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There are genuine climate alarmists, but they're not in the same league as deniers

Posted on 9 July 2018 by dana1981

Those who debunk climate change misinformation often face a dilemma. We’re flooded with such a constant deluge of climate myths, where should we focus our efforts? Climate misinformation is propagated via congressional climate hearings, conservative media outlets, denial blogs, and even from some genuine climate alarmists. 

Specifically, there has recently been a debate as to whether Skeptical Science– a website with a database of climate myths and scientific debunkings, to which I’m a primary contributor – would be more useful and effective if it called out misinformation from ‘alarmists,’ and if it eliminated or revised its Climate Misinformers page.

Richard Betts?@richardabetts

I describe the SkS lists as political because their 'misinformer' lists don't include those on the 'climate action' side who actively deny science & espouse conspiracy ideation

There is some validity to these critiques, and in response, Skeptical Science is renaming the page ‘Climate misinformation by source.’ But the site is run entirely by a team of international volunteers, and as such, opportunity costs must be considered. Time devoted to refuting alarmists is time not devoted to debunking the constant deluge of climate denial.

Unlike deniers, climate alarmists are not influential

Climate deniers are obviously incredibly influential. Despite their lack of supporting evidence or facts, not only do 28% of Americans continue to believe that global warming is natural and 14% that it’s not even happening, but deniers also dictate Republican Party policy. Republican policymakers constantly invite deniers to testify in congressional hearings, including many of those featured on the Skeptical Science misinformers page.

There is no symmetry on the other side of the aisle. In those same congressional hearings, Democratic Party policymakers invite mainstream climate scientists to testify. Their party policy is based on the consensus of 97% of the climate science community.

Ultimately, the issue boils down to a warped ‘Overton Window’ – the range of ideas tolerated in public discourse. In the real world, we have climate deniers on one extreme, alarmists on the other, and mainstream climate science in the middle. But the public discourse is warped – we instead have a heavy focus on climate denial among conservative media outlets and policymakers, a heavy focus on mainstream climate science among reputable media outlets and liberal policymakers, and the alarmists are largely ignored. Michael Tobis nicely diagrammed this in the climate Overton Window:


 The climate Overton Window. In the public discourse, there’s a heavy focus on climate denial and mainstream climate science, while the more alarmist outcomes are largely ignored. Illustration: Michael Tobis and Stephen Ban.

But there are some alarmists

That being said, there are a few reasonably well-known individuals who could be accurately described as climate alarmists. The most prominent is Guy McPherson, who decided in 2002 that climate change would likely drive humans to extinction by 2030. Sixteen years later, we’re now more than halfway to 2030 and the global human population has grown from 6.3 bn to 7.6 bn. It’s quite safe to say we won’t go extinct in the next few decades.

McPherson’s case basically boils down to arguing that feedbacks like large methane releases will soon kick in, causing a rapid spike in global warming that will lead to global extinctions. One of his primary pieces of supporting evidence is that Earth System Sensitivity – which describes how sensitive the climate is to the increased greenhouse effect over millennia – is higher than the shorter-term climate sensitivity.

That was essentially the gist of a recent study profiled here in the Guardian. Over millennia, global temperatures and sea level rise will continue to rise beyond what climate models predict will happen over the next couple of centuries. But these are slow feedbacks, and as such won’t kick in within the next few decades. Scott Johnson did a very deep dive into McPherson’s flawed arguments, for those who want to learn about them in greater detail.

As another example, Peter Wadhams predicted in 2012 that the Arctic would be ice-free in the summer by 2016. In fact, the summer of 2012 saw a dramatic decline in year-to-year Arctic sea ice extent (down to 3.6 million square km), which Wadhams believed would become the norm. That hasn’t yet been the case – there were 4.7 million square km of Arctic sea ice in the summer of 2016.


 September Arctic sea ice extent. Illustration: National Snow and Ice Data Center

It’s worth nothing that Wadhams gets most of the climate science right. There is absolutely a long-term decline in Arctic sea ice, which is in the midst of what many have described as a ‘death spiral.’ And Arctic sea ice is thinning rapidly. The Arctic will eventually be ice-free in the summer, but not within the next few years. According to Met Office Chief Scientist Julia Slingo, 2025–2030 would be the earliest date for an ice-free Arctic summer, and 2040–2060 is more likely. Wadhams also believes that there may soon be a large methane release from the Arctic, but a review of the relevant research suggests this isn’t a near-term concern:

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Comments 1 to 49:

  1. Its hard not to make alarmist appeals in arguments.  For example, I've begun telling people that once we double CO2 (i.e. hit 560ppm), Earth will likely hit a 3C anomaly within 50 years (or around 2100).  At 3C we'll be hotter than pre-industrial as the last ice age was colder.  I then ask them to consider if countries would be economically impacted if they suddenly found themselves in the depths of the last ice age (according to this graph of the last 400,000 yrs of global temperature, ice ages run about 6F, or 3C, cooler than pre-industrial).  If we'd find it difficult to run our countries in an ice age, why should we think 3C hotter than pre-industrial will be any easier?

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  2. Can Michael Tobias diagram of professional opinion be added to the SkS graphics page?  I have wanted to cite it in the past but was not able to find it.

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  3. I wish Mr. Betts would stop using the term "alarmist" over and over and over. It's a common dog-whistle term used by deniers. The article he cites supposedly debunking McPherson is over 4 years old. The basic argument seems to be that the bad things predicted by McPherson, Wadhams, and many others btw, haven't happened yet. We know that. So it's an argument over how fast methane can be released, how soon all the ice melts, etc. No mention of "global dimming". To say that the "alarmists" are wrong is a little premature. There is an impressive roster at the Arctic Blogspot site, not just two people as implied in this article. And I am convinced that a great many Climate Scientists are, privately, just as concerned as McPherson and Wadhams. This is why Arctic Blogspot uses the pseudonym "Sam Carana". Anyone being publicly "alarmist" may lose their jobs! Many Climate Scientists have left the US because they and their families receive death threats! But buy them a beer, and I'd bet they don't dismiss even the most dire predictions. We simply don't know what will happen, but the temperature increase is likely to be exponential, not linear. It's getting hot out there. All over.

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  4. The term 'alarmist' is indeed an annoying dog whistle and smear campaign. Some people have labelled me an alarmist for simply saying climate change is serious, or for claiming its caused by human activities. Much gritting of teeth.

    But climate change is alarming if you think of the long term consequnces. Perhaps the best retort is to tell people they should be alarmed, and then discuss the facts?

