squirrel.
I'll tell you what: if you can provide us with your definition of "catastrophic" - and it is a clear, well-expressed definition - then maybe we'll pay some attention to you.
Until then, we'll just assume that you are playing debating games. "Catastrophic Anthropogenic Global Warming" (CAGW) is the center square in ClimateBall Bingo.
Perhaps "catastrophic" should only be used when quantified by % .
# 100% catastrophic = the Sun goes supernova
# 90% catastrophic = moon-size asteroid strikes Earth
# 30% catastrophic = sea level rises 2 meters
# 20% catastrophic = Floridian gets re-elected President
# 5% catastrophic = price of gasoline exceeds $8 per gallon
# 0.1% catastrophic = earthquake tsunami destroys New York.
Something along those sorts of lines. Quantification essential.
You can't intelligently manage to talk about it, if you can't measure it.
Bob @4,
Can we use the Skeptical Science definition ?
The consequences of climate change become increasingly bad after each additional degree of warming, with the consequences of 2°C being quite damaging and the consequences of 4°C being potentially catastrophic.
Eclectic #5 - nice!
The trouble with terms like "catastrophic" is that one man's minor catastrophe is another's Bad Hair Day... but yes I think we can agree about the Sun going Nova (or, the likelier outcome, to red giant). There are a lot of subjective terms out there - 'dangerous' is another.
John Mason @7 ,
You are quite right ~ "going red giant" is vastly more likely (tho' gradual)
. . . so I rate that as only # 97% catastrophic.
~Was going to say # 95% , but 97% is an almost inescapable climate figure .
Gordon @6 ,
your quote ["potentially catastrophic"] is not a definition.
Better to give your own words to say what you mean by catastrophic.
As John Mason points out, the word means many different things to different people ~ and it is impossible to have an intelligent discussion unless everyone has a common concept of what's being talked about. Otherwise, words like catastrophic are just "slogans for shouting" ~ and nothing gets achieved (apart from the exercise of shouting).
Is it "catastrophic" if sea level rises 2 meters in 1000 years, or do we have enough time to adjust? It would be catastrophic if sea level rose 2 meters in 5 years. You need an amount and a time. I think a cash amount is easiest to start with. Since it is a forecast you need a percentage chance. If the chance of catastrophe is only .01% most people would not care.
Is it more likely than not that climate damages worldwide exceed $10 trillion before 2050 or $50 trillion by 2100?
You could have a single value or two possible catastrophes. Or you could do human cost:
Is it more likely than not that Climate Change will result in over 100 million refugee by 2050? Or perhaps over 50 million deaths?
I think items like ecological damage are too hard to estimate. Single items like likely sea level rise are too specialized.
Scientists would have to offer heir opinion on topics that are not heir specialty. For example Zeke Hausfather gives good temperature descriptions, we want his thoughts on the chances of catastrophe. We only want opinions from experts, not just the man on the street or some paid fossil shill.
Michael @10 ~ yes, points taken.
But the question of time scale : that's probably best viewed by the usual legal yardstick of "reasonable" ~ that which would be reasonably expected over a reasonable timespan in reasonably predictable circumstances, as viewed by a reasonable person (or better, by a reasonable climate scientist). Does that sound reasonable?
A future sea level rise of 1 meter has been closely estimated as displacing around 230 million people. Presumably a rise of 2 meters would displace well over twice that number, and would destroy a far greater amount of fertile farmland into the bargain. Perhaps not a problem if occurring over 2,000 years ~ but not-quite-unbearably-catastrophic if occurring over the more reasonably likely timespan of 200 years.
In short, the term "catastrophic" is nearly useless.
Beg to differ on (your) suggestion of catastrophe definition by dollar scale. Too much room for endless wrangling there, whether the figures be $10 Trillion or $50 Trillion or $500 Trillion (not to mention if these figures are additional costs or partly-substitute costs +/- dependence on future unknowable technologies). Besides, oooooodles of zeros can have a stultifying effect on the average mind [such as mine].
Dollar scale is inferior to scale by Deaths & Displacements & Destroyed farmlands.
Gordon can't or won't provide a definition of "catastrophic"? I'm shocked, I tell, shocked.
Maybe he does not know the definition of "definition". Here it is, from Wiktionary:
While I am at it, let's look at "catastrophic" (also from Wiktionary):
At which point we may as well add "catastrophe":
Still rather general - losing one's house in a flood may be catastrophic for the people living in that house, but is not catastrophic for another person half way around the world.
