By Stefan Hendricks. MOSAIC ice camp and RV Polarstern during its Arctic expedition on October 11, 2019, CCA-SA 4.0, via Wikimedia Commons.


Yes, it’s changing. Yes, we’re causing it. A climate scientist explains what we know, for sure, about the climate, and how we know it.

Thanks to Claire for inviting me to contribute to this conversation.[1]Claire Berlinski, the co-founder and editor of the Cosmopolitan Globalist She suggested I offer a broad overview: How do we know climate scientists are right—or at least, so overwhelmingly likely to be right that the scientific consensus should be the foundation of our energy strategy? Here, I’ll sketch some arguments for the consensus view.

A few years ago, I was invited to join my aunt and uncle, along with another couple, for dinner. The other couple, Dr. and Mrs. Paterson, as I’ll call them, had many questions about climate science. Dr. Paterson remarked that the Earth’s climate has undergone natural swings for millions of years, so he didn’t see how we could be sure that humans are changing the climate today.

I spent the next few minutes talking about climate and orbital cycles. The Earth’s tilt and precession cycles line up so that Arctic summers are cold, allowing snow to survive the summer and build up ice sheets in North America and Eurasia. The ice sheets grow large enough to change the climate in ways that favor more growth—for example, by storing more carbon in the ocean, so that the global atmosphere cools and the entire Earth enters a glacial period. This continues for tens of millennia, until orbital cycles favor summer Arctic melting. Ice sheets collapse, atmospheric CO2 rises, and we enter a warm interglacial period.

I explained that the timing and triggers are different for global warming caused by greenhouse gas emissions, but many of the underlying physical processes are the same. When I finished, Mrs. Paterson said, “That makes sense. Why didn’t someone explain that to me before?” It was one of the nicest things anyone ever said to me. The Patersons came to dinner as climate skeptics with open minds; they went home a bit less skeptical.

My uncle, however, was unmoved. He’s convinced that climate science is nothing but a jumble of hoaxes, hyperbole, and delusions. I no longer talk with him about climate science, since our arguments distress my aunt and are pointless.

I assume any subscriber to The Cosmopolitan Globalist who is not already convinced of the scientific consensus on climate change would have an open mind, so it’s worth some effort to outline the main arguments. I will begin with this essay, but will subsequently address points I’ve seen raised in the comments section.

How do we know that climate scientists are right? Obviously, scientists don’t know everything about the climate, so they keep measuring, modeling, and debating. But climate scientists are very confident of this statement:

The Earth’s climate is warming, and most of the warming is caused by humans.

When I say “very confident,” I mean confident in the way that medical researchers are confident that smoking raises the risk of cancer. This claim rests on a web of well-established theories, backed by millions of observations and model simulations, documented by thousands of peer-reviewed papers and painstakingly scrutinized reports.

Why so confident? Let’s assess the statement in two parts: the observation of warming and the attribution to humans. The evidence for warming since the mid 20th century is overwhelming. Nearly every location on the Earth’s surface has warmed—by an average of about 1.2 degrees C (around 2 degrees F) since the start of the instrumental record in the late 1800s. Every month since February 1985 has been warmer than the 20th-century average. Record daily high temperatures are about twice as common as record lows. The oceans are warming, at and beneath the sea surface. The troposphere (the lower part of the atmosphere, up to 10 or 20 km) is warming. The Arctic sea ice cover is thinning and shrinking. The Greenland and Antarctic ice sheets, and nearly all the world’s glaciers, are losing mass.

There are some complications, such as the relative sparseness of temperature measurements in places like the South Pacific and Antarctica, and biases such as the urban heat-island effect. Climate scientists have reliable methods to address these problems. About ten years ago, a distinguished physicist, Richard Muller, questioned the statistics and spent many months reviewing temperature data. He wrote a piece in The New York Times confirming that to his surprise, prior estimates of warming rates were correct (I found this extraordinary. Not many of us have written editorials saying that after a close look at the evidence, we changed our minds.)