    This website should list a few genuine alarmists, but it should just be people with extreme claims well outside the IPCC, that are not supported by the peer review literature. You dont want huge lists of alarmists, because this would be shooting yourself in your own feet.

    A related example. Recently the Guardian wrote an article with claims sea level rise was doubling every seven years, and could reach 5 metres by 2100. The doubling claim was simply wrong, and only a couple of climate scientists claim sea level rise would be 5 metres by 2100. The Guradian should have said this.

    These sorts of mistakes and unexplained claims make "warmists" look stupid and excessively alarmist, and provide the denialist community ammunition to make them look stupid. I did a google search, and a couple of denialist websites attacked the Guardian article. It all provides people "sitting on the fence"  another reason to become sceptical of climate scientists. I agree with the article that these extreme fringe claims are not the main body of alarmism the denialists refer to, but it's still better not to have people making truly ridiculous claims.

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  5. I support the focus on correcting claims made by deniers of the developed, and continuing to be improved, climate science understanding; those who wish to claim that there is little need to change or correct the way things have developed.

    As an engineer I encountered many people who promoted what they wanted as something that would be OK. But, ethically, I had to screen out the unethical/unsafe/likely harmful options, not let them even be considered, no matter how much quicker or cheaper they were. And I would try to avoid over-conservative options, because responsibly limiting the cost or time required to build something is an engineer's objective - but never compromise the ethical protection of the public, workers and environment from harm caused by what was being done.

    And my MBA education in the 1980s included warnings about the unsustainable power of misleading marketing. Misleading marketing can be very effective at delaying increased understanding, which can increase the amount of undeserved benefit obtained from an activity.

    My MBA education and work experience also exposed the way that business-minded people can consider 'risk management' to be identifying potential risks and making sure someone else will suffer the consequences if the potential risk actually occurs. The fact that climate change impacts primarily affect future generations, or affect other people who cannot negatively impact the people who benefit from creating the consequence, are a perfect 'Business Risk Mitigation' plan.

    A different way to justify less effort spent on climate alarmist claims would be to present the case as a matter of ethically evaluating how important it is to address/rebut a claim. The ethical rule would be 'To increase the awareness and understanding of what is really going on and the application of that understanding to help develop a sustainable better future for humanity'. And the trigger for something needing to be addressed, and the urgency and magnitude of effort to address it, would be how Harmful (unethical) the claim is.

    Some people may try to argue against that definition of the ethical rule, but that can lead to a very productive discussion as they try and fail to justify a different Good definition of Ethical. I think it is a very easy definition to defend. And it makes it difficult for a climate science denier to justify their desired beliefs as being worthy of consideration.

    That ethical evaluation would clearly indicate that presentations of climate consequences that are possible, but more severe than what is currently considered most likely to occur, are not harmful and may be helpful. They are therefore not needing to be addressed.

    Outside of the scope of climate science, the same evaluation would indicate that 'the alarmist claims about the (lost opportunity for/damage done to) a portion of today's population if the required aggressive reduction of climate change impacts was effectively pursued (forcing better behaviour and creating a loss of personal perceptions of superiority among the least deserving of the more fortunate)', are harmful unethical 'alarmist' claims that require serious rebuttal effort.

    And Richard Betts would appear to be deserving of serious ethical rebutting.

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  6. Sooo, if you see that there is a fire in a building full of people, and it looks possible or probable the the fire will spread rapidly possibly causing much death and injury...if you run to pull the fire alarm, you are by definition an alarmist, right?

    Soooo, shouldn't we all be alarmists? Even the IPCC, which your own nice chart above shows is on the conservative side of accepted scientific opinion, shows really bad things coming down the pike toward us, certainly enough to be very alarmed about. And it is very likely that much of the IPCC is indeed to cautious and erring on the side of least drama.

    Of course, we should all avoid making concrete predictions that particular events will occur on particular dates or years...the system is just too chaotic for those to be anything but intelligent (or not) guesses.

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  7. I often watch talks by Kevin Anderson and Clive Hamilton, who has been heavily influenced by Kevin Anderson. The conclusions of their research is alarming, and the lack of response of the world to this crisis is equally alarming, even if it can be explained as the way humans deny what they don't want to believe.

    I don't mind replacing "alarmism" with a new word, but it too will then become overused and annoying. It is trully alarming what is happening and what we are not doing to address it.

    Despite the statistics that claim more than 50% of people believe in human-caused global warming, I don't personally know of a single person (other than my wife) who has made meaningful changes to their life to address this crisis.

    To me that is alarming.

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  8. "It’s quite safe to say we won’t go extinct in the next few decades."

    About the most UNscientific deduction I have ever heard. Its like saying;

    "I woke up this morning and I'm not dead therefor it is safe to say I will not die for years"

    Mcphersons scenario is plausable if not immediately so. That alone should alarm everyone on the planet to the extreme.

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  9. To add to what jef@8 said, one would hardly call Prof. Richard Alley an alarmist. Yet Prof. Alley himself said that early in his research career they did not publish their actual findings on how rapidly the climate can shift from one state to another (watch here) because they could not believe that the climate could switch from one state to another in a matter of years. It took he and his colleagues some time to get comfortable with the concept that there are "Dragons" out there, that could cause rapid changes in climate. So we cannot be sure of anything except that pushing the climate as hard as we are will not have a happy ending. All that we are discussing is whether it takes years, decades, or until the end of this century.

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  10. For the general public, I believe it is important to address the alarmists'misinformation as it is for the denialists'. Alarmist claims and predictions aren't being ignored. The denialists get a lot of traction consistently reminding the public of exaggerated claims and predictions. It's a great tool for the denialists, with no scientific arguments, to trash the notion of human caused climate change. 

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  11. 15 years ago James Hansen was called an alarmist because he claimed it was possible (not likely, only possible) for there to be 5 meters sea level rise by 2100 when the IPCC was estimating something like 0.3 meters.

    Now high sea level is commonly estimated as 2 meters and a significant number (not a consensus) of top scientists agree that 5 meters is possible.  Hansen's 5 meters no longer can be called "alarmist", it is just a high end estimate.  The IPCC estimate from 1990 is clearly wrong (much to minimalist) and was incorrect even when it was published.

    The same holds true for estimates of the disappearance of Arctic sea ice.  15 years ago they estimated 2100 before the ice was gone and now 2030 is a more common estimate.  The OP states "Peter Wadhams predicted in 2012 that the Arctic would be ice-free in the summer by 2016" which is incorrect.  Waldhams predicted ice free conditions in 2016 +/- 3 years.  That includes 2019 which has not yet passed where I live.  If next year has melting conditions like 2007 with the current thin ice Waldhams could still be correct.

