Climate Change: What’s the Worst Case?

Reposted from Dr. Judith Curry’s Climate Etc.

Posted on August 22, 2019 by curryja |

by Judith Curry

My new manuscript is now available.

A link to my new paper ‘Climate Change: What’s the Worst Case?’ is provided here [worst case paper final (1)]

A few words on the intended audience and motivation for writing this:

First and foremost, this is written for the clients of Climate Forecast Applications Network who are interested in scenarios of future climate change [link]

Second, this paper is written as a contribution to my series of academic papers on the topic of uncertainty in climate science:

Third, the paper is written to inform the public debate on climate change and policy makers.  I am ever hopeful that some sanity can be interjected into all this.

This paper is particularly relevant in light on the preceding post on consensus, and Gavin’s desire for a better way to treat the extreme tails.

Overview of contents

I’m reproducing the Abstract, Introduction and Conclusions in this blog post, I encourage you to read the entire paper.

Abstract. The objective of this paper is to provide a broader framing for how we assess and reason about possible worst-case outcomes for 21st century climate change. A possibilistic approach is proposed as a framework for summarizing our knowledge about projections of 21st century climate outcomes. Different methods for generating and justifying scenarios of future outcomes are described. Consideration of atmospheric emissions/concentration scenarios, equilibrium climate sensitivity, and sea-level rise projections illustrate different types of constraints and uncertainties in assessing worst-case outcomes. A rationale is provided for distinguishing between the conceivable worst case, the possible worst case and the plausible worst case, each of which plays different roles in scientific research versus risk management.


The concern over climate change is not so much about the warming that has occurred over the past century. Rather, the concern is about projections of 21st century climate change based on climate model simulations of human-caused global warming, particularly those driven by the RCP8.5 greenhouse gas concentration scenario.

The Intergovernmental Panel on Climate Change (IPCC) Assessment Reports have focused on assessing a likely range (>66% probability) for projections in response to different emissions concentration pathways. Oppenheimer et al. (2007) contends that the emphasis on consensus in IPCC reports has been on expected outcomes, which then become anchored via numerical estimates in the minds of policy makers. Thus, the tails of the distribution of climate impacts, where experts may disagree on likelihood or where understanding is limited, are often understated in the assessment process, and then exaggerated in public discourse on climate change.

In an influential paper, Weitzman (2009) argued that climate policy should be directed at reducing the risks of worst-case outcomes, not at balancing the most likely values of costs and benefits. Ackerman (2017) has argued that policy should be based on the credible worst-case outcome. Worst-case scenarios of 21st century sea level rise are becoming anchored as outcomes that are driving local adaptation plans (e.g. Katsman et al. 2011). Projections of future extreme weather/climate events driven by the worst-case RCP8.5 scenario are highly influential in the public discourse on climate change (e.g. Wallace-Wells, 2019).

The risk management literature has discussed the need for a broad range of scenarios of future climate outcomes (e.g., Trutnevyte et al. 2016). Reporting the full range of plausible and possible outcomes, even if unlikely, controversial or poorly understood, is essential for scientific assessments for policy making. The challenge is to articulate an appropriately broad range of future scenarios, including worst-case scenarios, while rejecting impossible scenarios.

How to rationally make judgments about the plausibility of extreme scenarios and outcomes remains a topic that has received too little attention. Are all of the ‘worst-case’ climate outcomes described in assessment reports, journal publications and the media, actually plausible? Are some of these outcomes impossible? On the other hand, are there unexplored worst-case scenarios that we have missed, that could turn out to be real outcomes? Are there too many unknowns for us to have confidence that we have credibly identified the worst case? What threshold of plausibility or credibility should be used when assessing these extreme scenarios for policy making and risk management?

This paper explores these questions by integrating climate science with perspectives from the philosophy of science and risk management. The objective is to provide a broader framing of the 21st century climate change problem in context of how we assess and reason about worst-case climate outcomes. A possibilistic framework is articulated for organizing our knowledge about 21st century projections, including how we extend partial positions in identifying plausible worst-case scenarios of 21st climate change. Consideration of atmospheric emissions/concentration scenarios, equilibrium climate sensitivity, and sea-level rise illustrate different types of constraints and uncertainties in assessing worst-case outcomes. This approach provides a rationale for distinguishing between the conceivable worst case, the possible worst case and the plausible worst case, each of which plays different roles in scientific research versus risk management.

2. Possibilistic framework

3. Scenarios of future outcomes

     3.1 Scenario justification

     3.2  Worst-case classification

     3.3  Alternative scenarios

4. Is RCP8.5 plausible?

5. Climate sensitivity

6. Sea level rise

     6.1 Worst-case scenarios

    6.2 Possibility distribution

    6.3 Alternative scenarios   

7. Conclusions

The purpose of generating scenarios of future outcomes is that we should not be too surprised when the future eventually arrives. Projections of 21st century climate change and sea level rise are associated with deep uncertainty and rapidly advancing knowledge frontiers. The objective of this paper has been to articulate a strategy for portraying scientific understanding of the full range of possible scenarios of 21st century climate change and sea level rise in context of a rapidly expanding knowledge base, with a focus on worst-case scenarios.

A classification of future scenarios is presented, based on relative immunity to rejection relative to our current background knowledge and assessments of the knowledge frontier. The logic of partial positions allows for clarifying what we actually know with confidence, versus what is more speculative and uncertain or impossible. To avoid the Alice in Wonderland syndrome of scenarios that include too many implausible assumptions, published worst-case scenarios are assessed using the plausibility criterion of including only one borderline implausible assumption (where experts disagree on plausibility).

The possibilistic framework presented here provides a more nuanced way for articulating our foreknowledge than either by attempting, on the one hand, to construct probabilities of future outcomes, or on the other hand simply by labeling some statements about the future as possible. The possibilistic classification also avoids ignoring scenarios or classifying them as extremely unlikely if they are driven by processes that are poorly understood or not easily quantified.

The concepts of the possibility distribution, worst-case scenarios and partial positions are relevant to decision making under deep uncertainty (e.g. Walker et al. 2016), where precautionary and robust approaches are appropriate. Consideration of worst-case scenarios is an essential feature of precaution. A robust policy is defined as yielding outcomes that are deemed to be satisfactory across a wide range of plausible future outcomes. Robust policy making interfaces well with possibilistic approaches that generate a range of possible futures (e.g. Lempert et al. 2012). Partial positions are of relevance to flexible defense measures in the face of deep uncertainty in future projections (e.g. Oppenheimer and Alley, 2017).

Returning to Ackerman’s (2017) argument that policy should be based on the credible worst-case outcome, the issue then becomes how to judge what is ‘credible.’ It has been argued here that a useful criterion for a plausible (credible) worst-case climate outcome is that at most one borderline implausible assumption – defined as an assumption where experts disagree as to whether or not it is plausible – is included in developing the scenario. Using this criterion, the following summarizes my assessment of the plausible (credible) worst-case climate outcomes, based upon our current background knowledge:

  • The largest rates of warming that are often cited in impact assessment analyses (e.g. 4.5 or 5 oC) rely on climate models being driven by a borderline implausible concentration/emission scenarios (RCP8.5).
  • The IPCC AR5 (2013) likely range of warming at the end of the 21st century has a top-range value of 3.1 oC, if the RCP8.5-derived values are eliminated. Even the more moderate amount of warming of 3.1oC relies on climate models with values of the equilibrium climate sensitivity that are larger than can be defended based on analysis of historical climate change. Further, these rates of warming explicitly assume that the climate of the 21st century will be driven solely by anthropogenic changes to the atmospheric concentration, neglecting 21st century variations in the sun and solar indirect effects, volcanic eruptions, and multi-decadal to millennial scale ocean oscillations. Natural processes have the potential to counteract or amplify the impacts of any manmade warming.
  • Estimates of 21st century sea level rise exceeding 1 m require at least one borderline implausible or very weakly justified assumption. Allowing for one borderline implausible assumption in the sea level rise projection produces high-end estimates of sea level rise of 1.1 to 1.6 m. Higher estimates are produced using multiple borderline implausible or very weakly justified assumptions. The most extreme of the published worst-case scenarios require a cascade of events, each of which are extremely unlikely to borderline impossible based on our current knowledge base. However, given the substantial uncertainties and unknowns surrounding ice sheet dynamics, these scenarios should not be rejected as impossible.

