Global warming, climate change, all these things are just a dream come true for politicians. I deal with evidence and not with frightening computer models because the seeker after truth does not put his faith in any consensus. The road to the truth is long and hard, but this is the road we must follow. People who describe the unprecedented comfort and ease of modern life as a climate disaster, in my opinion have no idea what a real problem is.
A detector from the Askaryan Radio Array (ARA) near the South Pole captured 13 distinct impulsive radio bursts during a 208-day observation period in 2019 (using just one station). These signals originated from below the ice surface and have now been reanalyzed and confirmed as Askaryan radiation—coherent radio waves emitted by particle cascades in the ice.
A detector from the Askaryan Radio Array (ARA) near the South Pole captured 13 distinct impulsive radio bursts during a 208-day observation period in 2019 (using just one station). These signals originated from below the ice surface and have now been reanalyzed and confirmed as Askaryan radiation—coherent radio waves emitted by particle cascades in the ice.
The Askaryan effect (also called Askaryan radiation) is a powerful, coherent radio-frequency emission produced when an ultra-high-energy particle creates a dense electromagnetic shower in a transparent dielectric medium such as Antarctic ice, rock salt, or silica.
Physicist Gurgen Askaryan predicted it in 1962. It is now the cornerstone of radio-detection techniques for ultra-high-energy neutrinos and cosmic rays.
In 1962, physicist Gurgen Askaryan predicted that when a high-energy particle (like a cosmic-ray proton or nucleus) slams into dense matter such as ice, it triggers a shower of secondary particles. In this shower, a slight excess of negative charge builds up (electrons outnumber positrons slightly due to scattering and annihilation effects). This moving charge excess produces a brief, powerful pulse of radio waves (in the ~100 MHz to GHz range) via the Askaryan effect—essentially Cherenkov-like radiation but in radio frequencies, coherent and thus amplified at certain wavelengths.
This effect was previously observed in labs and in the atmosphere, but detecting it in situ within Antarctic ice proved technically challenging due to the need for buried antennas, low noise, and precise triggering.
The Askaryan Radio Array (ARA) embeds radio antennas deep in the ice at the South Pole. Its primary goal is hunting ultra-high-energy (UHE) cosmic neutrinos—ghostly particles that could reveal the origins of the universe’s most energetic cosmic rays. Neutrinos interact rarely, so radio detection in vast volumes of transparent ice (where radio waves travel kilometers with little attenuation) offers a scalable way to monitor huge effective volumes cheaply compared to optical detectors like IceCube.
Cosmic rays hitting the atmosphere create air showers whose cores can penetrate and interact in the upper ice layers, producing similar radio pulses. These serve as a background for neutrino searches but also a perfect calibration source. The 13 events matched predictions in:
Arrival directions
Signal shape and polarization
Spectral content
Overall rate
The statistical significance is high (~5.1 sigma; the chance of them being random background is less than 1 in 3.5 million).
This is the first experimental evidence of in-ice Askaryan radiation from cosmic rays. It validates the radio-detection technique and the detectors’ performance. Future arrays (like expansions of ARA, IceCube-Gen2’s radio component, or the Radio Neutrino Observatory in Greenland) can now confidently use this method to sift through data for the much rarer neutrino signals.
It doesn’t solve lingering mysteries from the ANITA balloon experiment (which detected anomalous upward-pointing radio pulses in 2016–2018 that didn’t fit standard models and sparked speculation about beyond-Standard-Model physics or exotic particles). Those ANITA events remain unexplained and are likely unrelated—the ARA signals here are downward/expected cosmic-ray induced and come from a buried in-ice setup.
In short, it’s a solid, exciting step forward in multi-messenger astrophysics and neutrino astronomy: the “cosmic whisper” is Askaryan radio pulses finally heard clearly in ice, opening the door wider for detecting the universe’s most elusive high-energy messengers.
Observation of In-Ice Askaryan Radiation from High-Energy Cosmic Rays
“Observation of In-Ice Askaryan Radiation from High-Energy Cosmic Rays” by the ARA Collaboration (lead author N. Alden et al.), published in Physical Review Letters 136, 151003 (2026). arXiv: 2510.21104 (submitted October 2025, with an updated HTML version in April 2026).
This is the first experimental detection of in-ice Askaryan radiation produced by high-energy cosmic ray air showers interacting directly with the Antarctic ice sheet.
Data: From a 208-day observation period in 2019 using the phased-array instrument at one station of the Askaryan Radio Array (ARA) at the South Pole.
Events: 13 impulsive radio-frequency bursts originating from below the ice surface (i.e., not from the atmosphere or surface noise).
Significance: The rate, directions, signal shapes, spectra, and polarization strongly match predictions for Askaryan emission from the dense cores of cosmic-ray-induced air showers penetrating and cascading in the ice. Background (thermal noise + surface events) is ruled out at 5.1σ significance (when including impulsivity; 3.5σ from geometry/timing alone). The observed rate is consistent with expectations (22.9 +8.2/−6.2 events per year for this setup).
For the brightest events, the angular radiation pattern even favors an extended cascade-like emitter (as expected for a shower) over a point-like source.
“We present the first experimental evidence for in-ice Askaryan radiation — coherent charge-excess radio emission — from high-energy particle cascades developing in the Antarctic ice sheet. In 208 days of data recorded with the phased-array instrument of the Askaryan Radio Array, a previous analysis has incidentally identified 13 events with impulsive radiofrequency signals originating from below the ice surface. We here present a detailed reanalysis of these events. The observed event rate, radiation arrival directions, signal shape, spectral content, and electric field polarization are consistent with in-ice Askaryan radiation from cosmic ray air shower cores impacting the ice sheet. For the brightest events, the angular radiation pattern favors an extended cascade-like emitter over a pointlike source. An origin from the geomagnetic separation of charges in cosmic ray air showers is disfavored by the arrival directions and polarization. Considering the arrival angles, timing properties, and the impulsive nature of the passing events, the event rate is inconsistent with the estimation of the combined background from thermal noise events and on-surface events at the level of 5.1σ.”
This Letter reports the first in-situ detection of Askaryan radio emission produced inside Antarctic ice by high-energy cosmic-ray air showers. It uses data from a single station (A5) of the Askaryan Radio Array (ARA) at the South Pole, collected March–November 2019.
Background & Motivation
The Askaryan effect (predicted 1962) generates coherent radio pulses (~100 MHz–1 GHz) from the net negative charge excess in particle cascades in dense dielectrics like ice.
ARA’s main goal is ultra-high-energy neutrino detection via the same mechanism, but cosmic-ray air showers provide a natural, abundant calibration source/background.
When a cosmic-ray shower core penetrates the ice surface, a compact cascade develops in the top ~5–10 m, producing downward-going Askaryan radiation detectable by buried antennas.
Data & Analysis
Instrument: Phased-array trigger on vertical-polarization (VPol) antennas at Station 5 (low threshold).
Event selection: 13 impulsive RF events in the “target zenith” window (38° ≤ θ ≤ 57°), where surface/atmospheric signals are suppressed by total internal reflection.
Events are tested for impulsivity (peak-to-average power ratio), time clustering, azimuthal uniformity, and wind-speed independence (rules out triboelectric/atmospheric noise).
Key Results
Observed rate: 22.9⁺⁸.²₋₆.² events per year — consistent with Monte Carlo predictions for ~10¹⁷ eV cosmic rays.
Signal properties perfectly match simulations of in-ice Askaryan emission:
Broadband impulsive pulses
Radial polarization
Arrival directions (Kolmogorov–Smirnov p = 0.88 with CR-shower simulations)
Brightest events: Angular radiation pattern statistically favors an extended cascade over a point source (ΔlogL > 1.5 for three events).
Geomagnetic emission (from charge separation in air showers) is strongly disfavored (KS p = 2.6 × 10⁻¹⁵).
Significance: 5.1σ (including impulsivity) or 3.5σ (geometry/timing alone) against combined background.
Implications
Validates radio detection of cosmic rays via their in-ice component — a new, complementary channel.
Critical calibration benchmark for ARA and future radio neutrino telescopes (IceCube-Gen2 radio, RNO-G, etc.).
Demonstrates that the technique works in real Antarctic ice, including signal propagation and reconstruction.
The full A5 dataset likely contains >100 similar events, enabling refined simulations and background studies ahead of first neutrino detections.
Well, it’s a very political subject and the idea that the climate is in a crisis, I don’t think that that’s actually the case. It’s much less I mean, the climate disasters and so on, I mean, they’re not really increasing at all. And, of course, the temperature has gone up a little bit, but it has not, you know, made a serious crisis that we cannot handle. So, I actually think the idea that we are in a crisis is actually not correct.
Danish astrophysicist Henrik Svensmark explains how the changes in solar activity and cosmic rays can influence cloud formation and therefore our climate on Earth. Title above is link to podcast video at Freedom Research. Below is the transcript lightly edited with my bolds and added images. FR refers to Freedom Research interviewer Hannes Sarv, and HS refers to Henrik Svensmark.
Hello, welcome. This is the Freedom Research Podcast and my name is Hannes Sarv. My guest today is a researcher from Denmark, an astrophysicist, Henrik Svensmark. He’s well known for his research on the relationship between cosmic rays and Earth’s climate. He has proposed that the variations in cosmic radiation influence cloud formation and consequently global temperature and biodiversity. Of course, we’re going to talk about climate change, cosmic rays and supernovas and how they affect Earth’s climate and biodiversity well here on Earth. So first of all, thank you, Henrik, for taking the time for this interview.
Firstly, I would actually like to ask a question. Simple, simple question, which can be puzzling, at least to a lot of people. I mean, if you’re being told that you’re living in a constant climate crisis, then probably most of the people probably fear it or they might get afraid. So if someone says to you that today there is a climate crisis. What is your answer to that?