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  12. Johnboy,

    It is impossible to make the deniers happy.  We just had the 30th aniversity of Hansen's senate testimony.  His projections have proven to be extraordinairly accurate and the deniers loudly claim that he was alarmist.

    The graph of expert opinion versus what is discussed in the media (in the OP) shows that realistic evaluations of future problems is not accepted.  Those considered "alarmist" are scientists at the high end of what is possible.  Only the low end of possible is allowed to be discussed.

    Only 10 years ago deniers used the term "catastrophic" global warming (CAGW) to insult the IPCC and scientists in general.  Scientists never used that term because it was "alarmist".  Today it is common for scientists to state that problems like drought, sea level rise, increased storms and flooding are potentially catastrophic.  What was considered "alarmist" 10 years ago is now the mainstream opinion.  

    Your suggestion of muzzling scientists who you consider "alarmist" would just shift the discussion even more to the denier side than it is already.

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  13. The term "Climate Alarmist" is not mutually exclusive form "Climate Science Denier".  Search 'Grand Solar Minimum' on youtube and you will find many videos excplicitly rejecting AGW yet warning of impending doom (crop failures, food shortages, starvation) as soon as this year due to the GSM which they are certain is already underway.  They are now attributing every natural event from droughts to volcanoes to earthquakes to a solar variation that is still well within the range of behavior over the last century.  It is hard to call this anything but alarmist.  Compared to these baseless warnings, a calculation that Florida could be submergeed in a few hunded years sounds pretty sober and contemplative.

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  14. The only site that I have seen that I would call 100% bonkers alarmism is Their home page claim that temps will be +10.02C by 2026 is nothing but ridiculous, non-science lunacy (I love the "0.02" precision of their number). Their claim is so outlandish, that part of me thinks that they are really a cover group for the larger, open denialist groups. Once 2026 comes, and we are in the range of ~1.1-1.3C (running average), then this cover group's real ploy will then have reached its full tactical intent, giving the denialist establishment a gift to show how "stupid all the climate change nuts are out there".

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  15. How about these alarmist, extreme views? Does the time scale matter?

    "We are close to the tipping point, where global warming becomes irreversible. Trump's action could push the Earth over the brink, to become like Venus, with a temperature of 250 degrees [Celsius], and raining sulfuric acid." Stephen Hawking

    "[I]f we burn all reserves of oil, gas, and coal, there is a substantial chance we will initiate the runaway greenhouse. If we also burn the tar sands and tar shale, I believe the Venus syndrome is a dead certainty." James Hansen

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  16. Evan:

    According to Mashable:

    "Hansen himself corrected his theory later on, writing that Venus-like conditions in the sense of 90 bar surface pressure and surface temperature of several hundred degrees "are only plausible on billion-year time scales"

    GOOGLE says many scientists came out and said that Hawking was incorrect when he made his statement.  This never happens with denier statements.  In addition, Hawking is not a climate scientist.

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  17. Evan, in his Exaggerations paper, Hansen walked back from a Venus-style runaway for the Earth, but readily maintains that we can still make the biosphere inhospitable to civilization as we currently enjoy it.

    "With the more realistic physics in the Russell model the runaway water vapor feedback that exists with idealized concepts does not occur. However, the high climate sensitivity has implications for the habitability of the planet, should all fossil fuels actually be burned.

    Furthermore, we show that the calculated climate sensitivity is consistent with global temperature and CO2 amounts that are estimated to have existed at earlier times in Earth's history when the planet was ice-free.

    One implication is that if we should "succeed" in digging up and burning all fossil fuels, some parts of the planet would become literally uninhabitable, with some time in the year having wet bulb temperature exceeding 35°C.

    At such temperatures, for reasons of physiology and physics, humans cannot survive, because even under ideal conditions of rest and ventilation, it is physically impossible for the environment to carry away the 100 W of metabolic heat that a human body generates when it is at rest. Thus even a person lying quietly naked in hurricane force winds would be unable to survive.

    Temperatures even several degrees below this extreme limit would be sufficient to make a region practically uninhabitable for living and working.

    The picture that emerges for Earth sometime in the distant future, if we should dig up and burn every fossil fuel, is thus consistent with that depicted in "Storms" — an ice-free Antarctica and a desolate planet without human inhabitants"

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  18. Steven Hawking probably knew his days were numbered, and wanted to give humanity a warning about climate change, something I find pretty admirable. He was unable to converse at length, so chose a few hard hitting words. His scenario is however incredibly unlikely.

    The IPCC reports are so conservative its ridiculous, and they are so nuanced and complex the big serious issues become lost from the publics perspective.

    But if you bring forwards very unlikely and extremely scary scenarios like Hansens or Hawking, it can possibly have the reverse effect of whats intended. 

    I think more attention needs to be paid to sea level rise scanarios like 2 metres,  and dangerous but plausible biosphere issues, because all these can be defended as plausible with some decent evidence. Imho this is the sort of thing the climate community needs to unite behind.

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  19. I would clarify that I mean 2 metres of sea level rise by 2100. We know considerably more is locked in longer term as well, but this century is particularly important because of all the existing infrastructure.

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  20. I was not aware that Hansen had walked back this statement, so appreciate the correction Michael and Daniel. Still, we are talking semantics, whether we trigger runaway greenhouse effects or just cause mass extinction due to one of the other major effects of global warming. So even if such acclaimed scientists have walked back their most dire forecasts, it is notable that they made them at all, because both of these men are (were) great thinkers and scientists.

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  21. "Alarmists"?

    A new study based on evidence from past warm periods suggests global warming may be double what is forecast.

    => Global warming may be twice what climate models predict

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  22. Scratching the 1 5°C Jazz


    Watch the concert here =>

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    Moderator Response:

    [DB] Please restrict image widths to under 500, please.

  23. Sir Charles @21-24,

    The primary source may be an proper point of referenece.  And that is Fischer et al (2018) 'Palaeoclimate constraints on the impact of 2 °C anthropogenic warming and beyond'

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  24. Michael Sweet @ 12. I hear you but my concern is that the denialists are constantly reminding the average Joes out there (like me) of exaggerated or unfulfilled predictions, including distorting them. They often get away with equating alarmism with climate science in the eyes of the public. I think the scientists need to get out front of this to continue to bring the fence sitters into the fold.

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  25. "I hear you but my concern is that the denialists are constantly reminding the average Joes out there (like me) of exaggerated or unfulfilled predictions, including distorting them.'

