Climate Heresy: To Avoid Extinction We Need More, Not Less CO2

A recent preprint advances the heretical idea that all life on Earth will perish in as little as 42,000 years unless we take action to boost – not lower – the CO₂ level in the atmosphere. The preprint’s author claims that is when the level could fall to a critical 150 ppm (parts per million), below which plants die due to CO₂ starvation.

Some of the arguments of author Brendan Godwin, a former Australian meteorologist, are sound. But Godwin seriously underestimates the time frame for possible extinction. It can easily be shown that the interval is in fact millions of years.

Plants are essential for life because they are the source, either directly or indirectly, of all the food that living creatures eat. Both CO₂ and water, as well as sunlight, are necessary for the photosynthesis process by which plants grow. In the carbon cycle, the ultimate repository for CO₂ pulled out of both the air and the oceans is limestone or calcium carbonate (CaCO₃), of which there are two types: chemical and biological.

Chemical limestone is formed from the weathering over time of silicate rocks, which make up about 90% of the earth’s crust, and to a lesser extent, of carbonate rocks. Silicate weathering draws CO₂ out of the atmosphere when the CO₂ combines with rainwater to form carbonic acid (H₂CO₃) that dissolves silicates. A representative chemical reaction for calcium silicate (CaSiO₃) is

CaSiO₃ + 2CO₂ + H₂O → Ca²⁺ + 2HCO₃^- + SiO₂.

The resulting calcium (Ca²⁺) and bicarbonate (HCO₃^-) ions, together with dissolved silica (SiO₂), are then carried away mostly by rivers to the oceans. There, calcium carbonate (CaCO₃) precipitates when marine organisms utilize the Ca²⁺ and HCO₃^- ions to build their skeletons and shells:

Ca²⁺ + 2HCO₃^- → CaCO₃ + CO₂ + H₂O.

Once the organisms die, the CaCO₃ skeletons and shells sink to the ocean floor and are deposited as chemical limestone in deep-sea sediment.

Biological limestone, on the other hand, comes from fossilized coral reefs and is approximately twice as abundant as chemical limestone. Just like the marine organisms or plankton that ultimately form chemical limestone, the polyps that constitute a coral build the chambers in which they live out of CaCO₃. Biological limestone from accumulated coralline debris accumulates mainly in shallow ocean waters, and is transformed over time by plate tectonic processes into major outcrops on land and in the highest mountains – even the top of Mount Everest.

Godwin’s estimate of only 42,000 years before life is extinct stems from a misunderstanding about the carbon cycle, which is illustrated in the figure below depicting the global carbon budget in gigatonnes of carbon. Carbon stocks are shown in blue, with annual flows between carbon reservoirs shown in red.

The carbon sequestered as chemical limestone in deep-sea sediment, and as biological limestone, is represented by the 100 million gigatonnes stored in the earth’s crust. As you can see, today’s atmosphere contains approximately 850 gigatonnes of carbon (as CO₂) and the oceans another 38,000 gigatonnes, most of which was originally dissolved as atmospheric CO₂.

The erroneous estimate of Godwin simply divides the 38,000 gigatonnes of carbon in the oceans by 0.9 gigatonnes per year, which is the known rate of carbon sequestration into chemical and biological limestone combined; chemical weathering of silicate rocks contributes 0.3 gigatonnes per year, while fossilized coral contributes 0.6 gigatonnes per year.

This calculation is wrong because Godwin fails to understand that the carbon cycle is dynamic, with carbon constantly being exchanged between land, atmospheric and ocean reservoirs. The carbon sequestered into chemical and biological limestone is included in the flow from rivers to ocean and in ocean uptake in the figure above. But there are many flows in the opposite direction that replenish carbon in the atmosphere, even when fossil fuel burning is ignored. Simply depleting the ocean reservoir will not lead to extinction.

A realistic estimate can be made by assuming that atmospheric carbon will continue to decline at the same rate as it has over the past 540 million years. As shown in the next figure, the concentration of CO₂ in the atmosphere over that period has dropped from a high of about 7,000 ppm at the beginning of the so-called Cambrian Explosion, to today’s 417 ppm.

Using a conversion factor of 2.13 gigatonnes of carbon per ppm of atmospheric CO₂, the drop corresponds to an average decline of approximately 26 kilotonnes of carbon per year. At that rate, the 150 ppm (320 gigatonnes) level at which life on earth would begin to die will not be reached until 22 million years from now.

Given that the present CO₂ level is rising due to fossil fuel emissions, the 22 million years is likely to be an underestimate. However, ecologist Patrick Moore points out that a future cessation of fossil fuel burning could make the next ice age – which may be only thousands of years away – devastating for humanity, as temperatures and CO₂ levels could fall to unprecedentedly low levels, drastically reducing plant growth and creating widespread famine.

Next: New Research Finds Climate Models Unable to Reproduce Ocean Surface Temperatures

The Scientific Method at Work: The Carbon Cycle Revisited, Again

In a previous post, I demonstrated how a new model of the carbon cycle, described in a 2020 preprint, is falsified by empirical observations that fail to confirm a prediction of the model. The crucial test of any scientific hypothesis is whether its predictions match real-world observations. But a newly publicized discussion now questions the foundations of the model itself.