HS: Well, it’s a very political subject and the idea that the climate is in a crisis, I don’t think that that’s actually the case. It’s much less I mean, the climate disasters and so on, I mean, they’re not really increasing at all. And, of course, the temperature has gone up a little bit, but it has not, you know, made a serious crisis that we cannot handle. So, I actually think the idea that we are in a crisis is actually not correct.
FR: So you think, probably It depends on where you live, right? If the temperature goes up, it gets warmer and well, as I have understood most of the places or the larger part of the population actually benefits from higher temperatures. What is your take?
HS: Certainly, there are places where you actually benefit from it. And in many cases, it’s not because it actually gets warmer. It’s more like it’s climate’s getting milder, meaning that it’s the colder temperatures, you know, at night and in the winter that goes slightly up, which is actually a good thing. I mean, here in Denmark, we haven’t had very severe winters for a long time. which is also good. It’s good for the economy. It’s good for many things because a cold climate is much, much worse than a warmer climate. I think that, I mean, you also know that You also talk about people, you can have people dying from warm weather, but we know that it’s mainly cold weather that is the real killer of people. I think there’s almost a factor of 10 in difference. So slightly milder weather is not a problem. I mean, it’s certainly not a disaster.
FR:This is kind of puzzling also to many people, if they’re being told that the planet is going to be inhabitable. Then there’s talk of sea level rise and all those other apocalyptic things that make good movies. But the actual truth there is at least a bit more complex, would you say?
HS: Yes, there’s been so many claims. I think also people should get tired of all the predictions that are wrong. I mean, that there would be no ice in the Arctic and Greenland is melting and so on. And, you know, the islands in the Pacific should be subsiding because of the rising sea levels. And it’s not really happening, any of these things. And all these predictions, which I mean, it gets everybody’s attention, of course, because we are sort of prone to react when we hear about disasters, or coming disasters. They are not really happening fortunately. I mean, it’s actually a good thing that it’s actually not occurring.
FR: So when we look at a longer time frame, it should be brought out that there have been many such crises that have threatened all life and human life. So can you just maybe make a comparison here to today’s climate?
HS: When we talk about global warming, we say that the temperature might have got up by one degree or something like that. But if we look at geological time scales, the climate changes are much, much more severe. I mean, you have periods where you have glaciations, that is, ice almost down to the equator, and perhaps even most of the Earth is covered by ice, and you have periods where there’s no ice caps at all, and the temperature is much, much higher. I mean, you have had… Beobab trees in Antarctica, and you had alligators at the latitude of Greenland.
So you have had much, much warmer, at least 10 degrees warmer climate back in time. So if we look at geological timescales, we have had enormous changes in climate. And of course, all of this is completely natural. And the question is, why did we have such big climate changes? And this is some of my work trying to understand why we have such large climate changes even back in time.
FR: So let’s talk about that. This is interesting that we’ve been told that the climate change today is anthropogenic. So let’s talk about your perspective on that and what does your research show?
HS: There’s no doubt that CO2 is a greenhouse gas and it has some effect on the temperature. The issue has to do with climate sensitivity. How big is the climate sensitivity? And it turns out that it’s probably around one degree if you double CO2. So, it’s a relatively benign effect of CO2. So, I’ve been working trying to understand why there are climate changes. When you look at climate changes, for instance, over the last 10,000 years, you can actually see that if you compare the climate changes with changes in solar activity, you actually find a very nice correlation.
Fig. (3). (Color online) Upper panel: Global record G7 (grey), running 31 year average of G7 (blue), sine representation of G7 with three sine functions of the periods 1003, 463, and 188 years (green), with four sine functions including the period ~60 years (red), continued to AD 2200. The parameters of the sine functions are given in Table 3. The Pearson correlation between the 31 year running average of G7 and the three-sine representation (green) is 0.84, for the four-sine representation (red) 0.85. Lower panel: G7 (grey) together with the sine functions of 1003, 463, and 188 – year periods continued until AD 2200 (equal sine amplitudes for clarity) Source: Ludecke & Weiss 2019
There are so many studies that show that you had, for instance, the Little Ice Age And you have the medieval warm period. And the medieval warm period is when you had a high solar activity. The little ice age is when the solar activity was low. And the question is, why should there be such a correlation? How can the solar activity actually affect climate? And the simplest idea that has been put forward was that the output from the sun in the form of radiation, I mean the sunlight, that is changing. But it turns out that these changes are probably too small to explain what the climate changes you’re seeing.
So something else is going on, something is amplifying the solar activity and the idea that I came up with this now, actually 30 years ago, was that maybe solar activity is somehow regulating the Earth’s cloud cover. And initially, I took data from satellites that looked at the Earth’s cloud cover, and I looked at it over a solar cycle that’s about 11 years and compared the changes in the solar cycle with changes in the Earth’s cloud cover. There seems to be a correlation between the two. So one can say that the idea, I mean, it looked as if it was something worth pursuing. But of course, it was just a correlation at that time.
Cosmic rays interacting with the Earth’s atmosphere producing ions that helps turn small aerosols into cloud condensation nuclei — seeds on which liquid water droplets form to make clouds. A proton with energy of 100 GeV interact at the top of the atmosphere and produces a cascade of secondary particles who ionize molecules when traveling through the air. One 100 GeV proton hits every m2 at the top of the atmosphere every second.
And I couldn’t say why there should be such a connection. So the general idea has to do with the formation of clouds. How are you actually forming clouds? And it turns out it’s the ionization that is happening in the atmosphere. There’s typically about a thousand ions per cubic centimeter. So if you have a small cubic centimeter, you might have on the order of a thousand ions per cubic centimeter. And these ions are in general mainly produced because of very energetic particles that come from the Milky Way that is outside our solar system.
And they move in through the solar wind and then enter into the top of the atmosphere, where they then ionize the atmosphere. And the story is these small ions help stabilizing small molecular clusters. So, you get what we call aerosols. These very small aerosols, which then grow up to a certain size. In order to make a cloud droplet, you have to have some kind of surface on which water vapor can condense. These small aerosols are actually providing these surfaces.
The idea is that if you have more cosmic rays coming into the atmosphere, you’re producing more of the small aerosols. They grow to become what we call cloud condensation nuclei, so they can affect the clouds, so water waves can condense and become cloud droplets. So if you have more cloud droplets, you have a more white cloud. And a more white cloud actually reflects the sunlight out to space again. That is, of course, extremely important for the Earth’s energy balance. So that is the main idea behind the theory that I have been working on.
FR: Okay. And so if there is more clouds and reflect the sunlight back to space, I’m just gonna ask, I’m a lay person, not a scientist. Maybe I’m not, you know, a bit stupid question in that sense. But if it reflects more sunlight out, then well, logically, we get the cooler climate, right?
HS: Yes, exactly. Observations are one of the ways we can verify that it works. So, on relatively rare occasions, there are some explosions at the sun. They’re called coronal mass ejections. It’s when the magnetic field lines sort of open up and the sun is throwing out a large magnetic plasma. And this magnetic plasma works more or less like an umbrella or a shield against the cosmic rays. So, within a week, the cosmic rays are dropping, and they can drop maybe up to 30% or something like that. And that is like a natural experiment with the whole Earth.
And so you can actually then see if anything is happening with the Earth’s cloud cover. And this is something that we have investigated. So, for instance, we can also look at the aerosols that are produced after these events, and we can see that there is a big drop in the aerosols. And then we see a drop in the clouds following these events. And it’s not just the cloud fraction, it’s also the optical properties of clouds. So we can actually see changes in the cloud’s microphysics under these events.
So in some sense, we see the whole chain from the explosive events and the sun to changes in the cosmic rays to changes in the aerosols and then changes in the clouds. And there is a slight delay on a few days in the reaction. That’s simply because it takes about five days for the small aerosols to grow to become cloud condensation nuclei. So everything seems to be fitting very beautifully with respect to this idea.
FR: Okay. But, well, how frequently does it happen, what’s the correlation here? I mean, how frequently it happens to change the climate in that sense?
HS: I talked about this event with the explosions at the sun, which is something that happens during a week. So, it’s too much too short to affect climate. But the solar activity modulates the cosmic rays. And that’s simply because the solar activity translates into changes in the solar wind. And the solar wind is covering the whole solar system and all the planets. That works like it’s a magnetic shield that screens against the cosmic rays.
So, when the solar activity is high, you can say that it’s screening better against the cosmic rays. That means you get fewer cosmic rays into the atmosphere. So solar activity can regulate the amount of cosmic rays that comes into the atmosphere. So that regulates in the cloud cover. And we can then estimate, I mean, how much it changes the cloud cover during an 11-year cycle.
And from that, we can calculate what would be the effect on the temperature in the oceans. And there you actually see that we get about on the order of one to one and a half watt per square meter more energy in when you have a solar maximum than when you have a solar minimum.
And you can actually observe that in the ocean’s temperatures. You can see that in the heat content of the ocean. And you can even see it in the volume, because the heat goes in and out of the ocean. So when you get heat into the ocean, it expands a little bit. So in the sea level, you can actually see an 11-year cycle in the sea level. And all of this, you can quantify how much energy goes in and out of the ocean.
And it fits very beautifully with what you expect from changes in the cloud cover over a solar cycle. And it’s interesting that the solar irradiance is almost a factor of 10 too small to explain it. So there is some kind of amplification mechanism. And the idea is that it’s clouds that are responsible for this. And this is something that you should takeway with respect to the ocean temperatures and the energy that goes in and out of the ocean he has been looking at.
FR: Okay. But how does it fit this idea? How does it fit the historical records?
Figure 4. The millennial solar-climate cycle over the past 2000 years. The anomaly in 14C production levels (black curve), a proxy for solar activity, is compared to iceberg activity in the North Atlantic (dashed blue curve), a climate proxy. The pink sine curve shows the millennial frequency. It defines two warm and two cold periods, supported by a large amount of evidence, some of which are represented by red and blue bars (see main text). Source: Javier Vinos
HS: Well,If you look at solar activity going back in time, we talked about the Little Ice Age, which is from around 1300 to 1850. And then you had the medieval warm period for 900 until maybe 1200. that these changes, they fit very beautifully with changes in cosmic rays. So when it’s cold, you have more cosmic rays coming in. And when it’s warm, you have less cosmic rays entering into the atmosphere. And we know these changes in cosmic rays because when cosmic rays enter the atmosphere, They are actually producing new elements like carbon-14, which is a radioactive form of carbon. It’s slightly heavier than carbon-12.