    This is my concern as well. Saying stupid stuff like "climate change will cause human extinction within 30 years" is not going to convince either denialists or "fence sitters". Such claims are easy to ridicule and disprove.

    What will be more likely to convince fence sitters are defensible projections with some evidential basis. This would include sea level rise towards 2 metres or maybe slightly more this century, serious lethal heatwaves, and the possibility of abrupt climate shifts and other things. That is "alarming enough" and can be substantiated with evidence, historical examples, and physics. 

    And it all comes done to how we define "alarmist" and of course nobody is going to really agree on this. It's a term that will continue to be thrown around like throwing mud. I tend to think while I dislike the term, it's best to "take it on the chin" and say maybe we are being alarmist, but with pretty good cause. But you then have to be able to back your position with good evidence and facts.

    Politicians are often "alarmist" . Sometimes their alarmism works, but sometimes it doesn't when people see through them. Extreme alarmism is a risky card to play.

    Ultimately you have to be able to credibly back your position. J Hansen is obviously some sort of genius, but for me straddles the ground between the possible and the impossible and his sea level rise predictions require a lot of conditions to occur. One should however justifiably argue even the remote possibility he is right is enough to justify urgent action.

    Of course the denialists often twist sound predictions to make them sound false, for example using Hansens scenario A predictions when the only prediction that makes sense is scenario B. But thats another matter. It seems like theres no option but to patiently rebut this sort of thing, or is there another way?

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  26. Reading the recent comments and thinking more about what needs to be done, I am revising/expanding my comment@5.

    I will, however, preface this by saying that the most important challenge to overcome is the ability of the less ethical among the wealthy and influential people to get away with misleading marketing appeals triggering passionate unjustified responses in support of excuses for causing harm to the future generations of humanity (appeals that make people primitively react selfishly and resist performing the more advanced human activity of thoughtfully considering things to help improve the future for humanity).

    It is important to understand the difference between Engineering Risk Management and Business/Economic Risk Management.

    I presented a common Business Risk Management method in my comment@5. In addition to liking to have others suffer any negative consequences, the business/economic approach attempts to justify what is done (claiming it is acceptable) by discounting future negative consequences and comparing that reduced perception of harm being done to others with the perceived lost opportunity (or cost) that some people today would experience if the amount, or risk, of future harm to others was reduced.

    Engineering Risk Management is different. It strives to reduce the chances of negative future consequences. The way it works is evident in the development of Building Codes and design codes for special items such as Dams. It is important to severely limit what is allowed because once harm has been done it can be very difficult to properly compensate those who were harmed and properly penalize those who benefited from the riskier more harmful approach.

    Canadian, US and many other Building Codes are based on designs statistically having a small chance of experiencing an event that would result in damage to any part of the structure. And the design of the structure would strive to allow all the occupants to be safe and safely exit the building even though the building is now damaged and may no longer be able to be used. The code minimum requirements are established to ensure that the statistical probability of damage occurring to a building is limited to a 1 in 50 year event (like a 2% chance of occurring).

    The requirements for Dams are typically more stringent because of the amount of harm that could be caused by the dam failing. A common requirement for dams is that they be designed to safely manage a 1 in 100 rain event without wave action resulting in any water reaching the top of the containment features of the dam, and be capable of holding the expected water from at least a 1 in 1000 year event without risk of failing. That is like protecting against an event with a 0.1% chance of occurrence.

    And with the Building Code and Dam Requirements, it does not matter how much cheaper or quicker an alternative is. The minimum requirements must be met. In a way, the codes set hard limits on economic/business options. And engineers are ethically responsible for not budging on those hard limits.

    For an issue like climate change (and so many other things), the Engineering Risk Management approach should be applied, setting hard limits on Business/Economic considerations and the way that options are evaluated. Engineering Risk Management also screens out (eliminates/dismisses) options that would result in harmful future consequences. Those options don't get to be considered no matter how desirable those options may be to someone or some group.

    The risk avoidance criteria for Dams is based on lower probability extreme events than the criteria for a building. The criteria for the planet should be based on lower probability extreme events than is used for Dams. I have seen many reports of evaluations indicating that humanity could experience livable conditions on this planet for hundreds of millions of years (before the changes of the Sun result in climate change that makes it too difficult to sustain life). Perhaps 1 in a billion is the more appropriate Engineering Risk Limit basis for global livability impacts like climate change impacts.

    That is essentially the same as the common sense understanding that it is unacceptable for any portion of current day humanity to be benefiting in a way that causes negative consequences for future generations.

    That would be the result of ethically altruistic thinking, pursuing increased awareness and understanding of what is really going on in pursuit of the development of sustainable improvements for the future of humanity and, as a minimum, protecting the future of humanity from harmful consequences.

    Science is by default, when being done properly, Ethically Altruistic. At its best it, a-politically and without potential bias for economic benefit, develops improved understanding and identifies required corrections, including corrections of economic and political developments.

    So the 'climate alarmist' evaluations deserve to be rigorously evaluated. If they are found to be 'based on good reasoning and are more probable than 1 in a billion' then the most severe of those probable events should be promoted as the proper basis for economically evaluating the acceptability of developed actions, and alternatives being considered, by the current day population.

    Attempts to defend much of what has economically/politically developed, including attempts to defend the failure of leadership (political and business) to responsibly limit the creation of additional climate change impacts will inevitably fail such an evaluation. It is common sense that what has developed cannot be justifiably defended.

    The lack of responsible actions from the wealthier and more powerful people can only be excused by misleading marketing claims. That must be corrected; the sooner the better, no matter how unhappy some people are about being told that they have developed unacceptable desires and are required to change their mind and actions.

    SkS cannot help but be Politically Correcting. People claiming that it is unacceptable for SkS to be seen as political, meaning politically biased, need to be challenged to justify why they want to protect understandably unacceptable developed economic and political beliefs from being corrected. Why do they want to believe that Ethical Altruism should not be limiting or correcting Egoism/Selfishness?

    Another way to say that is that SkS strives to be ethically altruistic, which can only be perceived to be Political if some political groups have allowed egoist/selfish desires to over-power their human ability to thoughtfully consider their actions, over-powering the ethical altruistic interest in striving to be more aware and better understand how to help develop sustainable improvements for the future of humanity.

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  27. A further revision/expansion of my revision/expansion @26

    What I referred to as Engineering Risk Management is just an example of appropriate Risk Management. It is the approach that should be used to evaluate the acceptability of any human activity. The developed Business Risk Management approach I presented in my comment@5 is undeniably unacceptable.