Since the warming of the past few decades is unequivocal, what is the proximate cause? Scientists are highly confident that most of the warming is caused by increasing amounts of greenhouse gases in the atmosphere. By definition, a greenhouse gas is mostly transparent to visible light from the sun, but relatively opaque to the infrared radiation emitted back to space by the Earth. By trapping infrared radiation near the surface, greenhouse gases warm the Earth’s surface and its lower atmosphere. This effect has been understood since the 19th century and is easily shown in a laboratory.

CO2 is the most important greenhouse gas, but methane, nitrous oxide, and other trace gases add to the warming. Humans do not add another greenhouse gas, water vapor, to the atmosphere, but it amplifies the effects of the other gases since a warmer atmosphere holds more water. We know that greenhouse gas concentrations are increasing because we can measure them with great precision. We began monitoring CO2 at Mauna Loa in the 1950s. With somewhat less precision, we can track greenhouse gas concentrations about a million years into the past by analyzing air bubbles trapped in ice cores. Ice cores also allow us to estimate variations in temperature, which are well correlated with greenhouse gas changes. (The causation is mutual: Greenhouse gases increase temperature; and for more complex reasons, warming raises atmospheric concentrations of greenhouse gases.) Between glacial and interglacial periods, CO2 has varied in concentration between about 200 and 280 parts per million, or ppm. The value was about 315 ppm when the Mauna Loa measurements began in the 1950s and is 420 ppm today.

Is the observed warming commensurate with the increase in greenhouse gases? It is. Theoretical calculations, simple radiation models, and complex global climate models tell us how much warming goes with a given increase in CO2. There are uncertainties of about a factor of two. If CO2 doubles compared to the pre-industrial value of 280 ppm, we expect the climate eventually to warm by 2 degrees to 4 degrees C, maybe 5 degrees C if we’re unlucky.

Much of the uncertainty comes from clouds, which are infernally complex. We know that low clouds reflect sunlight and cool the climate, while high clouds absorb infrared radiation and warm it, but it’s hard to predict where low and high clouds will become more or and less prevalent.

Another complication is the variability in natural and human emissions of aerosol particles, which generally cool the climate by reflecting sunlight. Clouds and aerosols largely explain why some climate models predict more warming than others. But if we assume, for example, a 50 percent increase in CO2 and similar increases in other greenhouse gases such as methane, no model consistent with the laws of physics will simulate an unchanging or decreasing temperature.

Carbon is exchanged between the surface and the atmosphere by many processes, both natural and human. How do we know the extra CO2 is coming from humans? The strongest evidence comes from carbon isotopes. There are three isotopes of carbon in the atmosphere: carbon-12 and carbon-13, which are stable, and the rarer carbon-14, which is formed naturally in the atmosphere and decays over several thousand years. Fossil carbon—that is, the carbon in coal, oil, and natural gas—is depleted in carbon-13 and carbon-14. Increasingly, carbon in the atmosphere is also depleted in these isotopes, showing that most of the added carbon has a fossil origin.

In addition to measuring atmospheric CO2, we can independently estimate the total carbon added to the atmosphere by human activities. We find that only about half the emitted carbon remains in the atmosphere; the land and ocean take up the rest. This uptake is fortunate, since it has reduced the warming to date and gives us some cheap ways to remove carbon, for instance by planting trees.

Could other factors be contributing significantly to the recent warming? Orbital changes are too slow to be relevant. Besides greenhouse gases, the main external drivers of short-term climate changes are volcanic eruptions and variations in solar intensity. The sun has not become more active over the past few decades, and there have been no major changes in volcanic activity. Could the recent warming be a natural fluctuation, caused by changes in El Niño or other circulation patterns? This is extremely unlikely. Over the past 1,000 years, the Earth’s average temperature—deduced from tree rings, ice cores, and other natural records—has varied within a much smaller range than the recent warming. Temperatures today are the highest they’ve been in at least the past millennium, and probably higher than at any time since the last interglacial period, about 125,000 years ago.

In 1990, when I started learning about climate science, a majority of climate scientists thought it was caused by humans, but a sizable minority weren’t sure. By 2000, based on the evidence I’ve described, working scientists arrived at a near-universal consensus that humans are causing climate change. The evidence has grown ever stronger, but public opinion, for various reasons, has lagged the science by a decade or two.