I guess many people know that you can use carbon-14 for dating things. But this carbon becomes CO2, the heavy form from carbon, and it goes into trees. And then you can look at the annual rings of the tree rings and measure how much carbon-14 you have relative to carbon-12. And you can then measure that for all the tree rings going back in time and you can actually reproduce solar activity almost 20,000 years back in time. And if you look at these changes and you compare with how climate has been changing over that period, there is beautiful correlations again.
So it is near certain that there is a connection between solar activity and climate. And you can also quantify some of these changes and they are relatively big and it seems as if that, you know, changes in clouds is a very good candidate for explaining this. And when we look about the last 10,000 years, then the modulation of the cosmic rays, it’s caused by solar activity.
FR: Okay. Let me just ask you about those cosmic rays again. You did say, but again, I’m not that bright in your field. You did say it comes from Milky Way. Okay. Why does it come from there? Or what is it? What sends it here?
HS: Cosmic rays are very energetic particles. It’s mainly atomic nuclear, 90% is protons. So that’s the core of the hydrogen atom. So the energetic particles that we are interested in are mainly produced in what we call supernova. And a supernova, the case that we are interested in, is when you have a massive star that is maybe eight times or more massive than the sun. It only lives a relatively short period of time, you know, from maybe three million years to 40 million years.
So it’s a large star and it’s very heavy, and then in the process of burning, it burns so fast and it ends its life in a very, very violent explosion, which is called a supernova. And this supernova, when it explodes, it produces a shock front that is moving out from where the star was located. And this shock front, it works as, you can call it, a cosmic accelerator.
So it accelerates particles that move back and forth over this shock front and move them to extremely high energies. And the energies that you can obtain by this process is much higher than we can produce in any accelerator here on Earth artificially. And these particles, they are then moving in the interstellar space in the Milky Way.
And they are moving in the magnetic fields that are in between stars. So, they are sort of moving like what we call diffusion. They are sort of randomly moving around, being bent by the magnetic fields. And then some of them will be outside, you know, arrive outside our solar system.
We have the heliosphere and then they move in and they feel the magnetic field from the sun. And some of them will then enter into the top of the atmosphere. And then you have maybe one proton that comes in with extremely high energy. And then it works a little bit like billiard ball where you have one particle hitting the molecules or the atoms in the atmosphere and it makes a shower, sort of a cascade of particles that goes down through the atmosphere. And these particles are called secondary particles. And so you can have one particle coming in that becomes millions and even billions of particles that move down through the atmosphere.
These particles are completely invisible to our naked eye. While we are sitting here, we are penetrated by these secondary particles that go through my body and your body all the time. And so every 24 hours, maybe 20 million particles will go through your body and you don’t really experience this. This is something that has happened since the formation of our galaxy. And of course, here on Earth, we have been showered with these particles for four and a half million years.
FR: Well, since you can explain past events with solar activity and how many cosmic rays are coming towards Earth, probably you can basically model what will happen as well, right? So, I mean, the question is, where are we now in terms of changing climate? Because I’ve also talked, for example, to Professor Zharkova. She said to me that we are entering another ice age soon.
HS: There’s no doubt that we will get an ice age. We have had a number of ice ages back in time. I don’t know if you’re talking about a real ice age or you’re talking about a little ice age, which is just a colder period.
FR: She was talking about the little ice age. I understood.
HS: So, a little ice age. I know there are some predictions that the solar activity will go down, and we might get a slightly colder period. I’m not sure it will be a little ice age, but it’s not something that I have looked at in any details. At the same time, of course we have had some heating from the CO2 increase in CO2. And then solar activity would then go the opposite way if the solar activity goes down. The problem with these predictions is that it’s extremely difficult to predict solar activity in the future.
Source: spaceweatherlive
We can’t even predict the next solar cycle, whether it’s going to be high or low. There are some really amazing examples where this last solar cycle was predicted and the predictions were sort of all over the place. So it is really difficult to know because we don’t understand solar activity in a detail where we can predict what the next solar cycle will be. But that might come at some point. So something special has to happen. I think if we’re going to have a real cold period where the temperature drops by one or two degrees, that would be very special. I’m not sure that we’re going to see that, but I know that Zharkova is predicting that.
FR: Okay, yes. Anyhow, the thing is that still almost, well, all of it indicates that climate change is, there are some other factors than humans leading the climate change. But what is your opinion? What is the role of us on climate?
HS: Oh, the anthropogenic CO2? Yeah. So, as I said, it is a greenhouse gas. So, you can see if you look at the outgoing long-wave spectrum, you can actually see there is a drop in the outgoing long-wave spectrum, which has to do with CO2, which means that it is a greenhouse gas. The question is, how important is it? Is it so important that it’s changing temperature, you know, in a dramatic way? And I think there’s so much research now that seems to indicate that the climate sensitivity is on the order of, you know, one, maybe a little more than one degree for a doubling of CO2.
And that is much smaller than what you get from these climate models, which gives you between three and four degrees of that order, but at least a few times larger than what you get just from CO2 alone. Because in the climate models, the reason they get between three and four degrees is because they assume that it would be less cloudy, for instance, in the future climate. So you might have one degree from CO2, but then you get on the order of one or two degrees extra from what we call positive feedbacks. And that is something like more water vapour in the atmosphere or less clouds in a future climate.
And the problem is that water vapour and clouds are really the most uncertain thing about any prediction of climate. Clouds and aerosols are really what makes climate predictions so extremely difficult. And it’s because it’s all happening at length scales that are much, much smaller than what you can resolve in climate models. You have to remember that you have maybe, you know, 50 to 100 kilometers between two grid points in a global numerical model.
And that means that, you know, if we just take Denmark, you have maybe one or two grid points over Denmark. And in each of these grid points, you have to determine, you know, what are the clouds actually just from temperature, humidity and pressure. So you have to do some kind of a parameterization of all the physics. So you’re not resolving clouds at all, but you are trying to use, you know, temperature and pressure to say what will the cloud look like for these variables. And this is basically impossible. I mean, it’s pure guesswork.
FR: So what do you think about those climate models? I mean, are they useful then at all?
HS: Of course, they’re useful for some things, but they’re not useful to say if the climate is going up by some fractions of degrees. And I don’t think you can use them for predicting future climate.
FR: But this is what they are used for, isn’t it?
HS: Yes, but I think also that there are some kind of a consensus that climate models are not doing well, I mean, that they have real problems in predicting and saying what is going to happen in the future. So, they are not a crystal ball that can tell us about the future with very much accuracy. Well, it depends on how you ask the questions, of course, but I think just recently there were some statements from people who are doing these models saying that they were running too warm.
So they are, you know, exaggerating the warmth. And I think in one of them, there was because they updated their cloud scheme. So they changed the perameters of clouds. And all of a sudden, it was running slightly warmer than before. So again, it just points to the severe problem of clouds. I should also say that if you take out clouds of the models, then the model results start agreeing with each other. Whereas when you have all the clouds in the models, then you get very different results from various models. I mean, it’s not like in particle physics where you have a standard model that you can use.
I mean, here you have a whole ensemble of the different models and they all give slightly different results. And then you make an ensemble average of all these models and try to say that that is the future. It’s, of course, not really satisfying.
FR: Of course. So what do you think about the reports that the UN IPCC puts forward, the scientific reports? Are they something that are, you know, accurate?
HS: I looked at it with respect to the things that I’m doing. One of the things that, you know, struck me was that if you look at the effect of the sun over the last hundred years, there is no effect whatsoever. I mean, it is so small that, I mean, they’re saying essentially that there’s no effect of changes in solar activity. really a shame in the sense that I mean, for instance, we see in the present climate that we’ve had over the last 50 years, you can see solar cycle variations in the ocean heat content and so on, which we talked about just before.
So the solar activity seems to be 10 times larger than what you get from solar irradiance. And in The reason that they get such a small effect of the sun is because they are only considering changes in solar irradiance, which has to do with the solar constant. The solar constant is changing, you know, about one tenth of one percent. So that is so, so small that it does not have any effect on climate. However, the changes in… In clouds, if we take the ideas that I have been working with Nir Shaviv we will get that over the last century, over 120 years, I think at least one watt per square meter has entered because of solar activity.
Solar activity does not seem to have been completely negative as well. over the last 10 years. So when we think about how the issue is approached, the issue of climate change in society now, well now there’s the new administration in the United States that actually approaches it somewhat different, but in the EU, for example, Mrs. von der Leyen said that she’s still determined to go to net zero and so on.
So what I mean here is the somewhat hysterical tone that this issue is approached with and also the predictions of doom. So my question is if it’s the same in the academia or not. I mean scientists are in my opinion, at least, they seem very rational and fact-based. So, is it somewhat different in the inside, I mean, if you talk to your peers?
HS: I usually say that climate science is not normal science. There’s so much politics involved, even in academia. There is a sort of self-censorship. It’s a bad career move to go against the idea that CO2 is the main driver or to say what i’m saying right now so it’s not good for your career to to do that it has implications, I mean first of all it’s the only research that is being financed that can be done, if you don’t get a grant or anything, you cannot do any research.
And that’s also why I think many people will not rock the boat, because it’s a good way of getting financing for the research that you want to do. However, if you try to do things which I have done, which is perceived as controversial and not according to the general ideas, it becomes very, very difficult to obtain funding and to survive in this system. And people are very emotional about this because some people think that they are trying to save the world from a disaster. And, you know they think everybody else has really bad motives, maybe hidden motives, your multinational oil companies or something like that.