The approach presented here is very different from the practice of the IPCC assessments and their focus on determining a likely range driven by human-caused warming. In climate science there has been a tension between the drive towards consensus to support policy making versus exploratory speculation and research that pushes forward the knowledge frontier (e.g. Curry and Webster, 2013). The possibility analysis presented here integrates both approaches by providing a useful framework for integrating expert speculation and model simulations with more firmly established theory and observations. This approach demonstrates a way of stratifying the current knowledge base that is consistent with deep uncertainty, disagreement among experts and a rapidly evolving knowledge base. Consideration of a more extensive range of future scenarios of climate outcomes can stimulate climate research as well as provide a better foundation for robust decision making under conditions of deep uncertainty.

Publication status

Since I resigned my faculty position, there has been little motivation for me to publish in peer reviewed journals. And I don’t miss the little ‘games’ of the peer review process, not to mention the hostility and nastiness of editors and reviewers who have an agenda.

However, one of my clients wants me to publish more journal articles.  This client particularly encouraged me to publish something related to my Special Report on Sea Level and Climate Change. I submitted a shorter version of this paper, in a more academic style,  for publication in a climate journal.  It was rejected.  Here is my ‘favorite’ comment from one of the reviewers:

“Overall, there is the danger that the paper is used by unscrupulous people to create confusion or to discredit climate or sea-level science. Hence, I suggest that the author reconsiders the essence of its contribution to the scientific debate on climate and sea-level science.”

You get the picture.  I can certainly get some version of this published somewhere, but this review reminded me why I shouldn’t bother with official ‘peer review.’  Publishing my research on Climate Etc.  and as Reports ‘published’ by my company  allows me to write my papers in a longer format, including as many references as I want.  I can also ‘editorialize’ as I deem appropriate.  In summary, I can write what I want, without worrying about the norms and agendas of the ‘establishment.’  Most of my readers want to read MY judgments, rather than something I think I can get past ‘peer reviewers.’

This particular paper is titled as a ‘Working Paper’, in the tradition often used by economists and legal scholars in issuing their reports.  It is publicly available for discussion, and I can revise it when appropriate.  I hope it will stimulate people to actually think about these issues and discuss them.  I look forward to a lively review of this paper.

And finally, it is difficult to see how this paper could be categorized at ‘contrarian.’  It is not even ‘lukewarm.’ It discusses worst-case scenarios, and how to think about their plausibility.  In fact, in one of the threads at WUWT discussing one of my previous ‘worst-case’ posts, commenters thought that this was way too ‘alarmist’ to be posted at WUWT.

Bottom line:  we need to think harder and differently about climate change.  This paper helps provide a framework for stepping beyond the little box that we are currently caught in.

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August 24, 2019 10:14 pm

The worst case occurs when people listen to and act upon the Alarmist and Warmist advice, which is based on imaginary data and theory. This action results in wastage of money, poverty and deprivation of civilisation for the general population of the country while having no effect on the weather..

Crispin in Waterloo
Reply to  nicholas tesdorf
August 25, 2019 5:50 am


You raise a fourth category. Judith Curry provides the “conceivable, the possible and the plausible.” You point out some are using fake or manipulated data to create a fourth category, which could be termed the “inconceivable”. I cannot apply the term “impossible” because Judith is using that to parse the scenarios into things that could happen, as distinct from those that cannot.

The “inconceivable” group are made by creating some projection based on falsified/fabricated, invalidated, or manipulated data (motivated ex post filtering). Any projections based on that are inconceivable because the underlying premises of the argument are unreal. The premises of valid arguments have to be valid.

Tony Heller’s recent post on “the hottest July” identifies NASA’s reliance on positive temperature anomalies in many places for which there are literally no data. They fabricated the data then made claims based upon it. As Willis says, “Bad scientist, no cookie.”

A scenario based on imagined data is not “conceivable” so it lies outside the tails of “extreme” in the land of the “inconceivable.”

Reply to  nicholas tesdorf
August 25, 2019 6:09 am

Humans seem to want to assume trends never end. Many traders lose money on this premise.
Fortunately, nature is not steady. The coming Dalton Minimum, initially to be blamed on Fracking or whatever, will cool us for a while.

I have been following the cloud theory first proposed by Svensmark& Marsh. A good update is It works for me.

Curious George
Reply to  nicholas tesdorf
August 25, 2019 2:36 pm

The worst case is that due to global warming Russia could become habitable. American imperialists want to prevent it from happening. You must understand that the IPCC are just Trump’s lackeys 🙂

Robert Rousseau
Reply to  nicholas tesdorf
August 27, 2019 2:22 pm

The worst case is that when presented with scientific data, some people allow fear, political orientation, and fear of the inevitable loss of their fossil fuel driven fortunes and their conditioned lifestyle to skew their perception. These are not objective opinions we are talking about but 30 years of scientific observation and data. No scientist worth his or her salt deals in imaginary data and we deploy robust statistical methods to verify the accuracy, the repeatability, and the reproducibility of our data. The data does not lie but people with an underlying political or business agenda distort and misrepresent the data. That is called anti climate science propaganda and it is a grave crime against humanity. The Kochs have been doing so for years. I digress.

The same risk tools used by engineers can be applied to assess both the severity and probability of occurrence ( i.e criticality) of climate change outcomes. These risk assessment tools can be modified to more accurately predict climate outcomes. Better yet are some of the algorithms that are being developed. Climate change impacts are actually occurring with greater frequency of occurrence and severity than was previously projected. Changes are coming much faster than we forecast 10-15 years ago. Oceans are already encroaching and displacing people. Rainforest is being hacked down. Carbon emissions went up in 2018 and 2019, so like stupid ignorant beings, we are making things worse, not better. With what we now know a rise of 4° is likely and the consequences are catastrophic. There is not a lot of confidence that the human race could even survive in small numbers with a 4° rise. We are certainly going to bypass 2°. I believe we are currently at 1.8° C. An all out concerted effort by every human being on par withe the worldwide efforts expended in WW2 is needed and I don’t see it happening.

Jack Roth
Reply to  Robert Rousseau
September 3, 2019 8:30 pm

Wow, Robert, what a bunch of bovine excrement. Why don’t you start by doing something? Please give up your car, all plastics, and anything made with or produced with fossil fuels. Go in the Amazon and use a fig leaf to cover yourself, and leave the rest of us alone. I need to spend all this fortune I am making from my vast holdings in fossil fuels, and you’re bumming me out!

J Mac
August 24, 2019 10:40 pm

What’s the worst case?
The planet is slightly warmer.
The planet is a lot ‘greener’, as a direct benefit from the higher atmospheric CO2 level.
Crop yields continue to increase.
Fewer people go hungry worldwide.
Energy is widely available, reliable, and affordable.
Affordable energy continues to improve human sanitation, health, and welfare
Climate change alarmists are openly denigrated for their luddite fantasies.