I should like to correct an assertion offered by Adam Garfinkle in an essay that is otherwise scientifically unobjectionable. He writes, “[O]ur models cannot yet firmly capture the dynamic relationship between temperature and the mix of gasses in the atmosphere.” This statement is untrue, unless by “firmly capture” one means an impossibly high standard, like “capture without any significant uncertainty.” NOAA’s overview of climate models is correct:

Climate models are based on well-documented physical processes to simulate the transfer of energy and materials through the climate system. Climate models, also known as general circulation models or GCMs, use mathematical equations to characterize how energy and matter interact in different parts of the ocean, atmosphere, land. Building and running a climate model is a complex process of identifying and quantifying Earth system processes, representing them with mathematical equations, setting variables to represent initial conditions and subsequent changes in climate forcing, and repeatedly solving the equations using powerful supercomputers.

When someone says that models don’t do a good job of representing (or capturing) the dynamic relationship between temperature and GHGs, I understand them to be arguing that models fail adequately to represent the transfer of heat and other forms of energy between different parts of the Earth system.

But they do a very good job. For example, if GHGs are added to the tropical atmosphere, the added heat absorption will lead to greater evaporation and a stronger Hadley cell (i.e., rising of air in the tropics and subsidence at higher latitudes). The model might then predict more intense rainfall events in the tropics and drought in the subtropics, consistent with what’s observed. This is the kind of thing models do well, because the dynamics are based on fundamental principles such as Newton’s laws of motion and the conservation of energy. Translating these laws to computer algorithms is tricky, but climate scientists have worked on this for decades, and the methods are now very good.

Cloud processes are harder, in part, because the processes take place on small physical scales that can’t be resolved by global models. You would need very fine grid resolution—say, 1 km or less—and the resulting model would be too expensive for decade-to-century simulations. So scientists have to find other ways to get accurate answers without resolving all the relevant scales of motion. This is known as parameterization.

To use the term of art, the dynamical core is sound, but the parameterization of physical processes needs more work—and will always need more work, because climate models can’t have infinitely fine resolution. If Adam Garfinkle questions the dynamical core, he has misunderstood the problem.

In a subsequent essay, I hope to add some general thoughts on the epistemology of climate science.

Dr. X is a distinguished American climate scientist. To protect his family from abuse on social media and focus his energies on research rather than public debate, he prefers to remain anonymous.


1 Claire Berlinski, the co-founder and editor of the Cosmopolitan Globalist


  1. Well written and very clear explanation of a complex subject. Thank you for it.

    John Kerry, President Biden’s climate Czar, recently said,

    “Well, the scientists told us three years ago we had 12 years to avert the worst consequences of the climate crisis. We are now three years gone, so we have nine years left…”

    My question, Dr. X, is whether you think the data generated by climate scientists is so overwhelming and so amenable to precise analysis that scientists can determine the exact year when, absent dramatic reduction of greenhouse gas emissions, “the worst consequences” (whatever that means) will result?

    To put it another way, Is there now or has there ever been, a consensus of climate scientists that we are currently in a short window of now nine years where if we don’t take severe action calamity becomes inevitable?

    • Ronald STEENBLIK | May 3, 2021 at 3:58 pm | Reply

      The year 2030 is mainly significant because it was a nice round year, against which progress against various commitments on reducing greenhouse gas emissions could be adjudged. I doubt there are many scientists out there who would claim that they can say with certainty the exact date by which the worst consequences of climate climate change can be averted, in part because there are other variables that will affect that trajectory, not the least of which are economic and technological developments in the interim.

      Nonetheless, since so many countries made pledges to take climate-related action by 2030 (in the Paris Climate Agreement, under the UN Sustainable Development Goals, for example), it is natural for scientists to look for significant action by the world’s governments between now and that date. To me, that is what “12 years to avert the worst consequences of the climate crisis” means in that context.

      • The fact that 2030 sounds like a “nice round year” doesn’t sound very scientifically compelling. In fact, what it really sounds like is hocus pocus.