So it’s really difficult to be in opposition to these ideas. So that it’s very, very difficult for me to obtain any funding. Some people are very upset, you know, if you have been invited for giving a talk and some people find out who you are. and so on. So there’s many, many strange things happening.
FR: It’s really happening, right? I mean, it has happened to you that you’re invited to give a talk to talk about your research and there are activists who are coming to cancel you. Did I understand correctly?
Antifa thugs outside Munich Conference Center at 2019 Climate Meeting.
HS: Yes. I’ve also given talks in Germany, where the whole conference had to have police protection because of the demonstrators that tried to storm the place. Another time, on the building, they printed that we were Nazis and they put glue in the locks and so on. Yes, so one couldn’t get in. I mean, it’s just sometimes it’s very, very, very strange how emotional it is. And there’s nothing rational about it because it’s not something that you can have a discussion about. I mean, you also heard people saying that, you know, the science has been done. Now it’s only action that is needed.
FR: Yes, yes. Well, it’s being parroted all the time. I don’t know, is it 100% already or last time I checked it was 99% of climate scientists agree on something.
HS: But all of these things are simply propaganda of some kind. It has no sort of basis in reality. It’s just some talking points that are being spread out. And some people believe them and other people know that they’re not entirely correct. And that’s how it is.
But the good thing is that I tried to survive in this system. Then I started to look at very, very long timescales. And I think, I mean, maybe we should I should tell you just a few words about that, because I think it’s a completely fascinating result that has come out. Absolutely.
So, we talked about these supernovas that goes off, and they are producing the cosmic rays. So, you can say supernovas are the source of cosmic rays. And the interesting thing is that our solar system it is actually moving around the Milky Way galaxy. So we are in a spiral galaxy, so it’s like a flat thing. And we are moving around the center of the galaxy, the whole solar system, within 240 million years or 230 million years it takes. Our Milky Way is a spiral galaxy. And in these spiral arms, that’s actually where you have a lot of star formation. And star formation is where you also produce the large, heavy stars that explode.
Cosmic radiation and temperature through Phanerozoic according to Nir Shaviv and Jan Veizer. Blue columns refer to Milky Way Spiral arms.
So that means that when the solar system goes through a spiral arm, it actually in an area with much higher cosmic rays, Whereas when you are in between spiral arms, you have much lower. And the changes are not 10, 20% like we have from solar activity.
Now we are talking about several hundred percent of changes in the cosmic rays. So you can say that this is a completely independent way of testing the cosmic ray climate mechanism. Because if these changes in cosmic rays are important for climate, as we see in the present time, maybe they should also be important when we go back in time. It’s something that Nir Shviv actually looked at around 2001.
And what you find is that when you are in a spiral arm, it tends to be extremely cold on Earth. So the glaciations that we have had on Earth on cold periods fit beautifully when we were in spiral arms. And when we were in between the spiral arms, it was extremely warm. The temperature changes and the climate changes we are talking about are now, you know, from what we call an ice house, that is the glaciation, very severe glaciations, that is the large ice sheets on the Earth, to where they are completely melted and, you know, the sea level has gone up maybe by 100 meters or something like that. So it’s enormous changes.
What I looked for was to see if it has implications for life on Earth. And it turns out that you can actually indirectly look at how big the biomass has been at certain times in the ocean. And that is because you can look at organic material. So when you have the ocean and you have organic material, some of the dead material falls down at the bottom. And you can actually say something about the fraction of organic carbon relative to inorganic carbon in sediments.
So, when you have sedimented mountains, you can go and measure this ratio of organic carbon to inorganic carbon. And it says something about the fraction of organic material that has been buried in sediments. And it turns out when you look at this fraction as a function of time, it fits beautifully with changes in reconstructed changes in supernovae.
And you can actually see it in fairly high details over the last 500 million years. And it turns out that you can actually extend it. So from geology, you have this fraction of organic material almost four and a half billion years back in time. And even here, it fits beautifully with the changes in the cosmic rays that have happened over the whole history of the Earth. It’s completely astounding that you have this correlation over four and a half billion years. So it says that the biomass seems to have been following things which are thousands of light years away from our solar system.
So this star formation has actually influenced the conditions for life. And it’s even more interesting because when you bury organic material, the organic material is made because of photosynthesis. And photosynthesis, that is, you know, the algaes, the green algaes produce oxygen. So you have CO2 and water and sunlight that becomes, you know, sugar and oxygen. But in order for the reaction not to go back again, so the oxygen becomes CO2, you actually have to take the organic material and then have the oxygen and you bury the organic material in the sediments.
That’s the way you get the oxygen. So, these variations in the organic material, these variations, they are actually also the production of oxygen that we have had over the whole history of the Earth. So, supernovas have therefore indirectly produced or been responsible for changing the oxygen at Earth and all complex life. I mean, in order to get complex life, we need oxygen. So, it’s really been a very important part. So, it seems to say that the Earth is really a part of an ecosystem, you know, where it really involves most of the galaxy. So here we see that it fits beautifully with the changes in cosmic rays or supernova frequency over most of the history of the Earth.
Source: Phanerozoic_Biodiversity.png Author: SVG version by Albert Mestre
I did another thing where I looked at the diversity of life, and just to cut the thing relatively short, it turns out that there’s a beautiful signal of the supernova frequency, even in the frequency, in the diversity of life, where you can see a very, very beautiful correlation over the last 500 million years. So it suggests that somehow the changes in the supernova change the climate. And by changing the climate, if it’s colder, you have a larger temperature difference between equator and polar regions.
That means you have stronger winds. And if the wind is stronger, then you have more mixing in the oceans. And what it is mixing is the nutrients that life actually needs. I mean, a lot of the nutrients, they run out from rivers because of rain. And you have, you know, phosphorus and iron and oxygen. and other important elements for life. But they are then transported so life can uptake these nutrients. And the idea is that when you have more nutrients, then you can also have a higher diversity and you also get the higher biomass and you get more sediments. So everything seems to be connected in that way. I hope this was not too complicated.
FR: Well, I mean, yes, I think it wasn’t too complicated, but it’s really interesting to actually hear about the research, yes, and to think about the connections that you pointed out there. So, the only thing I would like to ask here is that, so it’s a hypothesis, of course, and again, how… how it is welcomed in your circles? I mean, is there any discussion about it or how it is approached?
HS: I think in geology and geologists, there’s a lot of geologists that really like it because many of them, they have seen how climate is changing over these long timescales and, you know, some of them, they know that CO2 does not appear to be the driver of climate changes on these long timescales. But I should also say that even in geology, there are people who are promoting that everything should be CO2, that CO2 is also driving climate on these very long timescales. But there are many places where it simply does not fit. So I don’t think that… I don’t think it’s a good theory.
I mean, you typically hear about, for instance, having extremely high CO2 levels at the same time that you had an ice age. And there are some problems also within the last 30 million years where CO2 actually dropped a lot. There are periods where temperature actually goes up and so you don’t have this correlation over many million years and some of it is called a climate paradox. There are some problems.
FR: Yes, of course, of course. Yes. So, I mean, it has been really nice talking to you, but I can see that our time for today is almost running out. I mean, thank you really for this interesting conversations and for the insights and for talking about your research in detail. I hope my audience also listens and can hear some, well, good ideas, but they’re not only ideas because, well, this is what science actually must look like, ask questions and try to find answers, correct?
Many viewers of Climate: The Movie have asked for more information on the topics discussed. In response, I selected the following 70 key statements from the movie and provide references and context for the statements here. Sometimes the statements are slightly paraphrased from what was said for brevity. The statements are listed in the same order as they appear in the movie. The references, illustrations, and links below are my attempt to clarify the statements, provide context, and support the idea behind the phrase or sentence.
I received help from Dr. Willie Soon and Marty Cornell in building this bibliography. My thanks to both.
These “27 estimates are a thin basis for drawing definitive conclusions about the total welfare impacts of climate change. Moreover, the 11 estimates for warming of 2.5 C indicate that researchers disagree on the sign of the net impact: 3 estimates are positive and 8 are negative. Thus it is unclear whether climate change will lead to a net welfare gain or loss.”Tol, 2018
Lomborg, B. (2020, July). Welfare in the 21st century: Increasing development, reducing inequality, the impact of climate change, and the cost of climate policies,. Technological Forecasting and Social Change, 156. doi:10.1016/j.techfore.2020.119981
Tol, R. (2023). Costs and benefits of the Paris Climate Targets. Climate Change Economics, 14(4). doi:10.1142/S2010007823400031
Tol, R. S. (2018). The Economic Impacts of Climate Change. Review of Environmental Economics and Policy, 12(1), 4-25. doi:10.1093/reep/rex027
Skepticism is career suicide and might be criminalized.
Unsettled, What Climate Science tells us, what it doesn’t, and why it matters, by Steven Koonin.
Climate proxies
A good overview of climate proxies:
Patalano, R., & Roberts, P. (2021). Climate proxies. In D. T. Potts, & E. Harkness, The Encyclopedia of Ancient History. John Wiley & Sons. doi:10.1002/9781119399919.eahaa00609
For a discussion of many of the best global temperature proxies that cover the past 12,000 years see Climate Catastrophe! Science or Science Fiction?, 2018, pp. 95-107.
May, A. (2018). Climate Catastrophe! Science or Science Fiction? American Freedom Publications LLC.
Temperature for the past 500 million years
Scotese, C., Song, H., Mills, B. J., & Meer, D. v. (2021, January ). Invited Review: Phanerozoic Paleotemperatures: The Earth’s Changing Climate during the Last 540 Million Years. Earth-Science Reviews.
Figure 1. Scotese’s reconstruction of the past 125 million years. Major climatic changes are identified, as well as the IPCC projected anthropogenic global warming (PAW). (Scotese, Song, Mills, & Meer, 2021). Notice the PAW has recently (geologically speaking) been exceeded, it is not unusual.
When was the Earth as cold as now?