Reply to  J Mac
August 25, 2019 6:32 am


everyone knows the climate is not static….it’s going to change one way or the other

If someone told you they could convince people warmer is more dangerous….you would never believe them

Reply to  Latitude
August 25, 2019 8:38 am

Worst-case is a sudden turn toward precipitate reglaciation, possibly caused by volcanic eruptions or some other yet-unforeseen event, including solar fluctuations. “Warming” currently experienced is a literal day at the beach compared to everything above Lat. 35 N being under 2 miles of ice.

It’s happened before; sometimes within 35 years I’ve read.

Reply to  J Mac
August 25, 2019 7:47 am

Slightly warmer also results in more green as many areas that are too cold for plants to thrive warm up.
Those places that are already hot will not warm up noticeably due to the fact that water vapor is already saturating the frequencies that CO2 influences.

Reply to  J Mac
August 26, 2019 6:04 am

Demographic trends will play an important role over the next century. Global population will likely peak around 2070. After that, there will be a sharp decline. Yes, some low emitting countries in Africa will ramp, but this will be countered by declines in Europe and Asia. China will lose half its population over the next 100 years, for example.

Also, population aging, currently underway in most countries, will result in reduced emissions. Older populations consume less energy on a per capita basis.

No intervention needed.

John V. Wright
August 24, 2019 10:51 pm

“Overall, there is the danger that the paper is used by unscrupulous people to create confusion or to discredit climate or sea-level science. Hence, I suggest that the author reconsiders the essence of its contribution to the scientific debate on climate and sea-level science.”

Just speechless reading this comment. At the age of 69 I am almost unshockable, but from time to time I hear or read a blatantly racist comment which provokes in me a feeling of shocked incomprehension. This statement from a peer reviewer of Dr Curry s work created that same feeling in me.

This is the scientific equivalent of racism. What the reviewer is saying, basically, is “You are different from us and therefore, outwith any consideration of the scientific content of your paper, we are banning you from having it published”. We are grateful to Dr Curry for her persistence, and courage, in continuing to present her findings in a reasoned, calm and unbiased manner.

But make no mistake about it. This comment is climate science’s Rosa Parkes moment. This comment defines the Groupthink that fired Peter Ridd from James Cooke University. This comment is the unacceptable face of consensus science.

son of mulder
Reply to  John V. Wright
August 25, 2019 12:01 am

That one statement by a reviewer tells me it’s a scam.

Eamon Butler
Reply to  John V. Wright
August 25, 2019 3:40 am

Well said Sir.
What ever happened to, ‘I don’t agree with what you have to say, but I’d die defending your right to say it’


Mark Broderick
Reply to  John V. Wright
August 25, 2019 3:41 am

…aka…”The Gate Keepers” !

Great job Dr. Curry

HD Hoese
Reply to  John V. Wright
August 25, 2019 2:50 pm

I have heard of and read these types of non-scientific comments in more than climate science, even in one rejection for an innocuous historical paper. Long ago I had one rejected for a claimed statistical misuse, percentages were so high statistics weren’t even necessary and the reviewer was wrong. Can’t claim knowing of any this bad though. The validity test is always way down the line, too many want their demands immediately.

August 24, 2019 11:27 pm

There is more than one spectrum of worst-case scenarios. The not implausible rapid descent into the next glaciation deserves mention. Both surely merit preparation.

August 24, 2019 11:31 pm

You must sadly fight the good fight and go through peer review, if only to fight the “consensus” bullying tactic of the activists. If you give up, they win.

Reply to  WR2
August 25, 2019 5:39 am

Once upon a time, Nature and Science were two of the top-ranked scientific journals in the world.

Now, they have published so much nonsense, especially on global warming hysterics, that they have little remaining credibility.

A prime example of this climate nonsense was MBH98, a great steaming pile of horse pucks published in Nature and the centerpiece of the 2001 IPCC Third Assessment Report (TAR),

I say publish on the internet, provide all your calculations in an Excel workbook or other to prove your work, and let everyone take potshots at you. That is real peer review, not the PAL review that has characterized the printed journals like Nature and Science for several decades.

I suggest that:

1. Peer review, aka pal-review, is worthless or less-than-worthless, based on past misconduct by academics.

2. Credentials do not matter either, because so many academics have published blatant alarmist falsehoods about climate and energy.

3. The best objective measure of scientific credibility is one’s predictive track record. It should be noted that the IPCC and fellow-traveller climate alarmists have a PERFECTLY NEGATIVE PREDICTIVE TRACK RECORD – EVERY ONE OF THEIR VERY-SCARY PREDICTIONS OF RUNAWAY GLOBAL WARMING, WILDER WEATHER ETC HAVE FAILED TO MATERIALIZE.
Nobody should believe them.

Crispin in Waterloo
August 25, 2019 6:28 am

Well…no one should believe them until they start making correct predictions borne out by inspectable and respectable measurements.

Reply to  Crispin in Waterloo
August 25, 2019 7:53 am

“… no one should believe them until they start making correct predictions borne out by inspectable and respectable measurements.”

Hi Crispin,

I’ve been studying this subject since 1985, and the blatant falsehoods from the warmist camp just keep on coming – to date, ALL their scary predictions have been wildly incorrect and self-serving. If this scenario involved your plumber, mechanic or electrician, you would have dropped him decades ago and found someone more competent.

I am not willing to wait several more decades for the climate clowns to get it right – they have huge NEGATIVE credibility, and have caused humanity to squander trillions of dollars and many millions of lives. I will never believe them – they are proven liars and fraudsters – that is their life legacy. They will never be credible – not in this lifetime.

Best personal regards, Allan

August 25, 2019 6:52 am

I’m working for a research organization that is involved in climate science that is associated with a major university and what I am seeing is revolting. The standard practice for most researchers in the organization is to search out for evidence of climate change or anything that can be viewed as ecologically damaging. The prime objective is to secure more funding and you’ve never seen so many circular arguments to justify work and findings.

Nearly half of the people in the organization are not researchers. Of these, a large fraction add no value whatsoever. Some support researchers with facilities, budgeting and project management, travel coordination, etc. Others are spin masters, communicators whose jobs involve crafting reports to generate alarm and funding.

The diversity and inclusion office appears to have the role of hiring as many gay people as possible with black lesbians especially desired.

The major grant that I’m working on goes on for about a year. I’m looking to exit upon its expiration. I have run into a number of trapped ethical researchers and many seem to be similarly emasculated. Many of the others work unquestionably in cult like fashion. I’m nudging a couple, ever so slowly and see positive signs, but if I pushed too strongly I’d be labeled a witch and burned at the stake (or be identified as a denier and fired).

Bill Rocks
Reply to  Scissor
August 25, 2019 9:38 am


“The standard practice for most researchers in the organization is to search out for evidence of climate change or anything that can be viewed as ecologically damaging. The prime objective is to secure more funding and you’ve never seen so many circular arguments to justify work and findings.”

You describe corrupt science or perhaps non-science feeding propaganda. Early in my university science education, I was taught some aspects of the philosophy of science, specifically, the error of the Ruling Theory in which investigators select data or facts that confirm their preferred hypothesis. This can be unintentional but you apparently describe an intentional and therefore corrupt organization.

This is very sad and dangerous to liberty and progress. History tells us.

RIP T. C. Chamberlain. What happened to the method of the Multiple Working Hypothesis? Oh, I know, the IPCC charter threw it out the back door.

Reply to  Bill Rocks
August 25, 2019 6:24 pm

Very sad indeed.

ferd berple
Reply to  Scissor
August 25, 2019 10:49 am

with black lesbians especially desired.
Let everyone know you self identify as a black, lesbian, trans.