        Unless, Senator Kerry can point to an overwhelming number of peer-reviewed scientific papers which demonstrate that calamity ensues by 2030 if we don’t act, his statement is false; in fact it’s worse than that. It’s a lie. Is that the person who should be leading the American effort in the climate arena?

        By failing to correct the record, point out the folly of making definitive predictions and criticize the exaggerations of pundits and politicians, don’t climate scientists become complicit in deceiving ordinary citizens?

        I have another question for Dr. X and Ronald Steenblik. Last year, Governor Gavin Newsom of California said the Zogg wildfire near Redding California was proof that climate change was real.

        Is there any proof to the standard of near statistical certainty that the Zogg fire or any other recent California wildfire has as its major cause, human induced climate change? Or is Newsom’s statement as inaccurate as Kerry’s?

        • Claire Berlinski | May 3, 2021 at 6:15 pm | Reply

          (Rewritten for grammar.) No. No way to prove that; the comment was ridiculous. But there’s a logical fallacy at work if you mention this to implicate serious climate scientists, none of whom would actually say that and all of whom always diligently say the very opposite: “There is no way to prove this particular disaster was caused by climate change. However, we are extremely certain the Earth is warming.” There are people who can’t or won’t understand what they’re saying. But saying, “This fire was caused by climate change” does not invalidate the serious climate science. If that were true, we’d decide that a virologist who produced a coronavirus vaccine that’s 80 percent effective should be reviled because an especially loathsome politician insisted it would “totally protect you against getting sick.”

          • Fair enough, Claire, but I do think that climate scientists have done too little to point out the exaggerations, distortions and deception of the climate activists who speak in the name of climate science.

            In the United States, Democrats in particular like to claim that the Republican hordes are science-denying Neanderthals. My point is that whatever you want to call it, Kerry, Newsom and their ilk are not peddling science. They’re peddling pseudo-science at best and and hocus pocus at worst.

            Turning science into good public policy is hard-very hard. Getting it wrong can have bad consequences. Once public health experts were finished distorting the complicated work done by scientists with expertise in lipid metabolism, we ended up with dietary advice that caused a massive epidemic of obesity and Type II diabetes (thankfully, France, which never gave up butter for margarine or real cheese for cheese wiz escaped this anthropogenic dietary disaster).

            Similarly, climate activists are distorting the findings of climate scientists in ways that could have disastrous results.

            The policies needed to avert climate calamity, especially if Kerry’s 9 years is the time period in which we must act, will ruin the livelihood of tens of millions of people around the world. Americans are already losing good jobs with little hope of replacing the jobs they’ve lost with anything other than menial labor.

            By perverting the findings of genuine climate scientists, climate activists are doing something that is genuinely evil.

          • “Fair enough, Claire, but I do think that climate scientists have done too little to point out the exaggerations, distortions and deception of the climate activists who speak in the name of climate science.”

            I can proudly stand with you here.

            When AOC breathlessly declares the end of the world, scientists and skeptics alike should stand up and, with the mightiest hedged language they can muster, “That is statistically unlikely, however action would be prudent given our models, and we recommend setting concrete goals in order to reduce risk.” It’s not sexy, and it won’t grab headlines, but it’s what needs to be said.

            Unfortunately, this one facet of a much larger and more difficult problem. People are too reluctant to call out incautious thinking on their side of the fence. It’s probably because of the savagery of our discourse. I watched the Trumpists’ treatment of “RHINOs” in order to stomp out criticism with disgust. The same can be said of seeing members of the press calling liberals like Sam Harris “Alt-Right” because they don’t adhere to woke politics.

            Our fight is against all the inquisitors.

          • There’s a certain peril in extrapolating in front of a dishonest audience, as well.

          • I have to disagree with you Dr. Steenblik. John Kerry picked a year, 2030. He was selling the proposition that if we didn’t solve the problem of our carbon emissions by then, it was game over. Like many climate activists he did this with a specific purpose. That purpose was to scare the dickens out of ordinary citizens so that they would acquiesce to policies that were bound, in the short run at least, to ruin their standard of living.

            Unless you can identify a large cohort of genuinely expert climate scientists to affirm that nine years is all we have left to avoid calamitous climate change, Kerry’s false statement is about politics not science.