    As a General Rule: Increased awareness and understanding of what is really going on (science, but also so much that isn't called science and can't be confirmed by experiments in a lab), is essential to advancing humanity/civilization. And the application of increased awareness and understanding needs to be governed/limited by thoughtful consideration to avoid harm to others (ethical altruism). Everyone who ethically altruistically self-limits their actions should be free to do as they please. Anyone who tries to act less ethically needs to be corrected. Anyone who resists being corrected needs to be kept from having any influence on others until 'they learn to change their mind'.

    That is not new. It is my 'newest way' of expressing something that has been presented many times before by many people including Plato's idea of Philosopher Kings. It is another way of addressing John Stuart Mill's warning about allowing people to grow up mere children. It also exposes that law making also needs to be governed by ethical altruism or the laws and their enforcement could be illegitimate/unsustainable.

    It is an understanding that seems to constantly need to be re-learned because of the tendency for people to allow their primal instinctive reactions to over-power their advanced human thoughtful consideration. Only the least fortunate, most desperate, have an excuse for allowing their primal needs to over-power their ability for thoughtful consideration.

    Regrettably, the Constitutions of many nations do not include this fundamental General Rule or Guiding Principle. As a result, their law making can be unjustifiably governed by unsustainable, but temporarily gotten away with, popularity and profitability.

    That General Rule undeniably makes the actions of people who deliberately develop misleading marketing messages against increased awareness and understanding of climate science undeniably harmful. And the 'more successful' such a person appears to be, the less acceptable their actions are.

    The shift of culture in America from a Culture of Character to a Culture of Personality was a significant unhelpful change that needs to be corrected (see Foot Note).

    Increasing the awareness and understanding that less ethical/altruistic actions can get away with an unjustified competitive advantage in freer competitions for popularity and profitability may help change the way people respond to messages, change what impresses them most. It may help them think about the reaction that the message triggered and evaluate whether that triggered reaction was helpful to developing a sustainable better future for humanity, helped achieve the Sustainable Development Goals - did not harm the achievement of any of the goals. Passion triggering messages can be helpful, but often they are knowingly being abused for harmful purposes.

    Foot Note:
    Part of what happened to ethics is the shift of recognition of merit from 'Justifiably Helpful to Others and the future of Humanity' to 'Populist Celebrity - measured by power, popularity and profitability'.

    Susan Cain's “Quiet: The Power of the Introvert in a World That Can't Stop Talking” refers to cultural historian Warren Susman's work identifying that America went through a culture shift from a Culture of Character to a Culture of Personality in the late 1800s and early 1900s. His evaluation included a review of self-help books where he identified the dramatic shift of terms used to describe the desired person (to the detriment of people wanting to be helpful developers of a sustainable better future for humanity).

    In the Culture of Character the most common terms were: Citizenship, Duty, Work, Golden deeds, Honor, Reputation, Morals, Manners, Integrity (behaviours that everyone could aspire to, including scientists). The terms most common in the new Culture of Personality are: Magnetic, Fascinating, Stunning, Attractive, Glowing, Dominant, Forceful, Energetic (behaviours that scientists should not aspire to in order to 'sell their increased awareness and understanding').

    That culture shift was a shift from valuing ethical altruism and the pursuit of increased awareness and understanding of how to be helpful to others, to distraction from the pursuit of sustainable improvement for humanity and excusing selfishness and individual freedom of belief and actions.

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  28. OPOF @26 &27, I can relate to the risk management issue, because I also work in a design profession, and we have both issues of risk, technical codes, and codes of practice and professional conduct. I think the dam analogy is quite compelling.

    The whole concept needs developing further. Psychological research has discovered we quantify risk and probability all the time in all our decision making. As we all know normally we manage risk on the basis of how probable the risk, so the more the probability of risk, the more caution we have. But we also quantify the level of risk, so very low probability extremely high risk scenarios can justify a lot of caution as well, especially if the outcome cannot be reversed. But I think we are not as good at this.

    And despite this, people do take enormous risks where the outcome is potentially certainly instantly fatal and probabilities are low for example extreme sports. They possibly regard the planet in the same way, and you dont need to be a genius to know which side of the climate debate they are likely to be on.

    Individuals perhaps think they can escape climate change risks, especially if they have plenty of money. This will ultimately not be so easy.

    The thing is with climate change it effects the entire planet, so while extreme scenarios are perhaps low probability, they are high risk, and also affect billions of people. In addition the costs of remedying a catastrophic climate scenario would be vast. Therefore  the community is surely justified in minimising the risk by taking a united approach.

    I think we do have to to convince people we are dealing with a potentially very high risk situation without exaggerating, or sounding like "chicken little" and inviting ridicule.

    For me the complexities of altruism and selfishness would be best resolved by simply evaluating policies on the basis of whether they are fair to all the people involved, (and ultimately this includes everyone in society). So for me it comes down to what is "fair and reasonable" and this is a key value people need to unite around, if we were to reduce the issues to the simplest possible form. Of course theres much more to it, but this is the simplest way of summing it up for me personally anyway.

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  29. nigelj@28,

    I agree, but would add that every future human needs equal consideration, without discounting the consideration of people in the future. And that makes it difficult to justify any unsustainable activity.

    I often quote a longer portion of the 1987 UN Report "Our Common Future" that includes "... We act as we do because we can get away with it ...".

    The follow-up to "Our Common Future" is "Back to Our Common Future" which is a summary of the UN's “Sustainable Development in the 21st Century” (SD21) project. That document includes specific mention of the need for all nations to include consideration of the future generations in their policy evaluations and decision making.

    And the Sustainable Development Goals, which include Climate Action, are all about consideration of the future generations.

    No rich or powerful person has an excuse to be unaware of this or to misunderstand the importance of sustainable development. The ones fighting against the increased awareness and understanding of the required change of direction of development, and the corrections of what has developed, clearly need to be effectively targeted for correction.

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  30. It would be nice to have a full debunking of that arctic news blogspot. I went to the "deep dive" on debunking Guy McPherson and the person dismissed the idea that methane could be released on a massive scale by noting sea temps had been about the same 200k yrs ago (and it didn't happen then) and also that Archer does some back of the envelope calcs showing it won't be a problem.

    Note though that GHGs were about half what they are now, 200k ago.

    Note Alley's work (as someone mentioned above).

    Note Archer's history on various parts of artic behavior (e.g., permafrost in which he didn't include the effect of microbes), which he always corrects himself later on. But notice how his timelines have changed over the last 15 years.