Anyone that says otherwise is a racist, intolerant, homophobe.

From that point on you are home free

Reply to  ferd berple
August 25, 2019 4:36 pm


Reply to  WR2
August 25, 2019 7:51 am

These peer reviewed journals are the last remnants of a displaced technology.

For awhile, they were needed as one of the few ways to get new science in front of a lot of people.

With the advent of the internet, the need for their existence has gone away. They will continue to fade from existence as more and more people recognize their irrelevance.

Jay Willis
August 25, 2019 1:47 am

“Bottom line: we need to think harder and differently about climate change”…. bottom line, I think we need to think harder and differently about peer review. For instance, I’m a qualified scientist with a PhD and I will undertake a peer review of any of your papers based purely on the basis of the appropriateness of the methods and philosophy of science. Perhaps it is time to set up a pool of likeminded people and do real peer reviews.

Rod Evans
Reply to  Jay Willis
August 25, 2019 2:46 am

Jay, I basically agree with you but in the meantime, I think WUWT does a pretty good job of peer reviewing papers. It is clear the open nature of this site enables those with real knowledge and scientific credentials to reflect on any paper presented and write a critique.
I suspect, that is why the establishments academic community, are so concerned about net based comment, such as happens here.
The desire, particularly of the left wing, to control the dissemination of information is thwarted by net based review. They don’t like that.
The truth will out. No amount of blocking or denying by the pedlars of false paradigms, can avoid open forum review.
Small note of caution, just as consensus has no place in science, volume of views, positive or negative, has no place in establishing truth either.

Crispin in Waterloo
Reply to  Rod Evans
August 25, 2019 6:34 am


One criticism I get from people I direct here is that the “reviews” are too snarky to be taken seriously – that is, the tone of the posts is wearing and in some cases adolescent.

In support of public review, the ISO submits all proposed standards to a 60 day comment period where people (not necessarily novices) can provide input that the technical committees have to address, either themselves or in the working group(s).

The different with climate science is that public review comes after the papers are published, and the editors are refusing to publish the comments received unless they support certain motivated conclusions. The reviewer’s comment above is a perfect example of that. “Lest the paper invalidate my work.”

If the public had a right of reply, as is the case with the ISO, the talk of the “consensus” would quickly dissipate.

The other George
August 25, 2019 1:56 am

There is a worst-case-scenario here. Suppose it turns out to be the case that the ignored knowns dominate climate.
1) Our magnetic field is important for protection from harmful UV. Our magnetic poles are migrating.
2) There is a relation between magnetic connection with the sun and earthquakes and volcanoes. Big volcanoes cause global cooling.
So… scenario 1: Global Warming caused by human emissions raises seas 10 ft over a century. Stop emissions now.
and… scenario 2: Global Cooling caused by nature leads to food riots.
Solution to both: Gen IV Nuclear. (Cannot meltdown, uses older nuke plant waste as fuel.) No CO2 emissions. Provides power to fight the cold if that obtains, or to provide the A/C to survive the warm. Win-win.

Ron Long
Reply to  The other George
August 25, 2019 6:01 am

The Other George, see my post below re next intra-glacial event in our current Ice Age. Now consider the approaching (no idea when) magnetic reversal, wherein we lose our protection against cosmic rays. One side of you will suffer radiation burns and the other side will be frozen, you won’t know which way to turn.

Crispin in Waterloo
Reply to  The other George
August 25, 2019 8:35 am

The other G

Good point. If there are known knowns and they are ignored, how on earth can one describe the atmosphere adequately?

Reply to  Crispin in Waterloo
August 25, 2019 10:14 am

Full of known unknowns and unknown knowns?
Too complex for academics?
(Only engineers have the tools to deal with the most complex issues full of unknown unknowns).

August 25, 2019 2:39 am

What is the worst case scenario? We don’t know. It will be a Black Swan Event. It will take us by surprise. It will happen.

What should we do? We should quit what we are doing with renewable energy. James Hansen thinks it is a scam. Michael Moore thinks it is a scam. It’s a waste of money that keeps us from doing what we should be doing.

Taleb talks about antifragility. It anticipates that Black Swan Events will happen and tries to configure our systems to benefit from them rather than collapse. Is that even possible? I don’t know.

Judith Curry talks about no regrets policies. Those are things that most people would agree are beneficial whether or not the climate warms a lot. Taking the renewable energy money and focusing on no regrets policies would be a much better way to go. Bjorn Lomborg says something similar. We could do a lot of good in the world with a fraction of the money currently being wasted on renewable energy fiascos.

Reply to  commieBob
August 25, 2019 3:16 am

There’s no such thing as a climatic “Black Swan”. Climate doesn’t work that way.

Furthermore, you can’t incorporate Black Swans into planning because, by definition, they fall outside of the probability distribution.

Regarding the probability “tails”, the best we can do is to ensure that our economy is resilient enough to withstand them.

Otherwise, I agree, the worst thing we could do, is to cripple our economy now in a futile effort to prevent the probability tails from happening.

Reply to  David Middleton
August 25, 2019 4:19 am

How about the Yellowstone supervolcano. I bet that would affect the climate.

Reply to  commieBob
August 25, 2019 5:27 am

That’s not a climatic Black Swan.

What is a Black Swan?
A black swan is an unpredictable event that is beyond what is normally expected of a situation and has potentially severe consequences. Black swan events are characterized by their extreme rarity, their severe impact, and the practice of explaining widespread failure to predict them as simple folly in hindsight.

The closest thing to a climatic black swan is the utter failure of the Earth’s atmosphere to warm as much, or as quickly, as forecasted by the climate models.

Yellowstone is a known geophysical hazard. We have a pretty good idea of the worst case eruption scenario. We can’t predict when the next ultra-plinian eruption will occur or exactly what the effects will be. We will probably have some advanced warning of a major eruption because it is closely monitored and we know the effects will be devastating. A sudden ultra-plinian eruption from an extinct or previously unrecognized volcano would be a geophysical Black Swan.

Reply to  David Middleton
August 25, 2019 10:30 am

David Middleton wrote:
“The closest thing to a climatic black swan is the utter failure of the Earth’s atmosphere to warm as much, or as quickly, as forecasted by the climate models.”

How about this scenario:
Our elected climate clowns cripple our energy systems with intermittent wind and solar power to “fight global warming” .AND. Earth starts to COOL due to natural causes.

I predicted this “highly unlikely” combined Black Swan event in 2002 and repeated my warning several times since then.

In 2002 I predicted that global cooling would commence by ~2020-2030. For the past few years I’ve been saying closer to 2020. Theodor Landscheidt predicted global cooling in a paper published in 2003, with the coldest period occurring about 2030. Both cooling predictions were based on low solar activity.

As I recall, there was a very late, cold Spring and ~1-month late crop planting in the Midwest last year , but excellent warm summer weather made up for that. This year, cold wet weather in the Midwest reportedly caused ~30% of the USA corn crop to not get planted – the ground was too wet for equipment.

I wonder whether the last two years of significantly late planting in the North American grain belt are early signs of cooling. Hope not.

I’ve always said I’d rather be wrong about imminent moderate global cooling. Humanity suffers greatly during cooling periods.

Reply to  David Middleton
August 25, 2019 11:22 am


The PEGG, November 2002, reprinted in edited form at their request by several other professional journals, the Globe and Mail and La Presse in translation
By Sallie Baliunas, Tim Patterson and Allan MacRae
“Climate science does not support the theory of catastrophic human-made global warming – the alleged warming crisis does not exist.”
“The ultimate agenda of pro-Kyoto advocates is to eliminate fossil fuels, but this would result in a catastrophic shortfall in global energy supply – the wasteful, inefficient energy solutions proposed by Kyoto advocates simply cannot replace fossil fuels.”