            I would love Dr. X to give us his opinion (understanding that it’s only an educated opinion) do we have exactly 9 years to avoid climate disaster? Do we have 10-50 years? Do we have a century? Is it already too late?

            Obviously the longer we have, the more gradual the changes can be made and the fewer economic dislocations can be expected.

            Another question I have for Dr. X and Dr. Steenblick is do you feel that having John Kerry and Greta Thunberg as the two most prominent spokespeople for the climate science community increases or decreases the credibility of climate science?

            Do you really think climate science will be more credible if climate scientists acquiesce to climate activists making statements that simply have no basis in science?

          • Ronald STEENBLIK | May 4, 2021 at 8:30 am |

            This string has little to do with the actual article. Neither John Kerry nor Greta Thunberg are mentioned in it. The two most prominent spokespeople for the climate science community? Since when? Yes, they try to refer to science, but their sphere of action is, respectively, international diplomacy and climate activism.

            I think I have said enough already about the relationship between science and diplomacy, the meaning of shared targets, and the necessary collective action it implies.

            As for activists, Greta Thunberg is a very passionate, articulate person. But only one voice among many. I have questioned some of her past statements on global fossil fuel subsidies, where it appears that she is referring to the IMF’s estimates of “post-tax subsidies” to fossil fuels ($5.2 trillion in 2017), more than 90% of which are not actually estimates of subsidies as commonly understood, but mainly estimates of the externalized costs imposed on society from burning fossil fuels. (See my pinned Tweet.) I’ve written to people who I think have her ear, to verify whether the IMF is her source, but have heard back nothing.

            I did listen in to the most recent U.S. House Subcommittee on the Environment hearing on fossil fuel subsidies, at which Ms. Thunberg testified, and I was afraid she would confuse matters by throwing out the IMF’s estimates of the USA’s “fossil fuel subsidies”, $649 billion in 2017, but she didn’t, so I was glad of that. The estimate that the Subcommittee itself was working with was in the neighborhood of $15 billion a year. That is 2.3% of the IMF number.

            P.S., It’s not “Dr.” (I worked on one, but did not finish) and it’s not “Steenblick” (there’s no “c”).

          • Sorry about the credential mistake and misspelling your name.

        • Ronald STEENBLIK | May 3, 2021 at 7:11 pm | Reply

          Ronald STEENBLIKjust now
          Internationally agreed targets are almost ALWAYS established with reference to a “nice round year”. That doesn’t make them any more or less scientifically valid. Scientists have looked at possible pathways towards outcomes that avoid reaching certain global average temperatures, so they can provide some idea of what actions (especially emissions trajectories) need to be taken by a specified date.

          In other words, the direction of causation is: scientists are constantly refining their models, but at some point they are asked to look at a specific date, one that it is easy for everybody to remember. Indeed, using “nice round numbers” is itself a signal that avoids the appearance of false precision. If the target date for certain policy outcomes was 2029, critics would be asking, “Why did they choose such a precise date?”

          The predictions from climate scientists of course have bands of uncertainty around them, which expand the further one looks into the future. What climate-mitigation actions get done in the short to medium term can have a big influence on the longer term, and especially the rate of change that would be needed in the future to avoid catastrophe if actions taken now prove insufficient.

          Perhaps this late 2019 report, co-authored by a team of international scientific leaders, helps explain what is behind the kind of statement that Kerry made. Again, everybody is focussing on what countries do between now and 2030, in part because the pledges beyond that date are much more vague, and the rate of reductions would be even more politically difficult to achieve.

  2. PSW-OFFICE | May 3, 2021 at 4:50 pm | Reply

    This is good. Thank you for rectifying.

  3. Sterling Thomas | May 3, 2021 at 5:43 pm | Reply

    I would like Dr. X’s comments regarding GHG measurements on Mauna Loa and the continuous 35 year (1983-2018) eruption of Pu’u ‘O’o on Kilauea Volcano’s East Rift Zone. This eruption ranks as the greatest in volume of magma disgorged from Kilauea in the last 500 years. How did the volume of CO2, SO2, H2S, CO, H2O, etc. emitted just down slope of Mauna Loa effect those measurements? And if not, why not? FYI: this December past, the eruption has began anew.