    The problem with arctic news blog is it's harder to debunk than McPherson. They do cite lots of papers. Some of it is new lines of inquiry, but the direction they point is quite dramatic (Sharkova et. al., e.g.).

    Considering PETM and Siberian Traps events happened around 500 — 1500 ppm CO2, and Alley has shown a very good case that global climate can change in a matter of 5 years, and we've trapped a great deal of heat in the ocean that hasn't come out to play yet and we already have 2ce as much CO2 as 200k ago...

    They make a good point as to the possibility.

    What they don't really flesh out is that, if there is a sudden climate flip and many crops fail along with massive drought, the global capitalist system could grind to a halt for a bit. This could lead to a lot fewer particulates in the air, which could lead to very fast (others have researched this pretty well from what I can tell) warming.

    So please, Skeptical Science, fully debunk these guys. Point out what they are missing in your usual ultra thorough manner.

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  31. I think all environmental organizations were damaged by the intentional alarmist predictions of Paul Ehrlich and others back in the 70s. So I think it is important to call out the few extremists and explain why mainstream scientists think they are wrong.

    SirCharles @21, I think the widely publicized news on this article is somewhat alarmist (though the paper isn’t).

    MA Rodger @23, Thanks for the link. I downloaded the pdf of the paper.
    I thought this subject was treated pretty well in the Ars Technica article reposted on this site on June 28.
    (Sorry, can’t get link tool to work. Are there instructions anywhere?)

    Nigelj @18 I think the conservative conclusions of AR5 have caused some damage. California communities are now looking at a realistic possibility of 6.5 ft of SLR by the end of the century while the Summary for Policy Makers had given a maximum of 0.98m. Granted a couple of 2015 papers were game changers in the area of SLR but the following comment from the SPM, in retrospect, seems exaggerated on the conservative end. “Based on current understanding, only the collapse of marine-based sectors of the Antarctic ice sheet, if initiated, could cause global mean sea level to rise substantially above the likely range during the 21st century. However, there is medium confidence that this additional contribution would not exceed several tenths of a meter of sea level rise during the 21st century.”

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  32. dkeierleber @31, I agree about Paul Ehrlich. These huge catastrophic claims are risky to make, because  if they dont eventuate they destroy the credibility of the entire environmental community and feed the denialists.

    Having said that, we dont want to muzzle scientists, like someone said above,  and sometimes the extreme alarmists are right. And Ehrlich  was right in principle, population growth is a huge problem.

    The book "Limits to Growth" made scarey predictions that didn't eventuate, but fortunately it stated these were based on known mineral reserves, and this reality would likely change over time. I think its important to "qualify your predictions", but then we have the huge problem that the media often dont report the qualifications.

    The IPCC sea level rise predictions just look too low to me. And you raise a good point they are global averages, and not regional, and theres no obvious warning in the IPCC documents that regional rates could be very high. If there is it gets lost in the fine print.

    Yes the antarctic destabilisation seems exaggerated in the "conservative direction" by the IPCC. Or perhaps put it this  way: they are right to say the probable trend is it will only add about 200mm to sea level rise, but they should have said theres a 'possibility' it could be much more, or that such things cant be ruled out.

    The paleo climate evidence suggests the Antarctic destabilied rapidly at one point causing 2 metres of sea level rise per century, although this may have been preceded by several years of a  developed warming trend of several degrees. But we just dont really know. The important thing is climate change has been rapid in the past, so I think we cant rule it out now. We dont know enough to be able to rule it out.

    However when I see estimates that sea level rise could be 5 metres by 2100 this stretches credibility. Past examples of this are rare and relate to periods when there was far more ice on the planet. So this is truly an extreme scenario and seems very unlikely to be relevant to our situation.

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  33. It is not reasonable to assume that just because one boy cried wolf, that every call of "wolf!" is unjustified. Rejecting a whole field of science because of one (or a few) "alarmists" overstated the risks requires a pre-existing desire to ignore the risk to begin with. That's not to say that large numbers of people won't respond that way.....

    ...but remember: in Aesop's fable, the wolf does eat the sheep in the end.

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  34. How is one to avoid being an alarmist while stating what is in fact alarming? Paul Beckwith, for instance, is presenting observations and stating their implications. Alarmist? yours Frank

    0 0
    Moderator Response:

    [DB] Which observations and implications do you refer to?

  35. Responding here to an off-topic comment on another thread by PWadhams.

    The idea that the prediction of 2012 as reported by The Guardian:-

    "This collapse, I predicted would occur in 2015-16 at which time the summer Arctic (August to September) would become ice-free. The final collapse towards that state is now happening and will probably be complete by those dates."

    is 'Alarmist' or not; I would suggest that the idea of an Ice Free Summer Arctic Ocean 2015-20 is still an alarmist one. The transition from this year (which is certainly a long way from becoming ice-free) is surely far too big a leap to be considered possible. After 2018, in the remaining two years we would need something twice as spectacular as 2007 & 2012, and such spectacles one year after the other, to achieve ice-free conditions by 2020. And 2020 is a considerable extension to the initial prediction. (Do note the Slingo projection does not rule out 2025-30 for an ice-free summer Arcitc.)

    And even if the 'alarmist' label were misplaced, does it constitute an ad hominem insult? Surely not.

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  36. I think Dr. Waldhams has a good point.  He has been deliberately insulted with the derogatory term "alarmist".  

    If we compare his original projection of 2013-2019 with the Met Office of the second half of the century (after 2050) which one appears more likely today?  Why is it acceptable for a projection to be inacurate by being 50 years too late but alarmist to be 10 years too early?

    We do not yet know when the Arctic will become ice-free.  Until we know the result we do not know who will be closer to what actually happens.  Dr. Walshams is sticking to his projection from 2012.  The Met office has changed their projection from 2012 and made it decades earlier. 

    When Hansen first suggested that 5 meters sea level rise was possible most scientists rejected that idea.  The IPCC projection was less than 0.5 meters.  Hansen's recent paper, with 5 meters still one of the projections, had 19 co-authors.  Many of those authors are sea level or glacier specialists. I saw a paper recently that projected a high maximum of 3 meters (sorry no cite).  The US Climate report had a maximum of 8 feet (2.4 meters). 

    Every report increases the maximum.  Hansen's old projection is clearly much closer to current projections of the top end than the IPCC was when he made his projection.  Deniers continue to call Hansen "alarmist".  