Calgary Herald, September 1, 2002
By Allan M.R. MacRae
“If [as we believe] solar activity is the main driver of surface temperature rather than CO2, we should begin the next cooling period by 2020 to 2030.”

By Theodor Landscheidt, May 1, 2003
“Analysis of the sun’s varying activity in the last two millennia indicates that contrary to the IPCC’s speculation about man-made global warming as high as 5.8° C within the next hundred years, a long period of cool climate with its coldest phase around 2030 is to be expected.”

that the UK’s approach to alleged manmade global warming and green energy was ill-founded and would greatly increase energy costs, with no benefit to the environment.

By Allan MacRae, October 31, 2013
“So here is my real concern:
IF the Sun does indeed drive temperature, as I suspect, Baroness Verma, then you and your colleagues on both sides of the House may have brewed the perfect storm.
You are claiming that global cooling will NOT happen, AND you have crippled your energy systems with excessive reliance on ineffective grid-connected “green energy” schemes.
I suggest that global cooling probably WILL happen within the next decade or sooner, and Britain will get colder.
I also suggest that the IPCC and the Met Office have NO track record of successful prediction (or “projection”) of global temperature and thus have no scientific credibility.
I suggest that Winter deaths will increase in the UK as cooling progresses.
I suggest that Excess Winter Mortality, the British rate of which is about double the rate in the Scandinavian countries, should provide an estimate of this unfolding tragedy.
As always in these matters, I hope to be wrong. These are not numbers, they are real people, who “loved and were loved”.”

by Allan M.R. MacRae, B.A.Sc., M.Eng., P.Eng., Jun 15, 2019
This paper summarizes and expands upon my technical papers back to 2002 inclusive.

Reply to  David Middleton
August 25, 2019 12:37 pm

In a recent thread you said the next few months Allan, what, is your crystal ball clouding over a bit?

Reply to  commieBob
August 25, 2019 1:35 pm


Your comments are false, imbecilic, and anonymous – just more “drive-by shootings” from the warmist camp. I will bet you have no significant education, intellect or accomplishments.

Kindly provide everyone with your real name and location, your educational background and your career achievements, if any. If you have none, bugger off.

Reply to  David Middleton
August 25, 2019 5:24 am

Lao Zi (Lao Tse) was writing about antifragility more than 2000 years ago. link

Reply to  commieBob
August 25, 2019 5:31 am

Sun Tzu was writing about not losing wars back then too. Logic doesn’t really change over time.

Resiliency is always the best course of action.

Alasdair Fairbairn
August 25, 2019 2:42 am

The worst case scenario lies on the route to the Green New Deal.

Rod Evans
Reply to  Alasdair Fairbairn
August 25, 2019 4:55 am

The worst case scenario is, The Green New Deal.!!

August 25, 2019 2:47 am

Thank you for the paper, I have downloaded it. As I see it the main difficulty with it is it takes a heavy mental commitment to fully read and understand. This means it is wasted on most in the political spectrum – they will not make the necessary effort, and there is no way we can make them do it. Human beings are naturally lazy; well at least I am.

Mark Broderick
August 25, 2019 3:32 am

As far as I am concerned, the “Worst-case scenarios” would be:

1) Return of the Little Ice Age.
2) Start of the next Glaciation.

Why are these not included ? We know from the past that temperatures do not just continually go up !
Compared to “scenarios” of 20 m sea level rise, I find these more likely…

Reply to  Mark Broderick
August 26, 2019 4:15 pm

Mark Broderick, I agree. True worst-case scenarios should include possibilities of extreme low as well as extreme high global average surface temperature changes over the next 100 years or more. It is my understanding that climate model outputs have been constrained to only include global average surface temperature projections within an “acceptable range”, which generally means on the high side for trends, while runs that produce low projections are unscientifically discarded as outside the “acceptable range”. This approach is confirmation bias at its worst and more like pure speculation to secure grant money.

Ron Long
August 25, 2019 4:08 am

It’s good that you try to communicate to the Green New Deal mob as well as all others in between, Dr. Judith. However, there is a real worst case scenario, and it is this: the earth is currently in an Ice Age, and we are near the end of one of the inter-glacial phases, and this ends and the earth plunges into the next intra-glacial phase.

Writings about the plunge into the LIA describe a very cold winter, the summer without summer, and the following winter of the LIA in full bloom, with the River Thames frozen down to the saltwater line. Are we ready to believe that us humans are capable of putting enough CO2 into the atmosphere to stop the next intra-glacial phase? The Green New Deal mob is about the attempt to spread socialism everywhere, and CAGW is one of their useful tools. Since you can’t fix stupid, I’m on my way to play golf with friends, which is two strikes already against me today.

Samuel C Cogar
August 25, 2019 4:54 am


The concern over climate change is not so much about the warming that has occurred over the past century. Rather, the concern is about projections of 21st century climate change based on climate model simulations of human-caused global warming, particularly those driven by the RCP8.5 greenhouse gas concentration scenario.

Should not the 21st century prediction(s) of the 2nd coming of Jesus Christ be a greater worldly concern ……. than computer generated climate modeling simulations of human-caused global warming?

If not, ….. why not?

Two peas from the same pod should be judge equally.

August 25, 2019 5:19 am

Warmists desperately want (and perhaps need) the worst-case scenario to be true. They would be devastated if fresh science said “it’s really not going to be bad — get on with your life”.

Reply to  BallBounces
August 25, 2019 5:32 am

That’s why they’re rooting for a recession.

Mark Broderick
August 25, 2019 6:08 am
John Peter
August 25, 2019 6:12 am

I would like to see a paper which picks up all the claims made to justify ‘Climate Emergency’, research the past original records, be it news papers, scientific papers or other records to find if similar or worse episodes have happened in the past. I mean going back to original records before ‘homogenization’. I will bet my bottom dollar that there is nothing new under the sun. I always think what would John Steinbeck think if he saw NOAA and GISS temperature records of the thirties in their current temperature statistics.

August 25, 2019 6:12 am

There is certainly significant value in a “possibilistic” analysis of worst case scenarios, if only to make sure that poorly understood phenomena are not simply dismissed out of hand as Judith describes.

However, since future climate performance is effectively unknowable – which of course the climate alarmists will never admit – from a practical perspective, all we can do as humans is to develop contingency plans. To go through the process of considering options. If warming of X degrees occurs, and sea level rise of Y meters results, then (A) qualify and quantify the impacts and (B) devise actions to mitigate the negative impacts, and (C) devise actions to take advantage of the positive impacts.

Note that the climate alarmists never ever ever consider (C).

There is no room for, or excuse for mindless panic or propaganda in this rational and logical process.

August 25, 2019 6:19 am

To put it more simply, every “study” warning of a dire future is based on computer projections from RCP8.5, but projections based on measurements of current global temperature and sea level trends are squarely in the RCP2.6 range.

RCP8.5 temperature: 2.6 to 4.8 °C
RCP2.6 temperature: 0.3 to 1.7 °C
Measured temperature trend (last 40 years): 1.3 °C

RCP8.5 sea level rise: 0.45 to 0.82 meters
RCP2.6 sea level rise: 0.26 to 0.55 meters
Measured sea level trend: 0.31 meters

RCP8.5 is the “do nothing” scenario. Despite all the hue and cry by our governing elites, on a global scale we are essentially doing nothing to mitigate CO₂ emissions.