  4. Thomas M Gregg | May 3, 2021 at 10:36 pm | Reply

    This was very enlightening. The only problem is that it indicates no particular course of action.

    It may be that nothing can be done to halt or significantly retard climate change, for the complications of the problem go far beyond its scientific component. The problem being global, so must be the solution. But alas, the oft-spoken of global community is, like the basilisk, a mythical beast. So it will probably be found that the range of practical action is very narrow.

    This is not to say that action on the energy front would be futile. There are reasons other than climate change to develop and deploy cleaner, more efficient energy technologies. The one thing I’m sure we should not do is listen to John Kerry.

  5. Ken Snider | May 4, 2021 at 5:03 am | Reply

    “It doesn’t matter how beautiful your theory is, it doesn’t matter how smart you are. If it doesn’t agree with experiment, it’s wrong”. – Richard P. Feynman

    When the climate model results are compared with the last 40 years of global satellite temperature measurements, they do not match.
    The models, with a couple exceptions, project rates of temperature increase that are 2 to 3 times greater than the measurements.

    Unless you believe the rate of global temperature increase, as measured by the satellites and calibrated with weather balloons is wildly incorrect, the theory used to build the computer models is incorrect. The theory needs to be corrected so the computer models built on the theory match the data.
    The other possibility is the computer models fail to express the theory correctly and need correction.

    I believe humans are making some contribution to warming, but models based on a theory that is incorrect or models that fail to correctly express the theory will not help us accurately separate the human contribution from the natural warming. The current models are failures at prediction.
    Until they are corrected, the models cannot be relied on to tell us if the human contribution will make a difference that will be of any significance 80 years from now.

    I believe the scientific consensus, based on hundreds of studies of temperature proxies, is that more than 7,000 of the last 10,000 years of this interglacial were warmer than now. Some of the warming we are now experiencing after the Little Ice Age ended in the mid 1800’s is natural and to be expected based on the natural observed temperature cycles over the last 2,000 years.

    Until we can separate the natural warming from the human warming we lack adequate information to decide what, if anything, we should do.

    • Do you think rate of change is significant in trying to determine if we’ve contributed significantly?

      • Ken Snider | May 4, 2021 at 3:50 pm | Reply

        The divergence in the rate of change in the data and the models means the models are invalid.
        By significant, I mean will the change caused by human activity be noticeable to people in 2100. A change of 1 degree C in the average temp is well within the natural variation (which is likely to both warm and cool multiple times in that time frame) and would not be detectable by people going about their daily lives. A 10 degree C human contribution would be very noticeable. Unfortunately, the current models are incapable separating out and predicting the effect of the human contribution to warming. Until they are corrected to match up with data from the last 40 years, they are useless.

        • Sorry, I should have specified that I was referring to the data we’ve already collected, not the predictive models based on them. I think we can all agree about the uncertainties of extrapolation. But everything good science touches is going to have acknowledged uncertainties, so I wouldn’t let that paralyze me into inaction.

          With my apologies, I’ll try and rephrase:

          Even if we can’t separate natural contributions from anthropogenic, but we can determine the average global temperature up to this date, would a record breaking rate of change over the last several decades be enough to cause concern?

          • Ken Snider | May 4, 2021 at 7:34 pm |

            I refer to the last 2 paragraphs in my first comment.
            During this interglacial there is evidence of temperature changes likely more rapid than we are experiencing now. Our current rate of change is only “record breaking” if the time horizon is short.
            There are hundreds (probably over a thousand now) of research papers detecting evidence of the Roman and Medieval warming periods all over the world.

            The Romans had vineyards in England without the benefit of todays frost resistant hybrid vines. It was likely several degrees C warmer than today.

            The Vikings were farming in Greenland during the Medieval Warm period. It is too cold to do that today.

            As we continue warming out of the Little Ice Age, the change will not be constant. Some decades it will be faster and then there will be decades where the increase flattens out, much like the 15+ plus year pause in temperature rise that occurred recently.