...but such vagueness is a feature for Gordon, not a bug. By avoiding his own definition, he gets to use it as a "slogan for shouting" (to use Eclectic's words). He gets to avoid any real discussion of the implications of warming, can repeatedly take positions such as "I don't think that is catastrophic" without saying what he thinks is catastrophic, and just use the slogan as an attack on the significance of the studies mentioned in this blog post.
Gordon is introducing "catastrophic" as a red herring. He is engaging in misdirection (Look, squirrel!):
...and just in case anyone does not know what a squirrel is (it's not just "a small animal with small ears"):
Any further discussion of whether or not global warming is bad should probably go on this thread:
To avoid further distractions on this thread, it is worth noting that the studies mentioned are addressing the question of the cause of recent warming (roughly, over the past century). There are three implications in this:
Three contrarian "talking points" are discounted by these studies:
Gordon's misdirection on "catastrophic" suffers from at least two problems:
Gordon is following the expected contrarian path. Having failed on the 'it's not happening" and "it's not us" arguments, the expected third stage is well under way: "it's not bad". That, too, is an extremely weak position, and few climate scientists exist that hold that position.
I thought the working definition of "catastrophic" for deniers was "something that would force me to pay more tax"
Scaddenp @14 ,
Very droll. And on target. As well as anything causing "change".
Many of them use the same catastrophic ideation about taxation & governments . . . except when the guvmint supplies services to *me*
Bob @12 & 13,
I would prefer to refer to the Skeptical Science definition of catastrophic, that being a the environmental effect of a greater than 4°C temperature rise. We could also ask Dana Nuccitelli (a regular cotributor here) what his definition was when he wrote:
Climate contrarians will often mock 'CAGW' (catastrophic anthropogenic global warming), but the sad reality is that CAGW is looking more and more likely every day.
(Eclectic, is Dana just shouting a slogan here ?)
My original question was what percentage of climate scientists today believe that global warming will be catastrophic ? Given that the IPCC now believes that RCP8.5 has a low likelyhood of occuring, the chances of a greater than 4°C warming along with the prophesied catastrophic effects seem unsupported.
Gordon ~ regarding Dana Nuccitelli, it's all a matter of context.
Easy to see when "catastrophic" is being used as a deflection / strawman that is being shouted (to abort rational thinking).
Catastrophic is defined by the effect (not the absolute temperature e.g. 4 degrees rise). As I am sure you know very well, Earth's surface temperature was above that 4 degC level in the distant past ~ but then there was much more carbon in the biosphere. Nowadays . . . not so much carbon "available", but the biosphere is far less resilient against rapid warming (in large part, thanks to the presence of 8+ Billion humans ~ and many of whom live in poverty already).
Your question about % of scientists "believing" in catastrophic probabilities, is a question that is moot. It is a question that is designed (consciously or otherwise) to deflect thought away from the practicalities of our current situation. Or to deflect from the 97% topic?
In spite of being given a definition of "definition", Gordon @ 16 still fails to provide his definition of "catastrophic".
The quote he has provided, and doubled-down on, says "...the consequences of 4C being potentially catastrophic".
So, we are back to word games. Let's start with the first key word - consequence:
So, clearly it is not the 4C that is catastrophic, - it is (as Eclectic has pointed out), what comes along with the 4C. And Gordon has utterly. completely failed to provide any constructive input on just what those consequences are. He even uses the phrase "..the environmental effect of..." as a substitute for "consequences", without ever actually specifying what those effects would be.
Second important word: potential.
Note definitions 1 and 4. Note the use of "unrealized" and "possible or probable". We are talking here about risk. The "definition" that you have given for "catastrophic" is simply stating that the consequences (of something) are potentially catastrophic.
Your "question", Gordon, is still just as poorly specified as it was in your first comment on this thread,. Since you refuse to say what consequences (or effects) you want people's opinion on, you are asking a meaningless question.
And it is still off-topic for this thread. Go to this one, read it, and pose your questions there. But do not simply triple-down on your useless version.
Also note that Gordon has taken his "definition" quote from the Positives and negatives of global warming post. He linked to the advanced tab in comment 6, and I have now linked to the basic version three times (including this comment).