RCP2.6 is the scenario where every country in the world, in a united effort, aggressively reduces CO₂ emissions; an implausible proposition. Despite global emission-reduction slothfulness, temperature and sea level trends indicate we are on track for this rather benign future.

Tom Abbott
Reply to  stinkerp
August 25, 2019 9:10 am

Thanks for putting things in perspective, stinkerp.

To repeat: “RCP2.6 temperature: 0.3 to 1.7 °C
Measured temperature trend (last 40 years): 1.3 °C”

This is what is being observed. This is not a problem for the Earth’s weather and climate. Just look around you (and don’t pay attention to the scaremongers claiming thunderstorms are evidence of CAGW). All the scary CAGW scenarios are based on the worst-case-possible climate models that have no connection with reality, as should be obvious.

There is no evidence that the Earth has ever experienced a runaway greenhouse even though atmospheric CO2 levels have been 100 times higher in the past than they are now. No runaway greenhouse happened in the past, based on CO2, and it won’t happen in the future, based on CO2.

Tom Abbott
Reply to  Tom Abbott
August 25, 2019 2:46 pm

to quote myself: “There is no evidence that the Earth has ever experienced a runaway greenhouse even though atmospheric CO2 levels have been 100 times higher in the past than they are now.”

I meant to say 10 times, not 100 times.

Current levels of CO2 are about 415ppm in the atmosphere and it has been up to 7,000ppm in the past while causing no discernable ill effects on the Earth’s climate or weather.

August 25, 2019 6:48 am

Hi Judith,

I do not see credible evidence that climate sensitivity (ECS or TCS) is greater than about 1C/(2xCO2).

I suggest that ~1C/(2xCO2) is the Upper Bound of ECS and TCS and the actual range of values is probably much less, closer to 0 than 1C/doubling.

Here is why:


1. In 2008 I made the following major observations in this paper:
“Carbon Dioxide Is Not The Primary Cause Of Global Warming”, January 2008

a. The velocity of changes of atmospheric CO2 [dCO2/dt] varies ~contemporaneously with changes in global temperature.

b. Therefore the integral of dCO2/dt, changes in atmospheric CO2, lag changes in global atmospheric temperature by ~9 months.

The above figures employ Mauna Loa (mlo) CO2 data. Similar results were observed using Global CO2 data, as in MacRae 2008. The impact of major (century-scale) volcanoes is apparent. The 12-month delta in CO2 is used to allow for the “seasonal sawtooth” in the Keeling Curve.

2. In 2013, a similar observation was made by Humlum, Stordahl and Solheim – that atmospheric CO2 changes lag global sea surface and air temperature changes by 9-12 months.
“The phase relation between atmospheric carbon dioxide and global temperature”
Global and Planetary Change, Volume 100, January 2013

a. Changes in global atmospheric CO2 are lagging 11–12 months behind changes in global sea surface temperature.
b. Changes in global atmospheric CO2 are lagging 9.5–10 months behind changes in global air surface temperature.
c. Changes in global atmospheric CO2 are lagging about 9 months behind changes in global lower troposphere temperature.

3. Scientists who support the catastrophic human-made global warming (CAGW) hypothesis say that based on physics at the molecular scale, they KNOW that CO2 is a greenhouse gas and more CO2 will cause warming.

What are the scale-up effects?

Earth is not molecular-scale, and there are complex CO2 interactions between the oceans, the land, the biosphere and the atmosphere.

Warming tropical oceanic temperatures cause evaporation of seawater, tropical water vapour increases (and water vapour is a much more potent greenhouse gas than CO2), equatorial warming follows, that warming then extends to the rest of the planet, and atmospheric CO2 increases.

In summary, tropical sea surface temperatures increase, global temperatures increase, and atmospheric CO2 increases, in that order.

Atmospheric CO2 is increasing, and the conventional view is that this CO2 increase is human-made, caused by fossil fuel combustion, deforestation, etc. While this is scientifically important, it is not necessary to debate this point in order to disprove global warming alarmism.

Scientists including Salby, Berry and Harde have hypothesized that the increase in atmospheric CO2 to more than 400 ppm is largely natural and not mostly human-made. While my 2008 observations support this hypothesis, I have considered this question for ~11 years, and am still agnostic on the conclusion.
The Keeling Curve, Scripps Institution of Oceanography
Address to the Sydney Institute, Murry Salby, 2011–9I
“Human CO2 Has Little Effect on Atmospheric CO2”, Edwin Berry, 2019
“What Humans Contribute to Atmospheric CO2: Comparison of Carbon Cycle Models with Observation”, Hermann Harde, Earth Sciences, June 2019


Temperature drives atmospheric CO2 much more than CO2 drives temperature. Climate is NOT highly sensitive to increasing CO2. Increasing CO2 will NOT cause dangerous global warming.

Regardless of the cause, the increase in atmospheric CO2 significantly increases crop yields, and is strongly beneficial to humanity and the environment.

August 25, 2019 6:48 am

The question isn’t whether the climate will change but what we humans can do or are doing that has any effect on that change. Very important to separate “changing climate” from “human climate effects” in this discussion. Otherwise, the worst case will be perceived as caused by humanity.

At this point it appears that the actual human climate effect may be minimal and certainly uncertain.

John Shotsky
August 25, 2019 7:25 am

Studies of the past have shows us that CO2 rises AFTER temperature rises. Co2 does not cause warming. So the entire emissions scenario is simply a non-issue. Emissions of particulate matter do count – but not Co2. The worst case scenario is when earth sinks into another ice age cycle, as it most assuredly will do. These interglacial periods are short compared to the glacial cycles that end them.
The biggest problem I see is that we are not preparing for the ice age that is coming. Just imagine a mile of ice where New York City now stands. That is what it was like just about 12,000 years ago, an eyeblink in geological time. People will not be able to live where the ice takes over. That will cause mass migrations, to places that cannot support the migrants. Crops will fail. People will die.
THAT is the worst case. Not that it may warm a bit more before the ice comes back.

Gary Pearse
August 25, 2019 7:31 am

“… rapidly evolving knowledge base …” Judith I suggest dropping this. It doesn’t inform your assessments of plausibility, etc. Indeed, the basic nitty gritty is that of Charney and even Arhenius of over a century ago. The latter even opined that it would be beneficial which I don’t see you covering (The Great Greening toward a Garden of Eden Earth).

No other science in history has had anywhere near so much money thrown at it and we still are getting the same old hype. The reason, of course, is that a high school drop out Canadian Communist (Maurice Strong) essentially gave marching orders to explore the Anthro driven climate in isolation from natural variability. He created the Stockholm Conference, Kyoto, UNFCC and the IPCC – quite a resume, makes good reading! He basically defined both the problem and its outcome unless we give the UN/elites sovereignty over our daily lives.

Projections over 40yrs ‘show’ 300% greater warming than is shown by observations and even ‘observations’ has been grossly tampered with to exaggerate the rate.This certainly has to be one of the pillars of the ‘knowledge base’.

That the consensus and IPCC, in light of the huge overestimate of warming and a 2-decade Pause in the 40yr period, abandoned the 2C warming above 1950 by 2100, pushed the starting gate back to 1850 and made the threshold 1.5C shows they don’t think the rate is really going to change. Translation: now dangerous warming from 1950 to 2100 is +O.7C, the same rate as the previous century of warming!!

If we believe that other cycles of glaciation lie, ahead (perhaps the most probable future of all), shouldn’t we evaluate forestalling this as a ‘precautionary’ consideration? How about this for a rational, even logical, policy: let the CO2 have its way until 2050 and allow the climate to warm and finally satisfy ourselves that CO2 is even a principal warming component and evaluate the greening and status of crops and have an independent, non climate scientist accounting group do a cost benefit analysis.