As can be seen in figure 2, temperatures have not been as cold as today for over 250 million years. Figure 2 is by the Smithsonian and from NOAA’s climate.gov website.
Figure 2. A reconstruction of Phanerozoic (past 540 million years) temperatures by Scott Wing, Brian Huber, and Chris Scotese at the Smithsonian.
Late Cenozoic Ice Age
Figure 3. The most recent 420,000 years of the 2.5 million year Late Cenozoic Ice Age as seen in Antarctic ice core data collected by Petit, et al, 1999. The CO2 is in parts per million atmospheric concentration and the temperatures are anomalies from the present. Plot from Watts and Pacnik, 2012.
The Late Cenozoic Ice Age (the past 2.6 million years) is characterized by a series of glacial advances (colder periods) and glacial retreats (warmer periods) that are about 100,000 years apart. We are currently in a period of glacial retreat, also called an “interglacial.” Our interglacial is named the “Holocene” and is the most recent 12,000 years. Notice the changes in CO2 (in red) tend to follow the changes the temperature (in blue), suggesting that CO2 did not cause the temperature change.
Holocene warm period or the “Holocene Climatic Optimum.”
Figure 4. The Holocene, with its major periods identified.
The two temperature proxies shown are from the Indonesian Makassar Strait and from Greenland. While the Makassar Strait is technically in the Southern Hemisphere, the 500-meter water there flows from the Northern Hemisphere and represents sea-surface temperatures in the North Pacific. Thus, the proxies represent the Northern Hemisphere, but they are 9,500 miles apart. The Northern Hemisphere is where the largest temperature changes occur. The Holocene Climatic Optimum is about 3.6°C warmer at these two locations than the Little Ice Age, also known as the “pre-industrial.” The source of the figure and more explanation is here.
There has been an attempt to claim that the Holocene Climatic Optimum was actually colder than today by Bova, et al. (2021), but the paper has drawn two serious criticisms (see Laepple, et al., 2022 and Zhang & Chen, 2021) and undergone a major revision.
Bova, S., Rosenthal, Y., & Liu, Z. (2021). Seasonal origin of the thermal maxima at the Holocene and the last interglacial. Nature, 589, 548-553. doi:10.1038/s41586-020-03155-x
Laepple, T., Shakun, J., He, F., & Marcott, S. (2022). Concerns of assuming linearity in the reconstruction of thermal maxima. Nature, 607. doi:10.1038/s41586-022-04831-w
Zhang, X., & Chen, F. (2021). Non-trivial role of internal climate feedback on interglacial temperature evolution. Nature, 600. doi:10.1038/s41586-021-03930-4
Holocene Climatic Optimum and the beginning of civilization
Figure 5. An overview of the development of human civilization over the past 18,000 years and its relationship to major climate changes. To download the full resolution version click here. Major events in the development of human civilization are noted, both Greenland and Antarctic ice core temperatures are plotted. Source.
Also see these interesting articles on the Little Ice Age/pre-industrial by Paul Homewood, Geoffrey Parker, and Soon et al.
Soon, W., Baliunas, S., Idso, C., Idso, S., & Legates, D. (2003b). Reconstructing Climatic and Environmental Changes of the Past 1000 years: A Reappraisal. Energy and Environment, 14(2&3).
Roman Warm Period
A brief overview of the evidence for the Roman Warm Period in Europe, with a bibliography, can be seen at CO2science.org here. More information and references are given here. The topic is also covered by Soon, et al.:
Soon, W., Baliunas, S., Idso, C., Idso, S., & Legates, D. (2003b). Reconstructing Climatic and Environmental Changes of the Past 1000 years: A Reappraisal. Energy and Environment, 14(2&3). Retrieved from https://journals.sagepub.com/doi/abs/10.1260/095830503765184619
Central England Temperature Record
The Central England Temperature record is now maintained by the Hadley Centre. It can be viewed and downloaded here. A discussion of the climatic significance of the record is given in Baliunas, et al.
Baliunas, S., Frick, P., Sokoloff, D., & Soon, W. (1997). Time scales and trends in the central England temperature data (1659–1990): A wavelet analysis. Geophysical Research Letters, 24(11), 1351-1354. doi:10.1029/97GL01184
New York Central Park temperature record
The New York Central Park temperature record can be seen and downloaded here.
1.5°C of warming will not lead to the end of man.
The potential impact of the mild rate of warming we are experiencing has been exaggerated.
Tol, R. (2023). Costs and benefits of the Paris Climate Targets. Climate Change Economics, 14(4). doi:10.1142/S2010007823400031
Nordhaus, W. (2018). Climate change: The Ultimate Challenge for Economics. Nobel Prize Lecture.
Tol, R. S. (2018). The Economic Impacts of Climate Change. Review of Environmental Economics and Policy, 12(1), 4-25. doi:10.1093/reep/rex027
The 1.5 and 2°C warming limits are arbitrary as discussed here.
Urban Heat Island Effect and Urban vs. Rural weather stations
The best and most authoritative source for the Urban Heat Island Effect is Soon, et al., 2023, here.
Soon, W., Connolly, R., Connolly, M., Akasofu, S. I., Baliunas, S., Berglund, J., . . . al., e. (2023). The Detection and Attribution of Northern Hemisphere Land Surface Warming (1850–2018) in Terms of Human and Natural Factors: Challenges of Inadequate Data. Climate, 11(9). doi:10.3390/cli11090179
Scafetta, N. (2021, January 17). Detection of non‐climatic biases in land surface temperature records by comparing climatic data and their model simulations. Climate Dynamics. Retrieved from https://doi.org/10.1007/s00382-021-05626-x
Land vs. Ocean temperatures.
Reid, 1991 and Connolly, et al., 2021 have noted that while surface air temperatures do not correlate very well with solar activity, sea surface temperatures do.
Connolly et al., R. (2021). How much has the Sun influenced Northern Hemisphere temperature trends? Research in Astronomy and Astrophysics, 21(6). doi:10.1088/1674-4527/21/6/131
Connolly et al., R. (2023). Challenges in Detection and Attribution of Northern Hemisphere Surface Temperature Trends since 1850 Research in Astronomy and Astrophysics, 23(10). doi: 10.1088/1674-4527/acf18e
Reid, G. (1991). Solar Total Irradiance Variations and the Global Sea Surface record. J Geophysical Research, 96(D2), 2835-2844.
Tree Ring temperatures
Tree ring proxy temperatures have advantages and disadvantages. They are well-dated at an annual resolution, but they are also sensitive to CO2 concentration, precipitation, and growing season length. This limits their accuracy as a proxy thermometer since they have to be calibrated to the instrumental record during the industrial revolution and a period of global warming.
The sensitivity to CO2 concentration can be a problem. When CO2 is relatively high, as it is today, trees use less water per pound of growth and are more tolerant of drought than in the past which causes a divergence in the tree ring to temperature relationship in the second half of the twentieth century. This divergence corrupts the temperature/tree ring correlation function used for the past (Briffa, Jones, Schweingruber, & Osborn, 1998).
Briffa, K., Schweingruber, F., Jones, P., Osborn, T., & Vaganov, E. (1998b). Reduced Sensitivity of recent tree-growth to temperature at high latitudes. Nature, 678-682. Retrieved from https://www.nature.com/articles/35596
Other problems with tree rings as temperature proxies, especially combining them into one temperature record are discussed by Stephen McIntyre here.
The notorious “Hockey Stick” tree ring reconstruction of Northern Hemisphere temperatures by Michael Mann, et al. is thoroughly discussed in the Hockey Stick Illusion by Andrew Montford and in several blog posts and papers by Steve McIntyre and Ross McKitrick:
Mann, M. E., Bradley, R. S., & Hughes, M. K. (1998). Global-scale temperature patterns and climate forcing over the past six centuries. Nature, 392, 779-787. Retrieved from https://www.nature.com/articles/33859
McIntyre, S., & McKitrick, R. (2003, November 1). Corrections to the Mann et. al. (1998) Proxy Data Base and Northern Hemispheric Average Temperature Series. Energy and Environment. Retrieved from https://journals.sagepub.com/doi/abs/10.1260/095830503322793632
Montford, A. (2010). The Hockey Stick Illusion. Stacey International Publishing.
Satellite temperatures
Measuring atmospheric temperature from satellite microwave measurements was invented by a team of scientists and engineers led by Roy Spencer and John Christy. It was first reported in detail in a now classic paper (Spencer & Christy, 1990):
The global satellite temperature data can be downloaded here.
Global average surface temperatures are too high.
It has long been known that modern global average surface temperature datasets show too much warming, although the reasons for the problem are often debated. We know the exaggerated rate of surface warming exists by comparing satellite estimates, ocean temperature estimates, and rural only temperatures to the standard land & ocean datasets. All independent rates of warming are less than the standard land & ocean rates.
Soon, W., Connolly, R., Connolly, M., Akasofu, S. I., Baliunas, S., Berglund, J., . . . al., e. (2023). The Detection and Attribution of Northern Hemisphere Land Surface Warming (1850–2018) in Terms of Human and Natural Factors: Challenges of Inadequate Data. Climate, 11(9). doi:10.3390/cli11090179
Christy, J. R., Herman, B., Sr., R. P., Klotzbach, P., McNider, R. T., Hnilo, J. J., . . . Douglass, D. (2010). What Do Observational Datasets Say about Modeled Tropospheric Temperature Trends since 1979? Remote Sensing, 9, 2148-2169. doi:10.3390/rs2092148
Rae, J. W., Zhang, Y. G., Liu, X., Foster, G. L., Stoll, H. M., & Whiteford, R. D. (2021). Atmospheric CO2 over the Past 66 Million Years from Marine Archive. Annual Review of Earth and Planetary Sciences, 49(1), 609-641. doi:10.1146/annurev-earth-082420-063026
Figure 6. Atmospheric CO2 concentration from proxies for the past 66 million years. Source (Rae, et al., 2021).
CO2 is plant food, more means more plants.