Gordon has absolutely no justification in ignoring that post, where the consequences are laid out in detail. If he disagrees with those consequences - either that they won't happen, or that they are not bad - then he needs to go to that thread and discuss them there.
If Gordon continues to post off-topic here, there will be consequences. (He can read the Comments Policy to find out what they are.)
I suppose when it comes to catastrophic, lightning could be cited as an example. I've been caught way back in my youth in severe electrical storms high up in the European Alps. I recall one occasion when a multi-channel CG strike hit the large glacier I was descending, some 100 metres away - far too close for comfort. Even the guide I was with was freaked out. Memorable, as readers might well imagine. Nevertheless it would only have been catastrophic if it had instead grounded through either (or both) of us. We ran the few miles to the hut from that moment - it was a long glacier - thereby risking the further catastrophe of both of us dropping down a hidden crevasse simultaneously. I don't know, because we escaped both fates, which catastrophe would have been worse!
To borrow a contrarian meme, "one more nail in the coffin" of Gordon's quest "to find out what percentage of climate scientists believe that global warming will be catastrophic."
The study referenced in the OP is not a survey of "what scientists believe". Skeptical Science has a longer post on the 97% consensus theme. The Cook et al (2013) study is just one of the papers discussed there, and this is how it is described (including a link to the paper itself):
Note that the study looked at the abstracts of published papers. And in a second phase, the study did not ask scientists "what they believed" - they asked authors of papers to rate the papers they had written.
That Gordon confuses reading the literature with "asking what someone believes" tells us more about Gordon than we probably need to know.
If Gordon seriously wants an answer to his "catastrophic" question, along the lines of the study done by Cook et al (2013), there is an obvious solution:
John Mason @ 20:
It sounds to me like you were only caught in a "potentially catastrophic" situation. Since nothing bad actually happened, then obviously it would be pointless in the future to avoid being out on glaciers during lightning events, or running quickly down glaciers with deep crevasses.
(Where is that html sarcasm tag???)
Yes Bob - so it proved. Made the beer taste especially good at - I think because it was a while back - the Braunschweiger Hütte. The next day on the Otztaler Wildspitze was a cracking one, despite most of the party being a tad hungover to start with. High mountains magic. Sorry to take this even further O/T: just revisiting memories!
Polling by Pew Research on American scientists attitudes to the climate issue. (Appears to be all scientists not just climate scientists)
".....And 77 percent of scientists said climate change is a very serious problem......"
www.scientificamerican.com/article/big-gap-between-what-scientists-say-and-americans-think-about-climate-change/
So quite a strong majority of scientists think climate change is a very serious problem.
John Kerry was quoted addressing the British Parliment as saying:
"“If you have five tipping points, and two of them involve the potential of metres, literally multiple metres, double digits of sea level rise, that’s as good a definition of catastrophe as you can achieve.
“And the reality is that that is where we are headed unless we do more about it. Now, why do I have this measure of optimism and of our capacity? Because it is within our capacity."
I thnk in addition to multiple meters of sea level rise there are other potential consequences of climate chnge that would qualify as "catastrophic". Perhaps we could make a list.
I saw a projection of a billion climate refugees or more under some conditions. For me that is way past catastrophic.
How many human deaths in one year , or cumulative, before it counts as catastrophic? Only one if it is a close friend or relative.
What conditions do others here think would count as catastrophic. Perhaps we could find a consensus, Undoubtedly we all have different conditions that have to be met for the problem to be catastrophic.
I remember when the IPCC AR5 came out in 2014 with a list of severe consequences. I wondered at the time if I would live to see sea level rise causing damage, widespread fire storms, heat conditions killing millions etc. I was 56 at the time and thought I would live another 30 years. Now, only 8 years later, we see these problems already happening around the world. I can only imagine what it would be like in 2100 if we do not take as strong action as possible immediately.
In my experience, persons who ask for definations of catastrophic want to minimize the actions we take to try to avoid the already begun catastrophic climate change.
I suspect that "catastrophic" is in the eye of the beholder.
Here in Canada, the western part of the country has been experiencing a lot of forest fires this spring. It is not affecting me in central Canada - but I'm sure the people that have lost homes (or lives) in western Canada consider it to be "catastrophic".
And it is not enough to say "this change is catastrophic", as it depends on the time involved. The boreal forest evolved in response to fire, and it wll eventually all burn mutiple times over. But burning 1% of it each year, so it averages out to be 100 years old, is not the same as burning 10% of it each year so none of it reaches maturity.