    The graph from the OP sums it up:


    Scientists who are well inside the top of scientific thought fall into the catastrophic range in the graph and are muzzled.  It is unscientific to muzzle scientists who are in the range of scientific thought.  Dr. Waldhams is at the top of scientific thought, but since he made his projection the mainstream thought has dramatically shifted in his direction.  If we have melt conditions like 2007 next year who knows how low the ice could go.

    Hansen's paper from 2007 on scientific reticence and projections being low-balled for political reasons is worth reading again.  Time and again changes in the climate happen decades before scientists expected (arctic sea ice as a prime example).  We frequently hear of reporters saying scientists will say in private converstions that they think things will go much worse than the IPCC reports.   Calling those who say what they think "alarmists" is silencing everyone on the middle to right side of the graph, even though they are the majority of scientific opinion.

    I generally agree with Dana but he missed the mark with this post.

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  37. I don't think Hansen is an alarmist, because theres a small possibility he could be right, as opposed to so infinitesimally small its absurd. But opinions clearly vary in the climate science community.

    I think you also need visionaries that explore the outer limits of whats possible, but some claims have just been ridiculous, like claiming climate change could cause human extinction within 30 years. Temperatures would have to escalate massively, and even then small pockets of populations would survive in the colder regions. 

    I think a more plausibe scenario is sudden and very dangerous phase shifts in the climate, because it appears to have happened in past climates, although this might tend to be regional. But what regions? We don't really know. Nobody is safe.

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  38. Nigelj,

    My point is that when Hansen originally made his projection that 5 meters sea level rise was a better estimate than the IPCC estimate many called him an alarmist.  As time has passed the IPCC estimate has increased substantially while Hansen has maintained his top estimate.  Current high sea level estimates by mainstream scientists approach Hansen's estimate and he no longer can be considered "alarmist".  The original IPCC estimate (from around 1990) is clearly overly optimistic.

    "Alarmist" scientific estimates are very rare.  Meanwhile deniers like Lindzen, who in 1989 testified next to Hansen that he thought temperatures would stay unchanged, write Op-Ed pieces in the Wall Street Journal.  Curry publishes bullshit about Hansens 1989 projections.   The deniers claim that accurate projections are "alarmist". 

    We have to support scientists like Hansen and Waldhams when they speak their minds.  Otherwise we contribute to the censorship of the majority scientific opinion that currently occurs.

    In posts above I copied dates from other posts.  On review I find that Waldhams projection originally comes from 2007 when he suggested that sea ice could be completely gone by 2016 +/- 3 years.  Note his projection was made before the 2007 sea ice collapse.  At the time mainstream projections for ice free were 50+ years in the future.  He has maintained his projection to today wile mainstream projectins now are decadesw earlier than they were. 

    The mainstream has come closer to Waldham than they are to previous mainstream projections.  Even if it is 2030 before the first ice free year, Waldham will have been much closer when he made the projection.   Every January many of the posters on the Arctic Sea Ice Forum have long discussions about whether this year is finally the one where the ice will collapse.  Waldham's projection is still in play, to call him an alarmist is to contribute to scientific censorship.

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  39. michael sweet @38,

    The idea that for AGW 'alarmist' is the antithesis of 'denier' is probably something that folk can think about signing up to. Thus the characteristics of an 'alarmist' is that they ignore the rest of the science and insist that they and only they are correct (something impassioned academics often have a hard time not doing) and this when they themselves have no appropriate evidential support for their position.

    Taking that forward, Hansen did not have any proper support for his 5m SLR by 2100 under A1B until Hansen et al (2016). Now we have the basis for a hypothesis set out. And Hansen has always agreed that he is an outlier, even before the 2016 paper. To me, even if I find it hard to run with the hypothesis, I cannot brand Hansen as 'alarmist' over SLR. (Note that IPCC AR5 dismiss Hansen 2007 as being a heuristic argument that exceeds likely SLR limits set by other methods.)

    Where Wadhams differs from this is in statements such as (from 2009) "The data supports the new consensus view" which he has consistently seen as an iceless Arctic summer by roughly 2030 but with effective ice-free summers appearing ten years earlier. The basis for this prediction is dismissed by IPCC in a simlar way to Hansen's SLR, but I don't see a lot of development in the underlying basis for Wadham's position which is always a worry. This, and the failure to accept it his is an outliers' view, for me makes the Wadham's position that of an 'alarmist'. In terms of science, this is not un-fixable (as is the individual denialist position on AGW had the individuals concerned a mind to try to fix it). It can also be seen that the IPCC consensus position (which is roughly that ice free summers require 2ºC of AGW to happen) is not presented with a great deal of confidence. Thus the Slingo prediction of 2012 adding that a date of 2025-30 was not impossible. So there is a case forsupporting the work of those with a 2020 finding. But I still baulk at the poor support for the Wadham's position. I therefore don't see it as scientifically in play even though the discussion at Neven's forum may suggest otherwise.

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  40. Michael Sweet @38, I agree about Hansen. I can't bring myself to call him an alarmist, or to totally dismiss his claims, because there is some evidential basis for Hansens theories. Also although its unlikely that he is right about sea level rise, the small possibility he is right must be considered and not rubbished, because the consequences are so grave.

    I understand your point about how Hansens theories have evolved and the IPCC is a little bit in catch up mode. I never labelled him an alarmist even in the early days because I hate the term, because its obviously meant to be demeaning. But like I said its probably not worth taking it personally.

    But because the IPCC underestimates things doesnt mean all alarmists are right either.

    I tend to agree with MA Rodgers conculsions on Wadham, but again you wont find me accusing him of alarmism as such. I would just say he hasn't sufficiently backed his case.

    Definitions are important. Alarmism is normally defined as exaggeration or making claims without good reason. Like you said Hansen was on shaky ground in the early days, and probably did deserve to be dismissed as making implausible claims, but he has gained at least some support in the science community.

    But  if we are to use terms like alarmism, how much support in the scientific community is required to say someone is not an alarmist? Is one paper enough to demonstrate its not alarmism? I think it is, but only because nobody has firmly debunked Hansens claims, and instead they have simply stated that an awful lot of conditions would have to occur. But such conditions appear at least possible.

    But genuine alarmist scientists are pretty uncommon. I put Guy McPherson in that category because his claims are too far fetched. There might be some almost infinitely small possibility he is right, but is that enough to give them credibility? I dont think its quite enough to mean anything. We could argue almost anything in life is possible with some almost infinitesimally small possibility, but don't we need something more than that for them to rise above alarmism?

    I remember the ebola outbreak in Africa a year or so ago, and they were talking about possible exponential spread. To me this was possible and not alarmism, so in no way to I dismiss dangerous and / or extreme scenarios,  provided theres a possible mechanism that makes sense.