More CO2 fertilizes plants, and they grow faster in the presence of CO2, which is why CO2 is pumped into greenhouses. More CO2 also makes plants more drought resistant. More details here.
Chen, X., Chen, T., He, B., Liu, S., Zhou, S., & Shi, T. (2024). The global greening continues despite increased drought stress since 2000. Global Ecology and Conservation, 49. doi:10.1016/j.gecco.2023.e02791
CO2 dropped to 180 ppm 20,000 years ago and some plants died of CO2 starvation.
At CO2 partial pressures of 15 Pa or lower (roughly 150 ppm at sea level), most plants will either die or lose their ability to reproduce. In some areas in the last glacial maximum these conditions were possible.
Neftel, A., Moor, E., & Oeschger, H. (1985). Evidence from polar ice cores for the increase in atmospheric CO2 in the past two centuries. Nature, 315. doi:10.1038/315045a0
Soon, W. (2007). Implications of the Secondary Role of Carbon Dioxide and Methane Forcing in Climate Change: Past, Present, and Future. Physical Geography, 2, 97-125. doi:10.2747/0272-3646.28.2.97
Renee Hannon discusses problems with ice core CO2 estimates here.
CO2 has never driven temperature, it’s the opposite.
See figure 3 and the discussion around it.
Koutsoyiannis, D., Onof, C., Kundzewicz, Z. W., & Christofides, A. (2023). On Hens, Eggs, Temperatures and CO2: Causal Links in Earth’s Atmosphere. Sci, 5(3). doi:10.3390/sci5030035
Soon, W. (2007). Implications of the Secondary Role of Carbon Dioxide and Methane Forcing in Climate Change: Past, Present, and Future. Physical Geography, 2, 97-125. doi:10.2747/0272-3646.28.2.97
The 1930s were very warm.
The most pronounced warming in the historical global climate record, prior to the warming from 1980 to 2000, occurred in the first half of the 20th century. It peaked in the late 1930s.
Hegerl, G. C., Brönnimann, S., Schurer, A., & Cowan, T. (2018). The early 20th century warming: Anomalies, causes, and consequences. WIREs Climate Change, 9(4). doi:10.1002/wcc.522
Climate models do not capture this period of warming very well because they rely too much on CO2. In all likelihood, CO2 played a very small role in the early 20th century warming.
From 1945 to 1976 the world cooled
Guy Callendar published a major paper introducing his collection of past CO2 concentration measurements and global temperatures in 1938. The study tried to show that they correlated in the fashion predicted by Svante Arrhenius thirty years earlier and that CO2 controlled Earth’s temperature. Unfortunately, just after he published the paper the world began to cool as CO2 concentration increased rapidly during the post war industrial boom. The following plot of global temperatures is from HadCRUT4.
Figure 7. Plot of the HadCRUT4 global surface temperature average and the NOAA/NASA CO2 dataset in light gray. The CO2 concentration is shown as the logarithm to the base two so it can be compared directly to temperature. Notice the correlation is good after 1980, but poor before then.
In figure 7 we see that CO2 increases from about 1945 to 1980 while global average temperature falls.
Callendar, G. S. (1938). The artificial production of carbon dioxide and its influence on temperature. Q. J. R. Meteorol. Soc., 64, 223-240. doi:10.1002/qj.49706427503
Climate models overestimated observed temperature increases.
From the IPCC AR6 WGI report:
“Hence, we assess with medium confidence that CMIP5 and CMIP6 models continue to overestimate observed warming in the upper tropical troposphere over the 1979–2014 period by at least 0.1°C per decade, in part because of an overestimate of the tropical SST trend pattern over this period.“(AR6 WGI, page 444).
McKitrick, R., & Christy, J. (2018, July 6). A Test of the Tropical 200- to 300-hPa Warming Rate in Climate Models, Earth and Space Science. Earth and Space Science, 5(9), 529-536. doi:10.1029/2018EA000401
McKitrick, R., & Christy, J. (2020). Pervasive Warming Bias in CMIP6 Tropospheric Layers. Earth and Space Science, 7. doi:10.1029/2020EA001281
IPCC. (2021). Climate Change 2021: The Physical Science Basis. In V. Masson-Delmotte, P. Zhai, A. Pirani, S. L. Connors, C. Péan, S. Berger, . . . B. Zhou (Ed.)., WG1. Retrieved from https://www.ipcc.ch/report/ar6/wg1/
Climate models do not reproduce the ocean cycles properly.
From Eade, 2022:
“This suggests that current climate models do not fully represent important aspects of the mechanism for low frequency variability of the NAO.”Eade, et al. 2022
Eade, R., Stephenson, D., & Scaife, A. (2022). Quantifying the rarity of extreme multi‑decadal trends: how unusual was the late twentieth century trend in the North Atlantic Oscillation? Climate Dynamics, 58, 1555–1568 . doi:10.1007/s00382-021-05978-4
The NAO, the North Atlantic Oscillation, is an important ocean oscillation.
One of the best indicators of the weakness of the CMIP climate models is the fact that they do not reproduce or include as input, these vital climate indicators. For example, see the discussion on the “AMV” (AMV is what AR6 calls the AMO) in AR6 WGI page 504. The “AMV-like” signal in the climate models is too weak, following is a quote from AR6:
“On average, the duration of modelled AMV episodes is too short, the magnitude of AMV is too weak and its basin-wide SST spatial structure is limited by the poor representation of the link between the tropical North Atlantic and the subpolar North Atlantic/Nordic seas. Such mismatches between observed and simulated AMV have been associated with intrinsic model biases in both mean state and variability in the ocean and overlying atmosphere. For instance, compared to available observational data CMIP5 models underestimate the ratio of decadal to interannual variability of the main drivers of AMV, namely the AMOC, NAO and related North Atlantic jet variations … which has strong implications for the simulated temporal statistics of AMV, AMV-induced teleconnections and AMV predictability.”AR6, page 504
If they can’t model these important oscillations correctly, their models are wrong.
There is no relationship between CO2 concentration and climate.
Besides the lack of a correlation in figure 7, there is also no correlation between CO2 and climate over the entire Holocene as shown in Figure 4 here. This lack of correlation has been called the Holocene Temperature Conundrum.
Kaufman, D., & Broadman, E. (2023, February 15). Revisiting the Holocene global temperature conundrum. Nature, 614, 425-435. Retrieved from https://doi.org/10.1038/s41586-022-05536-w
Liu, Z., Zhu, J., Rosenthal, Y., Zhang, X., Otto-Bliesner, B. L., Timmermann, A., . . . Timm, O. E. (2014). The Holocene temperature conundrum. PNAS, 111. Retrieved from http://www.pnas.org/content/111/34/E3501.short
There is no evidence that the Earth is warmer today than in the past.
See figures 2 and 4 and the references.
There is no evidence that CO2 is now dangerously high.
The CO2 concentration has been many times higher than today in the past, and the only thing that happened was the Earth became greener.
Chen, X., Chen, T., He, B., Liu, S., Zhou, S., & Shi, T. (2024). The global greening continues despite increased drought stress since 2000. Global Ecology and Conservation, 49. doi:10.1016/j.gecco.2023.e02791
Also see this essay on the very warm PETM, 56 million years ago.
Clouds are important in climate change.
Clouds are the largest source of uncertainty in the IPCC calculation of the impact of CO2 concentration on climate according to AR6 WGI page 979. The net impact of changes in average cloud cover ranges from a positive feedback (warming) to a negative or cooling feedback, so even the direction of cloud-caused changes is unknown. Clouds cannot be modeled so their effect must be “parameterized,” which means they are varied in the model according to complex assumptions.
IPCC. (2021). Climate Change 2021: The Physical Science Basis. In V. Masson-Delmotte, P. Zhai, A. Pirani, S. L. Connors, C. Péan, S. Berger, . . . B. Zhou (Ed.)., WG1. Retrieved from https://www.ipcc.ch/report/ar6/wg1/
Ceppi, P., Brient, F., Zelinka, M., & Hartmann, D. (2017, July). Cloud feedback mechanisms and their representation in global climate models. WIRES Climate Change, 8(4). Retrieved from https://onlinelibrary.wiley.com/doi/full/10.1002/wcc.465
Galactic cosmic rays can contribute to creating clouds.
Galactic cosmic rays may help nucleate cloud formation.
Svensmark, H., Svensmark, J., Enghoff, M., & Shaviv, N. (2021). Atmospheric ionization and cloud radiative forcing. Sci Rep, 11. doi:10.1038/s41598-021-99033-1
Nir Shaviv’s spiral arm hypothesis
It is quite possible that Earth’s Ice Ages are related to the solar system’s path through the spiral arms of the Milky Way galaxy as proposed by Nir Shaviv.
Solar wind and its effect on galactic cosmic rays.
Dumbović, M., Vršnak, B., Čalogović, J., & Karlica, M. (2011). Cosmic ray modulation by solar wind disturbances. Astronomy and Astrophysics. doi:10.1051/0004-6361/201016006
Does solar activity correlate with climate changes?
Solar activity correlates with many features of Earth’s climate, including surface temperature, La Nina frequency, and polar vortex strength. For an overview see here.
Connolly et al., R. (2021). How much has the Sun influenced Northern Hemisphere temperature trends? Research in Astronomy and Astrophysics, 21(6). doi:10.1088/1674-4527/21/6/131
Soon, W., Connolly, R., & Connolly, M. (2015). Re-evaluating the role of solar variability on Northern Hemisphere temperature trends since the 19th century. Earth Science Reviews, 150, 409-452. Retrieved from https://www.sciencedirect.com/science/article/pii/S0012825215300349
Soon, W., Connolly, R., Connolly, M., Akasofu, S. I., Baliunas, S., Berglund, J., . . . al., e. (2023). The Detection and Attribution of Northern Hemisphere Land Surface Warming (1850–2018) in Terms of Human and Natural Factors: Challenges of Inadequate Data. Climate, 11(9). doi:10.3390/cli11090179
Connolly et al., R. (2023). Challenges in Detection and Attribution of Northern Hemisphere Surface Temperature Trends since 1850 Research in Astronomy and Astrophysics, 23(10). doi: 10.1088/1674-4527/acf18e
IPCC AR6 cannot attribute extreme weather to humans, but they try.