The model in question, developed by U.S. physicist Ed Berry, describes quantitatively the exchange of carbon between the earth’s land masses, atmosphere and oceans. Berry argues that natural emissions of CO₂ into the atmosphere since 1750 have increased as the world has warmed, and that only 25% of the increase in atmospheric CO₂ after 1750 is from humans.

This is contrary to the CO₂ global warming hypothesis that human emissions have caused all of the CO₂ increase above its preindustrial level in 1750 of 280 ppm (parts per million). The CO₂ hypothesis is based on the apparent correlation between rising worldwide temperatures and the CO₂ level in the lower atmosphere, which has gone up by 49% over the same period.

Natural CO₂ emissions are part of the carbon cycle that includes fauna and flora, as well as soil and sedimentary rocks. Human CO₂ from burning fossil fuels constitutes less than 5% of total CO₂ emissions into the atmosphere, the remaining emissions being natural. Atmospheric CO₂ is absorbed by vegetation during photosynthesis, and by the oceans through precipitation. The oceans also release CO₂ as the temperature climbs.

In a recent discussion between Ed Berry and the CO₂ Coalition, the Coalition says that Berry confuses the 5% of CO₂ emissions originating from fossil fuels with the percentage of atmospheric CO₂ molecules that actually come from fossil fuel burning. This percentage is very small, because the molecules are continually recycled and thus “diluted” with the much larger quantity of CO₂ molecules from natural emissions.

Physicist David Andrews amplifies this comment of the CO₂ Coalition in a 2022 preprint, by pointing out that total CO₂ emissions into the atmosphere from human activity over time exceed the rise in atmospheric CO₂ over the same interval. So all the modern CO₂ increase (from 280 to 416 ppm) must come from human emissions. Adds Andrews:

… we know immediately that land and sea reservoirs together have been net sinks, not sources, of carbon during this period. We can be sure of this without knowledge of the detailed inventory changes of individual non-atmospheric reservoirs. … Global uptake is simply what is left over after atmospheric accumulation has been subtracted from total emissions. If more carbon was injected into the atmosphere by fossil fuel burning than stayed there, it had to have gone somewhere else.

The arguments of both Andrews and the CO₂ Coalition are at odds with Berry’s calculations, depicted in the figure below; H denotes human and N natural CO₂.

This figure shows that the sum total of human CO₂ emissions (blue dots) exceeds the rise in atmospheric CO₂ (black dots), at least since 1960, in agreement with Andrews’ comment. Where Berry goes astray is by claiming that natural emissions, represented by the area between the blue and red solid lines, have not stayed at the same 280 ppm level over time, but have gone up as global temperatures have increased.

Such a claim is extremely puzzling, as the model requires the addition to the atmosphere of approximately 100 ppm of CO₂ from natural sources since 1840 – an amount far in excess of the roughly 10 ppm of CO₂ outgassed from the oceans as ocean temperatures rose about 1 degree Celsius (1.8 degrees Fahrenheit) over that time. Berry acknowledges the problem, but only proposes unphysical explanations, such as mysteriously adding new carbon to the carbon cycle.

The falsified prediction of his model, on the other hand, involves the atmospheric concentration of the radioactive carbon isotope ¹⁴C, produced by cosmic rays interacting with nitrogen in the upper atmosphere. The concentration of ¹⁴C almost doubled following above-ground nuclear bomb tests in the 1950s and 1960s, and has since been slowly dropping. At the same time, concentrations of the stable carbon isotopes ¹²C and ¹³C, generated by fossil-fuel burning, have been steadily rising. Because the carbon in fossil fuels is millions of years old, all the ¹⁴C in fossil-fuel CO₂ has decayed away.

Although Berry claims that his model’s prediction of the recovery in ¹⁴C concentration since 1970 matches experimental observations, Andrews found that Berry had confused the concentration of ¹⁴C with its isotopic or abundance ratio relative to ¹²C, as I described in my earlier post.

As a result, Berry’s carbon cycle model does not replicate the actual measurements of ¹⁴C concentration in the atmosphere since 1970, as he insists it does. Needless to say, he also disputes the arguments of Andrews and the CO₂ Coalition about the very basis of his model.

Next: Challenges to the CO2 Global Warming Hypothesis: (7) Ocean Currents More Important than the Greenhouse Effect

The Scientific Method at Work: The Carbon Cycle Revisited

The crucial test of any scientific hypothesis is whether its predictions match real-world observations. If empirical evidence doesn’t confirm the predictions, the hypothesis is falsified. The scientific method then demands that the hypothesis be either tossed out, or modified to fit the evidence. This post illustrates just such an example of the scientific method at work.