The above experiment is already under way! And this is what the climate alarmists are so hysterical about. They suspect the truth but don’t want to go there. The China, India, other Asia, Africa etc. are dwarfing the CO2 emissions of the developed West. Judith all your efforts on risk and probability are indeed just academic now. The CO2 emissions scheduling is now far worse than the IPCC projected as ‘business as usual’ . Were I you, I’d assume CO2 is actually going to be double the worst case and set myself to finally discovering the real magnitude of CO2’s effect. Please believe I’m trying to be helpful.

Reply to  Gary Pearse
August 26, 2019 6:54 am

A worthwhile post, thank you Gary.

One further point is that as fossil fuel combustion strongly accelerated after ~1940, Earth COOLED until 1977.

This was a full-Earth-scale test, without the huge scale-up errors that are involved in moving from molecular scale to Earth scale.

Based on this information we don’t even know if climate sensitivity is positive or negative, especially IF we employ the IPCC’s .FALSE. assumption that most or all of global temperature change is caused by changes in atmospheric CO2.

Why .FALSE.? Because we also know that atmospheric CO2 changes LAG atmospheric temperature changes at all measured time scales, from ~9 months in the modern data record to ~~800 years in the ice core record and most of us will agree that the future cannot cause the past (it’s a bit more complicated than this, but not much).

A safe, reasonable assumption is that actual climate sensitivity, if it exists at all in significance, is less than 1C/(2xCO2) and there is no real global warming or wilder weather crisis.

Jimmie Dollard
Reply to  Gary Pearse
August 28, 2019 9:30 am

But, we have only 12 years to act! Only 12 years to impose our global government before it is obvious that fossil fuels are not causing CAGW.

August 25, 2019 8:16 am

How can we expect to carry on any meaningful research and debate and develop solutions to any actual problems when the people running government agencies such as NASA hold FUNERALS for GLACIERS?

Reply to  TEWS_Pilot
August 25, 2019 11:49 am

My understanding is that Ok, the glacier in question, is about 700 years old.
So, some 800 years ago – roughly 1215 AD, the Year the Great Charter [Magna Carta] was sealed – it didn’t exist.
Presumably, the climate [at least locally] was warmer then.
Ok has since flickered in and out of existence.
Oh dear. What a pity.


August 25, 2019 8:38 am

Newton, Einstein, Watson and Crick were not peer reviewed …according to Joanne Nova…“Peer review by anonymous unpaid reviewers is not a part of the Scientific Method.”

Reply to  TEWS_Pilot
August 26, 2019 3:38 am

Excellent point, thank you!

Besides, in climate science, it’s PAL review, not peer review.

This is especially true in dendrochronology (wood, hokey sticks, etc.).

Walt D.
August 25, 2019 8:57 am

“Worst case”?
You have to buy the unproven hypothesis that small increases in average temperatures will produce catastrophic effects on the climate.
A series of very cold winters would be much more catastrophic.

John F. Hultquist
August 25, 2019 9:16 am

In summary, I can write what I want, . . .

Thank you for doing so.

Tom Abbott
August 25, 2019 9:32 am

From the article: “Natural processes have the potential to counteract or amplify the impacts of any manmade warming.”

This is one of the more important points made.

Natural processes could offset all of the heat CO2 might add to the Earth’s atmosphere. This is not in dispute. The reason it is not in dispute is because climate science has a long way to go to establish the basic parameters, like how much extra heat does CO2 contribute to the Earth’s atmosphere, and is this offset by other mechanisms in the Earth’s atmosphere. The answers to these questions are not yet known.

From history, we know of no instance where CO2 has amplified the impact of the Earth’s climate, which makes this possibility very unlikely.

This pretty much rules out CO2 detectably amplifying climate dynamics, but the possiblity that CO2 adds no net heat to the Earth’s atmosphere has *not* been ruled out, and must be ruled out if humanity is to spend itself into bankruptcy trying to reduce our CO2 output.

We can’t rule out the “no net heat added by CO2” speculation, so what we should take from this is the climate science is definitely not settled, and observations of the real world should lead us to believe that CO2 is beneficial and poses no danger to humanity at all.

The problem is there is a LOT of money being spent to make CO2 appear to be a danger to humanity.

But, as noted, the Scaremongers don’t really have any evidence to back up their claims, they can’t even declare the “no net heat” speculation as being settled, much less the rest of the science, and actual observations of the Earth’s weather don’t correspond with their dire claims and predictions.

August 25, 2019 10:11 am

This question of “what’s the worst that can happen”, is a bit like asking “what’s the worst that can happen when starting a car” … Ok, once it started WWI (if the car carrying the bloke who was shot hadn’t started there would be no WWI).

There are many ways the climate could change, and almost none of them are being covered by the IPCC. So, it’s almost a meaningless question. Moreover, when you understand the climate,, the chances of warming of even 3C is so diminishingly small that it’s pointless discussing it, whereas the chances of a rapid and relatively large cooling event is quite significant (1 in 20 in the next 100 years?). However, within that framework of 100 years there are many other potential factors such as volcanoes, asteroids, or some organism that destroys plants altering climate.

But even the concept of “climate change” is bullshit, because change occurs at all levels and all scales. So it can be changing on one way in one place and another in another. And one may be catastrophic to those in the area and totally beneficial to another group.

The issue is so complex, that a reasonable person would NEVER EVER just think about a single minor change from CO2.

August 25, 2019 11:24 am

Curry has progressed from climate scientist to political activist… a bold step and one honestly taken, but I don’t think there’s any going back to pure science after that.

Curry has always been an honest an refreshing change from people who always have set their political stance before their science.

August 25, 2019 11:48 am

One obvious law for making erroneous scientific projections (especially about the future) that cost the population $Trillions should be codified:

If a science group (leader and all signatories) makes projections that are in error by 100%, that group shall be prosecuted and monetary penalties will be paid by all the individuals involved and by the Institutions where the individuals did their work. Fines shall be equal to the monetary losses incurred by taxpayers not to exceed $100 Trillion (so as not to be considered I reasonable), and incarceration periods shall be equal to twice the period cited in prognostications. All Academic Degrees shall be revoked. And just like School Loans, there will be no bankruptcy protections.

There should be no dissenters to this rule, since the science is so solid…what with nearly unanimous consensus in all of simple, low complexity sciences related to Climate.

Those (hundreds of) science groups (leaders plus all signatories) who have already made prognostications with > 100% errors (like sea levels up to Manhattan’s shoreline streets by 2012) shall no longer speak in public on the subject of Climate (e.g. Gore; Mann). Long jail sentences shall apply. Press releases in support of “100% error studies” must mention that the authors are incarcerated and their Academic credentials were revoked, and that the authors are no longer scientists.

Roger Knights
Reply to  DocSiders
August 25, 2019 7:54 pm

If there is a bad failure of warmist predictions, the MSM and Greens will be considerably discredited for 50 years. And green politicians who have misspent on Unreliables, will look like the fools they are. The Internet won’t forget; their proclamations will come back to haunt them.

Roger Knights
Reply to  Roger Knights
August 25, 2019 8:46 pm

PS: Greens and the MSM will never regain their former authority. Nor will science. The endorsement of alarmism by nearly all the world’s scientific societies will taint them, and organized science, forever. Contrarians will always have backing from that flub to respond to any of science’s diktats with, “Don’t talk down to me, you jerks. You’re not going to baffle me with your BS anymore.” Scientists will have proved their ingrained and inbred unwisdom and shallowness to the world for all time.