“… both thermodynamic and dynamic processes are involved in the changes of extremes in response to warming. Anthropogenic forcing (e.g., increases in greenhouse gas concentrations) directly affects thermodynamic variables, including overall increases in high temperatures and atmospheric evaporative demand, and regional changes in atmospheric moisture, which intensify heatwaves, droughts and heavy precipitation events when they occur (high confidence). Dynamic processes are often indirect responses to thermodynamic changes, are strongly affected by internal climate variability, and are also less well understood. As such, there is low confidence in how dynamic changes affect the location and magnitude of extreme events in a warming climate.”AR6 WGI, page 1527
While AR6 says that it is hard to explain changes in severe weather without anthropogenic forcing, it is “extremely difficult to detect and attribute changes” in precipitation/cyclones/drought/etc. to human activities (AR6 WGI, Chapter 11). They also note that “it remains uncertain whether past changes in Atlantic TC [tropical cyclone] activity are outside the range of natural variability.” AR6 WGI page 1588.
1930s in the U.S. were warmer than today.
This is a complicated issue and no definitive answer can be given either way. The surface temperature data quality and coverage in the U.S. varies a lot since 1930 and the data processing algorithms are often questioned. Further, the differences between the warmest years in the 1930s and today are small and well below the accuracy of the measurements.
James Hansen and a large group of co-authors concluded in 2001 that the U.S. mean temperature had just reached a level comparable to that of the 1930s. He concludes: “The U.S. was warm in 2000 but cooler than the warmest years in the 1930s…”
Hansen, J., Ruedy, R., Sato, M., Imhoff, M., Lawrence, W., Easterling, D., . . . Karl, T. (2001). A closer look at United States and global surface temperature change. Journal of Geophysical Research: Atmospheres, 106(D20), 23947-23963. doi:10.1029/2001JD000354
The U.S. surface temperature data (called USHCN or the U.S. Historical Climatology Network) are ambiguous, and the trend is highly dependent upon the corrections applied to it. Figure 8 compares the final processed CONUS (Contiguous U.S. states) temperature anomaly in blue to the raw temperature anomaly in orange. The important point to notice is that the raw data from the 1930s is nearly as high as raw modern temperatures because the “corrected” data in the 1930s is corrected down and the modern temperatures are “corrected” up. The reasons given for this pattern are controversial. The other unusual thing about the plot is the corrections to the modern data, which is presumably more accurate, are larger than the corrections in the 1930s.
The final temperatures, shown in figure 8 in blue, are highly processed and missing stations are filled in with data from nearby stations. The raw data shown in figure 8 are only the data from real stations, so how many functioning stations exist in any given year matters. Figure 9 shows the number of stations reporting each year in orange. The final station count is forced to be constant by the infilling algorithm.
Figure 8. Comparison of the continental U.S. (“CONUS”) USHCN v 2.5.5 weather station
The actual number of reporting weather stations in the 1930s and the 1990s is fairly high and only a few stations had to be infilled with the processing algorithm. Yet while the peak years in the 1930s and in the 1990s have similar raw data temperature anomalies, the final temperatures are different. This is the context behind the statement.
Figure 9. The number of weather stations reporting in each year is shown in orange. Only stations reporting in each of the 12 months of the year are counted to avoid seasonal anomalies. The number of values in the final dataset (some are infilled with the algorithm) are shown in blue. The apparent loss of “accuracy” in figure 8, after 2000 is at least partially due to the loss of reporting weather stations.
More on the U.S. temperature record, including additional references and datasets that indicate the 1930s is warmer than 2000, can be seen here. The post also provides the official explanation for the “corrections.”
James Hansen and co-authors also wrote the following in 1999, link:
“What’s happening to our climate? Was the heat wave and drought in the Eastern United States in 1999 a sign of global warming?
Empirical evidence does not lend much support to the notion that climate is headed precipitately toward more extreme heat and drought. The drought of 1999 covered a smaller area than the 1988 drought, when the Mississippi almost dried up. And 1988 was a temporary inconvenience as compared with repeated droughts during the 1930s “Dust Bowl” that caused an exodus from the prairies, as chronicled in Steinbeck’s Grapes of Wrath.” (James Hansen, 1999)
Winter temperatures are rising and summer temperatures have hardly changed.
This is a common assumption, but the real story of winter versus summer warming rates is more complex. Models predict that winters and nights will warm faster than summers and days, but this trend only happens in some regions of the Earth. In other areas it is opposite and no one really understands why (Balling, Michaels, & Knappenberger, 1998).
Balling, R., Michaels, P., & Knappenberger, P. (1998). Analysis of winter and summer warming rates in gridded temperature time series. Climate Research, 9. doi:10.3354/cr009175
Wildfires were worse in the 1930s.
Figure 10. U.S. forest area burned since 1926, from the National Interagency Fire Center.
No change in U.S. hurricanes.
There is no trend or a slight decline in continental U.S. landfalling hurricanes over the past 120 years.
Klotzbach, P. J., Bowen, S. G., Pielke, R., & Bell, M. (2018). Continental U.S. Hurricane Landfall Frequency and Associated Damage: Observations and Future Risks. Bull. Amer. Meteor. Soc, 99, 1359-1376. doi:10.1175/BAMS-D-17-0184.1
No change in global cyclones
Figure 11. Global major hurricane frequency, from Ryan Maue.
Figure 12. Global tropical cyclone frequency, from Ryan Maue.
Schneider, D. P. (2006). Antarctic temperatures over the past two centuries from ice cores. Geophysical Research Letters, 33(16). doi:10.1029/2006GL027057
“Beyond the Antarctic Peninsula there has been little significant change in temperature.”Turner, et al., 2019
Turner, J., Marshall, G. J., Clem, K., Colwell, S., Phillips, T., & Lu, H. (2019). Antarctic temperature variability and change from station data. International Journal of Climatology, 2986-3007. doi:10.1002/joc.6378
Figure 13. Antarctic temperatures.
Global drought has not changed.
Meteorological drought has not increased in at least the past 120 years.
Vicente-Serrano, S. M., Peña-Angulo, D., Beguería, S., Domínguez-Castro, F., Tomás-Burguera, M., Noguera, I., . . . Ahmed, E. K. (2022). Global drought trends and future projections. Phil. Trans. R. Soc. A, 380. doi:10.1098/rsta.2021.0285
Polar bear population is growing.
As of 2021 the world polar bear population was growing according to polar bear expert Susan Crockford.
Crockford, S. (2022). The State of the Polar Bear 2021. Global Warmig Policy Foundation.
Great barrier reef is growing and reached record levels.
Figure 14. Great Barrier Reef growth record, After Peter Ridd using data from the Australian Institute of Marine Science.
Climate change can kill maple trees?
This is highly speculative, but claimed, see here.
Climate change and prostitution.
Farley, M. (2022). Making the connections: resource extraction, prostitution, poverty, climate change, and human rights. The International Journal of Human Rights, 26(6), 1032-1055. doi:10.1080/13642987.2021.1997999
Climate change affects beer quality.
Mozny, M., Trnka, M., & Vlach, V. (2023). Climate-induced decline in the quality and quantity of European hops calls for immediate adaptation measures. Nature. doi:10.1038/s41467-023-41474-5
Climate change in video games.
Yes, there are climate change video games, see here and here.
If you don’t find climate change is a problem your money dries up.
“On March 7, 2019, Senator Schumer (together with Senators Carper, Reed, Van Hollen, White-house, Markey, Schatz, Smith, Blumenthal, Shaheen, Booker, Stabenow, Klobuchar, Hassan, Merkley, and Feinstein) introduced Senate bill S.729:”
“ . . . to prohibit the use of funds to Federal agencies to establish a panel, task force, advisory committee, or other effort to challenge the scientific consensus on climate change, and for other purposes.”Koonin, 2021, p 202
Incredibly shocking, the U.S. Senate attempting to legislate scientific research outcomes, it doesn’t get worse than this. Fortunately, the bill failed to pass, but the political pressure to find human’s caused recent climate changes is overwhelming.
Filing reports on how climate change affects businesses.
The U.S. SEC have tried to implement a new climate change impact filing requirement, see here. However the rule has been temporarily halted by the courts (see here).
It has been criticized as unnecessarily punitive and expensive.
Renewable energy is a trillion-dollar business.
A recent McKinsey report expects $9.2 trillion to be spent on reaching net zero by 2050.
Scafetta, N., & Willson, R. (2014). ACRIM total solar irradiance satellite composite validation versus TSI proxy models. Astrophysics and Space Science, 350(2), 421-442. Retrieved from https://link.springer.com/article/10.1007/s10509-013-1775-9
Soon, W., Connolly, R., & Connolly, M. (2015). Re-evaluating the role of solar variability on Northern Hemisphere temperature trends since the 19th century. Earth Science Reviews, 150, 409-452. Retrieved from https://www.sciencedirect.com/science/article/pii/S0012825215300349
Connolly et al., R. (2023). Challenges in Detection and Attribution of Northern Hemisphere Surface Temperature Trends since 1850 Research in Astronomy and Astrophysics, 23(10). doi: 10.1088/1674-4527/acf18e
We are looking for the range of natural variability.
“… a significant part of the 20th century warming may be interpreted as the result of natural climatic variations…”Humlum, 2011
Humlum, O., Solheim, J.-E., & Stordahl, K. (2011). Identifying natural contributions to late Holocene climate change. Global and Planetary Change, 79(1), 145-156. doi:10.1016/j.gloplacha.2011.09.005
Here is a discussion of natural variability in the Arctic by Judith Curry.