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  41. Michael Sweet @38, and I understand and agree with your point about supporting people like Hansen, to push back against the middle ground being labelled alarmist. But its a fine line because if we support people like Guy McPherson, I think this does damage credibility of science a bit.  Its absurd to defend every person making huge claims.

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  42. fpjohn at 34

    "How is one to avoid being an alarmist while stating what is in fact alarming? Paul Beckwith, for instance, is presenting observations and stating their implications. Alarmist? yours Frank

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    Moderator Response:
    [DB] Which observations and implications do you refer to?"

    Beckwith on Arctic Feedback is found on YouTube

    Accelerating Effects of Arctic Feedback: 1 of 2

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    Moderator Response:

    [DB] Given that there is no written transcript nor any listed sources being cited, that is scarcely credible when compared to the rich body of published literature.

  43.  I was recently reading comments at a Facebook post, where McPherson's was cited.  His claim is that by reducing fossill fuels emissions, the resulting  decrease of sulfur aerosols will cause worse warming.
     McPherson himself posted a comment. Here is an excerpt

    "Civilization is a heat engine, but slowing or stopping civilization heats Earth even faster than the ongoing warming resulting from this set of living arrangements. The impact of the aerosol masking effect has been greatly underestimated, as pointed out in an 8 February 2019 article in Science. As indicated by the lead author of this paper on 25 January 2019: “Global efforts to improve air quality by developing cleaner fuels and burning less coal could end up harming our planet by reducing the number of aerosols in the atmosphere, and by doing so, diminishing aerosols’ cooling ability to offset global warming.” The cooling effect is “nearly twice what scientists previously thought.” That this February 2019 paper cites the conclusion by Levy et al. (2013) indicating as little as 35% reduction in industrial activity drives a 1 C global-average rise in temperature suggests that as little as a 20% reduction in industrial activity is sufficient to warm the planet 1 C within a few days or weeks."

    Could someone comment on his claim about aerosols?

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  44. Here is the rest of what McPherson said in his comment

    "This Catch-22 of abrupt climate change, termed the McPherson Paradox by Bill R. Eddy, takes us down the wrong path regardless of the direction of industrial activity, assuming we are interested in maintaining habitat for vertebrates and mammals on Earth. A decline in the aerosol masking effect means loss of habitat for human animals, with human extinction soon to follow. Yet the liars at Deep Green Resistance, Extinction Rebellion, and other organizations are still promoting the dismantling of industrial civilization while claiming to be committed to the continuation of life on Earth."

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  45. ” . . . Actually, we show that aerosol-induced cooling is currently only ~0.4°C (see 3rd figure in the CarbonBrief article). Higher aerosol sensitivity would be incompatible with the observed mid-century hiatus. Plus, current warming would be overestimated if transient sensitivity was higher than we report. The neat thing is that the temporal evolution of (warming) anthropogenic greenhouse gases and (cooling) aerosols is not a mirror image. Hence they can both be constrained fairly robustly now.”

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  46. An alternative scenario?

    'However, new research published in Science by Hebrew University of Jerusalem Professor Daniel Rosenfeld shows that the degree to which aerosols cool the earth has been grossly underestimated, necessitating a recalculation of climate change models to more accurately predict the pace of global warming.
    And, they discovered that aerosols' cooling effect is nearly twice higher than previously thought.
    However, if this is true then how come the earth is getting warmer, not cooler? For all of the global attention on climate warming, aerosol pollution rates from vehicles, agriculture and power plants is still very high. For Rosenfeld, this discrepancy might point to an ever deeper and more troubling reality. "If the aerosols indeed cause a greater cooling effect than previously estimated, then the warming effect of the greenhouse gases has also been larger than we thought, enabling greenhouse gas emissions to overcome the cooling effect of aerosols and points to a greater amount of global warming than we previously thought," he shared.'

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  47. sailrick @43/44,

    Those quotes get a bit strong. The source of the quotes is this blog by McPherson which may help put them in context, but what is also required is the science lying behind these strong assertions.

    The link to the OP provided by Postkey @46 is part of this, but the underlying paper is Rosenfeld et al (2019) 'Aerosol-driven droplet concentrations dominate coverage and water of oceanic low level clouds'. Also cited in your quote @43 is Levy et al (2013) 'The Collection 6 MODIS aerosol products over land and ocean'.

    The basis for the strong message presented @43/44 is that coal-use emits both CO2 and SO2. The CO2 is raising climate forcing at a rate of ~0.02Wm^-2/yr. SO2 acts as a seed for aerosols and thus more shiny clouds which cool the planet. SO2 is very short-lived but provides a negative forcing which is not well defined (IPCC AR5 put it at -0.9Wm^-2(+0.8,-1.0) although note the recent work cited by Postkey @45 derives from Haustein et al (2019) 'A Limited Role for Unforced Internal Variability in Twentieth-Century Warming' (described in the CarbonBrief article & the RealClimate article). Haustein reconstruct the global temperature record using known forcings and conclude that the SO2 effect would be roughly -0.4Wm^/2.

    So simplistically, we have what is seen by some as a dilemma facing humanity. If we cut coal-use we will be faced by a net increase in climate forcing boosting AGW. But if we maintain coal-use to prevent such a boost, the CO2 would provide the exact same boost over coming decades (perhaps as few as 20 years) and the dilemma would still be in place.

    Yet it isn't quite as difficult as that. The coal-use will not cease overnight and there is a reduction in CO2 forcing (and also more quickly CH4 forcing which totals so-far 0.5Wm^-2 and of which a significant proportion is down to coal) once we stop CO2 emissions (or the reduction in a past contribution of a particular source once it is shut down).

    As for the strong message, a quick peek at the blog by McPherson shows some serious misrepresentation of cited material, serious enough to suggest the blog is entirely without merit. So I would be surprised if there is any actual support for the bold claim that there will be 2-3 degrees C warming over the period 2019-30.

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  48. An update to #47, concerning the effect of reducing negative forcing when FF-use & its resulting aerosol-causing pollution is cut, CarbonBrief have an item with coverage of recently-published Shindell & Smith (2019) 'Climate and air-quality benefits of a realistic phase-out of fossil fuels' [Abstract]

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  49. MA Rodger and Postkey
     Thanks for the reply. I had forgotten to check  back after posting my comments.  Then today, someone I was talking with brought up McPherson, and how stopping SO2 emissions will cause more warming.
      And that led me back here, seven months later.

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