August 25, 2019 1:29 pm

What gets me is that all future scenarios avoid questioning their assumptions as to emissions over the next 80 years. The idea that gas powered vehicles will predominate beyond 2025 I find incredibly
nonsensical. Electric cars will predominate because they are a SUPERIOR technology, not because they don’t burn fossil fuel (directly). And the electricity that powers us all will certainly be generated by nuclear molten salt small modular reactors – they will prevail on the basis of just about every characteristic they possess : safety, flexibility, economics, speed of construction, ability to load follow, tiny geographic footprint, ability to be located virtually anywhere. Thus making estimates of the future without embracing these future technologies makes as much sense as estimates of the future made in 1960 that did not anticipate the vast advances in computer technology .

Rod Evans
Reply to  ColMosby
August 25, 2019 2:28 pm

ColMosby, you make the not unreasonable assumption that logic will play a part in future energy decisions. All evidence so far suggests that is not likely to be the case.
Because something is true/valid does not make it automatically adopted as ideal policy. The Green socialists don’t play by rational rules, they have a religious dogma driving them.

Roger Knights
Reply to  ColMosby
August 26, 2019 1:38 am

“they [I assumed below you were talking about BEVs, not reactors] will prevail on the basis of just about every characteristic they possess”

Not range—charging stations are rare, and charging takes time.
Not initial cost.
Not operating cost, or not by as much, if the price of electricity necessarily skyrockets. Only if, as you predict in the face of intense anti-nuclear forces, “the electricity that powers us all will certainly be generated by nuclear molten salt small modular reactors”
Not safety if a BEV is trapped by a snowstorm—the heating will run out much sooner than on an ICE. Or if a BEV gets caught in a traffic jam due to an evacuation. Its power will run out just from keeping the battery at the correct temperature and tha A/C or heating running. Aft a dozen BEVs go dead in such a jam, the delay will increase (because some BEVs, like Teslas, can’t be towed, but must be carried off on flat-bed trucks, and because there are no roadside refills for any BEVs), causing a cascade of further dead BEVs.

Oh—you were talking about the advantages of molten salt reactors,, not BEVs. But their superiority is a bug, not a feature, to our elites.

Jimmie Dollard
Reply to  ColMosby
August 28, 2019 10:15 am

Very well said. I think this is a good summary of the do nothing scenario. The most common error in making forecast is “Assuming everything else remains the same.” Anyone who looks back over the past few decades and thinks the next few decades will be the same as now should not make forecast. Nuclear power has proven reliable and safe for 60 years and improved versions are almost a certain in the next couple of decades unless we fall for the ACGW fraud and destroy modern civilization.

Not Chicken Little
August 25, 2019 4:23 pm

The worst case is that governments all over the world run by people who cannot think and reason logically or scientifically, who do not base their actions on evidence, fall for the scam that is “Man-made catastrophic climate change” and spend trillions of dollars and other currencies extracted by force from their citizens, to combat a problem that is not a problem, and that cannot be stopped or affected by Man’s efforts one way or the other. The worst case is the scammers will get rich and everyone else will get poorer, and stupider…

Oh wait, this is already happening…

August 25, 2019 4:47 pm

It’s prudent to prepare for plausible worst-case scenarios, in order not to be surprised by them. I believe civil engineers have to build this in to planning for such things as bridges and buildings. Storm Sandy was not a particularly bad storm, and hurricanes have been less than predicted by alarmists, not more, yet the NYC area was poorly prepared. And this is obviously a rich urban area in a rich country. There is much that could be done.

Reply to  Lloyd W. Robertson
August 25, 2019 4:54 pm

Perhaps the elites in charge are as unconcerned as the former “Hypocrite-in-Chief” Obamas, who just bought a $15 MILLION SEASIDE Mansion.

August 25, 2019 5:04 pm
People should read this to understand what the limitations of the peer review proceess are.
Here we have a dishonest author. In climate science, we also have dishonest/incompetent reviewers.

August 25, 2019 8:44 pm

The above is a great read.
Thanks to Dr Curry and friends, I’m vindicated for quitting science in mid-career in 1984. (age 49).
Years ago, taking time, I analysed comments that showed Dr Curry to be the most respected of climate scientists by her peers. Now many people know that. I can vouch for the wasteful and even evil side of science as in the above comments.

In my case, I was ousted by a bully in 1964 (for being a “tall poppy”, and my career has been shredded ever since, always behind my back – I never heard a word of what everybody else “knew”. Feeling hatred, briefly, in 1964, I vowed never to waste time on recriminations – or scientific publications – and never have. I have never looked back (until now). But in recent years, with important results in ecology/global conservation/extinctions to report, I’m now caught, unable to do that. I’m desperate to find an honest broker (and there will be many contributing friends above) to accept my software and databases, etc, expecting that they will be able to deliver them to where they can be promoted.

Please see background information at This describes how, by standardising species names for all [2m] described species, Linnaean taxonomy becomes totally available (along with abundant vernacular names in many languages) to enable grassroots conservation groups to manage environmental data by using biodiversity classification as an index. Making this “simple” eg for school use, was the challenge. This achieved, it still defeats suspicious professionals, (especially when they have been warned to keep away, my guess, as above).

BioLists “does” all necessary taxonomy, making possible grassroots ecology globally. The aim, from 1984, was global conservation, seen, by a few, to be potentially as serious a crisis then as it more obviously is now. I claim BioLists to be the only current conservation initiative aiming to bend human behaviour in a sustainable direction. It has the potential to defeat the sixth mass extinction event simply [the crux] by people widely gaining use of common names for their local biodiversty and so learning to observe and learn from nature. For years, I’ve understood that this would have to await a biodiversity crisis to trigger it to go viral fast enough to side-step unseeing, unthinking biologists. That, one and only, time is now.

BioLists, my life’s work, is now stranded in the ever-more bleak scientific wilderness. Within day’s, I desperately need to transfer ownership of BioLists to someone who will then find a suitable agency to promote it. I just need basic details (and some assurance) to effect the transfer. I will send databases, and further notes, to the same address. Please help. My CV and list of publications is at
With Thanks

Al Miller
August 26, 2019 1:53 pm

Until we get to a point where the sane voices where people Dr. Curry can be heard the overall effect on the status of “science” and sadly scientists, in my opinion, is drastically downgraded.
Hysteria and fear mongering will never win the day.
Science is something entirely different from the current practice in “Climate Science”, and people recognize that at some level regardless of vocation or education. I’m no scientist, however I started as a true believer of radical thought. Reading and researching facts made me question and ultimately reject outright the climate claims and CO2 lies being perpetrated. Of course the alarmists are banking on the fact that most are too busy trying to make ends meet to fight back or even do the time consuming research required to see through the thin veil of falsehoods.

Bob Weber
September 2, 2019 11:59 am

What’s the worst case? Being blind-sided, side-swiped by what you didn’t see coming.

Climate extremes & CO2 follow solar extremes.

The UN warns on “warming”, yet cooling has started without recognition, or of real risks.

The pdf tails for climate risk are defined by solar extremes and duration.

Long lower solar activity means a cooler & more arid climate, w/lower annual CO2.

Long higher solar activity means a warmer & wetter climate, w/higher annual CO2.

We now have a reliable empirically-derived long-term sun-climate prediction ability.

Bob Weber
Reply to  Bob Weber
September 2, 2019 12:01 pm

oops it looks like I goofed up a tag

Bob Weber
September 2, 2019 12:15 pm


The UN warns on “warming”, yet cooling has started without recognition, or of real risks.

The pdf tails for climate risk are defined by solar extremes and duration.

Dr. Curry’s article motivated me to work through to the endgame, thanx.

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