            What is a “record” is pretty subjective. Especially given the sparse and subject to error temperature records before the satellites.

            Even if we decide increasing temperatures, natural or otherwise, will continue, this is a slow-motion disaster happening over many decades. Humans have always been good at dealing with slow-motion disasters. With our current rate of technological advancement, we should be getting better at it.

            Even if we decide to do something. We don’t know enough to know what measures would actually be effective. The IPCC says that if humans immediately stopped adding CO2 to the atmosphere, the result would a reduction in the increase in temperature by less than .5 C by 2100. That doesn’t appear very effective to me.

            Not that I think it is a good idea, but Bill Gates plan to block the sun with high altitude particles might be more effective at dropping temperature, if that is really what you want to do.

            I’m not really interesting in going back to the conditions of the Dark Ages or Little Ice Age with their crop failures, famines, depopulation, plagues, more wars and stormier weather.

          • I’m not going to be able to address with every direction you take your posts in, but you certainly deserve a response to most of it.

            “During this interglacial there is evidence of temperature changes likely more rapid than we are experiencing now.” This is the first time I’ve heard this claim, since it’s pretty radically different from the normal comparison of global averages. I will adjust my position accordingly if I can find a nonpartisan source to support it. I’d be impressed by a natural phenomenon that could create that rate of change, barring asteroid impact or sudden violent volcanic activity or the like. Which wouldn’t be comforting at all.

          • Ken Snider | May 5, 2021 at 2:28 am |

            I’ve been reading and paying attention to this issue for a few decades, so one thought tends to connect to another as it is all connected. Sorry about that.
            It is all related to the same subject. The one thing I’ve learned for sure is that just when I think I know something in this area, a study or several studies will come along that reshape my understanding.
            30 years ago, I thought solar panels and hydrogen would be the answer. As I have learned more, not so much.
            The climate and all its processes have far more to them than humans understand. We’ve only been studying the climate with focus for a short time.
            I suspect what we will learn in the future is far more than what we have learned so far.

            The most severe recorded temperature changes were the result of large eruptions. I have read papers that some of temperature changes at boundaries of the Roman Warming period, Dark Ages, Medieval Warming and Little Ice Age were sudden and in short periods less than a decade and sometimes oscillated up and down for several decades. There are records related to crop abundance and other writings in historical records. Going back to find those references is more effort than I will make now.

            There are also extrapolations from ice cores, mud bores and other temperature proxies that go back further, but they are not as precise about short time frames.
            For me the bottom line is there are indications, but no certain evidence of big sudden swings in the past. There is also no certain evidence that all temperature changes in the past happen gradually. There are only conclusions people who study these areas have reached. At this point their findings are often conflicting.

            To say that our current warming is “unprecedented” or is “setting records” is to assume a certainty about past climate that is unwarranted given the current state of our knowledge about the climate.
            When I see an article like the one above that expresses that certainty, my antenna go up. Little in climate science is certain or predictable at this point.
            Basing significant public policy decisions, that will be far reaching and have negative impacts on many lives in the near term, on our current limited climate knowledge strikes me as folly.

            Well, I have wandered about again. The stimulation of this conversation and your questions has my mind moving about.
            If your interested in a far-reaching weekly compilation of all things written about the climate, I recommend subscribing to the free weekly compilation from They have their point of view, but are pretty good about including articles and studies from all sides. They always link to the sources, so you can dive in as deep as you want. They have an extensive archive available.

          • It’s really not an easy conversation to have and still keep a narrow focus. I struggle mightily with the fact that most of the “climate skeptics” I interact in my daily life with are among the least skeptical people I have ever met. And for some reason this topic produces strawman arguments, since most people lack the expertise to honestly address opposing views. I have to rely on the experts and try and control my loathing for the pundits.

          • Ken Snider | May 5, 2021 at 5:21 pm |

            Loathing for the pundits is definitely something we can agree on.

  6. I confess I am joining the Patersons. I am little less skeptical. Dr X clearly knows a lot about climate science and he puts it well. I intend to read Unsettled, by Koonin, to see what I can learn there.

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