Likewise for goal posts such as 2C rise in global temperature. Adapting to this rise and all its consequences over a period of 1000 years is entirely feasible. Adapting to it in 100 years? Not so easy.
I do tend to disagree with Michael's last statement, that definitions of "catastrophic" come from people wanting to minimize actions. People that want to minimize actions tend to use "catastrophic" as a highly mutable goal post, and will not provide a definition. If they provided a definition, they would have to defend it (or run away from any discussion that showed how unreasonable their definition is).
The discussion here regarding the potential position of climate scientists regarding climate change impacts being catastrophic is interesting.
Based on Gordon’s comments it is obvious that the question to be asked of climate scientists is “Does your understanding support the claim that 4 C of warming would be potentially catastrophic?” His alternative question, evading the term potentially’ misleads the discussion into a ‘simplistic but complicated’ debate about the meaning of ‘catastrophic climate change impacts’.
‘How significant’ a catastrophe needs to be to ‘count’ is not a matter of personal opinion. It also is not a matter of political popularity or business popularity and profitability. Applying ethical considerations to the available evidence can establish a general common sense understanding that relates to this matter. Morality and Ethics basically say that preventable harm done is unacceptable, especially if the damage done is irreparable. The construction industry pursuit of ‘zero-injury’ in more advanced nations is a ‘business’ example of the application of this concept. However, political popularity or business popularity and profitability can compromise that fundamental ethics with questionable ethical ‘evaluations that consider the benefits obtained by some people to be worth the harm done, especially of the harm is done to ‘identifiable others’.
Many people unethically consider a catastrophe to only count if it happens to the sub-set of humanity that they have decided to identify with. They are not open to accepting the broad diversity of less harmful and more helpful ways of being human in pursuit of developing sustainable improvements for the future of humanity. Those people can be expected to make up a diversity of arguments attempting to distract from learning about harm done to others. They will even try to diminish harm done to others in the future (a classic ethical test of the merits of things happening later being less important is the question of the ethics of burying a long lasting land mine in a region where it is likely that the mine will only be detonated and harm someone in the distant future).
Using structural engineering or business management as examples of consideration of catastrophe is also helpful. I am a professional civil/structural engineer with an MBA. So these are areas of understanding I am quite familiar with and able to understand in depth.
When engineering things like a structure or surface run-off drainage system there is an important difference between ‘temporary failure of part of the system causing limited and repairable damage’ and a ‘more significant catastrophe affecting more of the system or producing harmful results that are not repairable’. The general engineering rule regarding repairable failure of parts of the system is that the probability of such a localized limited ‘potential catastrophe (because some irreparable harm could occur as a result of the repairable failure) needs to be less than 2%. The potential for a larger or irreparable failure needs to be significantly less than 2%.
For a business, the quarterly or annual lack of performance by a portion of a larger operation is a concern. And a business venture’s sustainability requires the chance of each of those ‘limited catastrophes’ to be small because too many of them happening too often would be a bigger problem. And a larger aspect of the business failing to perform as hoped would need to have a significantly lower probability of occurring.
Sustaining a structure, drainage system, or business requires actions that understandably, based on the evidence, reduce the risk of catastrophic results. Benefiting from harm suffered by others, including avoiding the costs of being less harmful, may be temporarily regionally popular and profitable. But developing sustainable improvements for global humanity requires limitations on the sovereignty (freedom) of ‘all’ portions of the population (business and political) to believe and act as they please.
Relating that understanding to climate change, the probability of ‘catastrophic (irreparable) regional results’, such as needing to relocate or ‘adapt’ any small percentage of already developed human activity, would have to be less than 2%. And the probability of ‘needing to relocate, or revise to adapt, a larger amount of developed human activity’ would need to be a much lower than 2%.
Based on that understanding, open to improvement, the evidence indicates that catastrophic climate change impacts have already occurred at levels of impact below 1.5 C. So, applying that ethical perspective, it is highly likely that a vast majority of climate scientists, perhaps more than 97%, would say that their understanding supports the claim that 4 C of warming would be potentially catastrophic.
Note: There is a very important difference between understanding and opinion. Common sense requires common evidence based ethical understanding. Opinion is free from the restrictions of evidence or ethical consideration.