“These results support the notion that the enhanced wintertime warming over high northern latitudes from 1965 to 2000 was mainly a reflection of unforced variability of the coupled climate system.”(Wallace, Qiang, Smoliak, & Johanson, 2012)
Wallace, J., Q. F., Smoliak, B. V., & Johanson, C. M. (2012). Simulated versus observed patterns of warming over the extratropical Northern Hemisphere continents during the cold season. Earth, Atmospheric, And Planetary Sciences, 109(36). doi:10.1073/pnas.1204875109
More government control.
“The politician’s power increases because exercising power increases it and people will give up their freedoms in exchange for security, whether the danger is real or not.”(May, Politics and Climate Change: A History, 2020c, p. 15)
May, A. (2020c). Politics and Climate Change: A History. Springfield, Missouri: American Freedom Publications.
“No matter if the science of global warming is all phony…climate change [provides] the greatest opportunity to bring about justice and equality in the world.”Christine Stewart, Canadian Minister of the Environment, speaking to the editors and reporters of the Calgary Herald in 1998.
“This is the first time in the history of mankind that we are setting ourselves the task of intentionally, within a defined period of time to change the economic development model that has been reigning for at least 150 years, since the Industrial Revolution.”Christiana Figueres, February 4th, 2015
None of the countries participating in the 1997 Kyoto Protocol had any idea what the treaty would cost them, either in jobs or standard of living. They also had no idea what the benefits would be. William Nordhaus, the famous Yale economist and Nobel laureate, called the Kyoto Protocol a:
“conceptual disaster; it has no coherence politically or economically or environmentally.”William Nordhaus, (Yale University, 2007, pp. 131-132).
Kyoto had little to do with climate change, it was mainly an enormous transfer of money from wealthy countries to poor countries. (May, Politics and Climate Change: A History, 2020c, pp. 236-237)
Burning wood and dung for heat or to cook is deadly.
“Traditional biofuels” are the burning of wood and dung in houses or businesses for heat, light, or cooking. This is not desirable because it produces toxic air pollution. The indoor air pollution caused by traditional biofuels, causes 4% of global deaths. A major study, published in The Lancet, estimates that more than two million deaths can be attributed to indoor air pollution in 2019 (Christopher Murray, 2020). The World Health Organization (WHO) estimates that four million deaths, every year, are caused by indoor air pollution. Domestic wood burning is not just a problem in the developing world, the European Environment Agency, WHO, and the Netherlands Organization for Applied Scientific Research suggest that over 40% of toxic emissions are from residential biomass burning. The UK Department for Environment, Food, and Rural affairs (DEFRA) estimates that 38% of UK air pollution is due to wood-burning stove emissions.”
“The energy-intensiveness of industrial agriculture is well-documented”
“The energy basis of industrial food production has a rich tradition, but quantitative analysis of changes in energy use in agriculture has been limited by the lack of consistent data. This analysis used a new methodology for calculating the direct and indirect use of fossil fuels in agriculture. The procedure was used to quantify energy use in USA agriculture from 1910 to 1990. The results showed a substantial overall increase in energy use from 1910 through the 1970s, and a shift from gasoline to diesel fuel and electricity. The use of all fuels declined in the 1980s.”
“Energy productivity rose in the 1980s due to a diminution in the rate of energy use, a reduction in the number of harvested acres, and larger farms. The results showed a clear response of farmers to higher energy prices that resulted in technical and managerial changes that improved energy productivity.”(Cleveland, 1995)
In essence the higher energy prices in the 1980s led to small farmers selling out to larger more efficient farmers, improving overall productivity. Small farmers being forced to sell out to larger farmers was epidemic in the 1980s and mostly due to the high cost of gasoline and diesel.
Cleveland, C. (1995, September). The direct and indirect use of fossil fuels and electricity in USA agriculture, 1910-1990. Agriculture, Ecosystems and Environment, 111-121. doi:10.1016/0167-8809(95)00615-Y
Fossil fuels built western civilization.
The 20th century has been called the “Age of Oil” and with good reason. It was a century when life expectancy doubled and extreme poverty dropped from 80% to less than 10%. The drop in poverty is closely correlated (R2= 0.99) to fossil fuels consumed.
Yergin, D. (1991). The Prize. New York: Touchstone.
“In recent years, the overused word ‘sustainability’ has fostered a narrative in which human needs and aspirations have taken a back seat to the green austerity of Net Zero and ‘degrowth’. The ruling classes of a fading West are determined to save the planet by immiserating their fellow citizens. Their agenda is expected to cost the world $6 trillion per year for the next 30 years. Meanwhile, they will get to harvest massive green subsidies and live like Renaissance potentates.”See Joel Kotkin, Spiked, here for more.
China builds two coal powerplants a week.
In 2022 China granted permits for 106 coal power plants across 82 sites.
China uses more coal than the rest of the world combined.
Figure 15. Coal consumption for the whole world compared to China from ourworldindata.org.
Anti-environmentalism is rampant.
Polish farmers protest EU environmental regulations.
Belgian farmers protest excessive environmental rules.
USA Today published a supposed fact check claiming solar activity is not responsible for climate change. This is misleading at best, and foolishly wrong at worst. Various types of changes in solar activity have long been associated with changes in the Earth’s temperature and climate, on short, mid-term, and longer time scales.
USA Today published a supposed fact check claiming solar activity is not responsible for climate change. This is misleading at best, and foolishly wrong at worst. Various types of changes in solar activity have long been associated with changes in the Earth’s temperature and climate, on short, mid-term, and longer time scales.
The USA Today article by Kate S. Petersen, “The sun is mighty, but modern climate change is caused by human activity | Fact check,” presents itself as a fact check on a popular Facebook post. Wow! Responding to somebody’s certainly Facebook post is taking on hard hitting news from a reliable source! Still, when one examines the post, and compares it to the supposed fact check, the Facebook post is closer to the truth than Petersen’s and USA Today’s story.
“The implied claim is wrong,” Petersen writes. “While the sun significantly impacts Earth’s climate, it is not responsible for modern climate change.
“While the amount of solar energy striking the Earth fluctuates on an 11-year cycle, there hasn’t been a net increase since the 1950s, according to NASA,” Petersen continues. “However, global surface temperatures have risen dramatically.”
Petersen either is unaware of or simply ignored the fact that the 11-year solar cycles during which Sol’s magnetic fields flip are just one type of solar cycle that can drive temperature and climate changes on the earth. Sunspots and solar flares happen seemingly randomly though with some consistency, and 1,000 and 1,500 year cycles, and Milankovitch cycles also occur. All of these activities and others impact the Earth’s temperatures. As discussed at Climate at a Glance: The Sun’s Impact on Climate Change, historically through the present day, solar activity correlates quite well with climate change, better than changes in CO2. (see figures 1-3, below)
Figure 1. Changes in the Sun’s energy output since 1900. The Sun’s energy output has increased since the 1600’s with its most recent increase occurring during the 20th century. Source: J. Lean, Geophysical Research Letters, Vol 27, No. 16 (2000).
Figure 2: Temperature history according to the United Nations IPCC First Assessment Report. The top graph shows temperatures during the past 1 million years. The middle graph shows temperatures during the past 12,000 years. The bottom graph shows temperatures during the past 1,000 years. Present temperatures are at the far right. Source: IPCC First Assessment Report, United Nations, p. 202.
Figure 3. Temperature changes vs. changes in the Sun’s energy output and changes in atmospheric carbon dioxide concentrations. The graph on the left shows 20th century temperature changes in blue vs. changes in the Sun’s energy output in red. The graph on the right shows 20th century changes in blue vs. changes in atmospheric carbon dioxide emissions in red. W. Soon, et al., “Solar irradiance modulation of Equator-to-Pole (Arctic) temperature gradients: Empirical evidence for climate variation on multi-decadal timescales,” Journal of Atmospheric and Solar-Terrestrial Physics, 93, 45-56.
All the myriad ways solar activity impacts the Earth are not fully understood. Changes in solar output and their impact on solar winds are plausible explanations for temperature shifts on some time scales. Scientific research also suggests another type of forcing from the sun, its impact on volume of cosmic rays entering the earth’s atmosphere, which also impacts cloud formation and rainfall.
The point is, when Petersen and the government agencies she references state that the sun can’t be a factor in current climate change, they are only looking at one type of solar activity on a single time scale. Our solar system isn’t that simple.
To buttress her claim that the sun isn’t causing or significantly contributing to present climate change Petersen quotes Josh Willis, a NASA climate scientist, who told USA Today that “the amount of warming we see matches what we expect based on the increased CO2 we’ve added. The timing of the warming matches the timing of the CO2 increase caused by people.”
Willis’s claim doesn’t match the facts. The Earth began to warm in the mid- to late 19th century, before humans began emitting large significant amounts of CO2 into the atmosphere, then after the 1940s, even as global industrialization and anthropogenic CO2 emissions were increasing at a rapid pace, the earth began cooling, leading some scientists and media outlets by the 1970s to warn that an ice age might be coming. Then, the Earth started warming in the 1980s, only to plateau or pause for 15 years beginning in the late 1990s, despite CO2’s steady increase. There has, in fact, been no good correlation between CO2 concentrations and temperature changes throughout the latter 20th and early 21st centuries.
Also, as we’ve discussed dozens of times at Climate Realism, CO2 driven temperature changes projected by climate models don’t, in fact, accurately reflect recent warming trends. Ground-level temperature measurements, weather balloon temperature measurements, and satellite temperature measurements are far lower than model projections built on the assumption that CO2 is the prime forcing factor for global warming. As a result, Willis is simply wrong when he says, “the amount of warming we see matches what we expect based on the increased CO2 we’ve added.”
The physics and factors that drive the Earth’s climate conditions are many, varied, and complex. The Earth is not the simple linear system described in climate models and presented by Petersen and USA Today. Carbon dioxide is likely one factor influencing the recent modest warming, but the sun and numerous other factors are almost certainly having an impact as well—arguably playing role greater than the increase in greenhouse gases.
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