The hypothesis in question is a model of the carbon cycle, which describes quantitatively the exchange of carbon between the earth’s land masses, atmosphere and oceans, proposed by physicist Ed Berry and described in a previous post. Berry argues that natural emissions of CO₂ since 1750 have increased as the world has warmed, contrary to the CO₂ global warming hypothesis, and that only 25% of the increase in atmospheric CO₂ after 1750 is due to humans.

One prediction of his model, not described in my earlier post, involves the atmospheric concentration of the radioactive carbon isotope ¹⁴C, produced by cosmic rays interacting with nitrogen in the upper atmosphere. It’s the isotope commonly used for radiocarbon dating. With a half-life of 5,730 years, ¹⁴C is absorbed by living but not dead biological matter, so the amount of ¹⁴C remaining in a dead animal or plant is a measure of the time elapsed since its death. Older fossils contain less ¹⁴C than more recent ones.

Berry’s prediction is of the recovery since 1970 of the ¹⁴C level in atmospheric CO₂, a level that became elevated by radioactive fallout from above-ground nuclear bomb testing in the 1950s and 1960s. The atmospheric concentration of ¹⁴C almost doubled following the tests and has since been slowly dropping – at the same time as concentrations of the stable carbon isotopes ¹²C and ¹³C, generated by fossil-fuel burning, have been steadily rising. Because the carbon in fossil fuels is millions of years old, all the ¹⁴C in fossil-fuel CO₂ has decayed away.

The recovery in ¹⁴C concentration predicted by Berry’s model is illustrated in the figure below, where the solid line purportedly shows the empirical data and the black dots indicate the model’s predicted values from 1970 onward. It appears that the model closely replicates the experimental observations which, if true, would verify the model.

However, as elucidated recently by physicist David Andrews, the prediction is flawed because the data depicted by the solid line in the figure are not the concentration of ¹⁴C, but rather its isotopic or abundance ratio relative to ¹²C. This ratio is most often expressed as the “delta value” Δ¹⁴C, calculated from the isotopic ratio R = ¹⁴C/¹²C as

Δ¹⁴C = 1000 x (R_sample/R_standard – 1), measured in parts per thousand.

The relationship between Δ¹⁴C and the ¹⁴C concentration is

¹⁴C conc = (total carbon conc) x R_standard x (Δ¹⁴C/1000 + 1).

Unfortunately, Berry has failed to distinguish between Δ¹⁴C and ¹⁴C concentration. As Andrews remarks, “as Δ¹⁴C [calculated from measured isotope ratios] approaches zero in 2020, this does not mean that ¹⁴C concentrations have nearly returned to 1955 values. It means that the isotope abundance ratio has nearly returned to its previous value. Therefore, since atmospheric ¹²CO₂ has increased by about 30% since 1955, the ¹⁴C concentration remains well above its pre-bomb test value.”

This can be seen clearly in the next figure, showing Andrews’ calculations of the atmospheric ¹⁴CO₂ concentration compared to the experimentally measured concentration of all CO₂ isotopes, in parts per million by volume (ppmv), over the last century. The behavior of the ¹⁴CO₂ concentration after 1970 is unquestionably different from that of Δ¹⁴C in the previous figure, the current concentration leveling off at close to 350 ppmv, about 40% higher than its 1955 pre-bomb spike value, rather than reverting to that value. In fact, the ¹⁴CO₂ concentration is currently increasing.

At first, it seems that the ¹⁴CO₂ concentration in the atmosphere should decrease with time as fossil-fuel CO₂ is added, since fossil fuels are devoid of ¹⁴C. The counterintuitive increase arises from the exchange of CO₂ between the atmosphere and oceans. Normally, there’s a balance between ¹⁴CO₂ absorbed from the atmosphere by cooler ocean water at the poles and ¹⁴CO₂ released into the atmosphere by warmer water at the equator. But the emission of ¹⁴C-deficient fossil-fuel CO₂ into the atmosphere perturbs this balance, with less ¹⁴CO₂ now being absorbed by the oceans than released. The net result is a buildup of ¹⁴CO₂ in the atmosphere.

As the figures above show, the actual ¹⁴C concentration data falsify Berry’s model, as well as other similar ones (see here and here). The models, therefore, must be modified in order to accurately describe the carbon cycle, if not discarded altogether.

The importance of hypothesis testing was aptly summed up by Nobel Prize winning physicist Richard Feynman (1918-88), who said in a lecture on the scientific method:

If it [the hypothesis] disagrees with experiment, it’s WRONG.  In that simple statement is the key to science.  It doesn’t make any difference how beautiful your guess is, it doesn’t matter how smart you are, who made the guess, or what his name is … If it disagrees with experiment, it’s wrong.  That’s all there is to it.

Next: How Clouds Hold the Key to Global Warming

Challenges to the CO2 Global Warming Hypothesis: (1) A New Take on the Carbon Cycle

Central to the dubious belief that humans make a substantial contribution to climate change is the CO₂ global warming hypothesis. The hypothesis is that observed global warming – currently about 1 degree Celsius (1.8 degrees Fahrenheit) since the preindustrial era – has been caused primarily by human emissions of CO₂ and other greenhouse gases into the atmosphere. The CO₂ hypothesis is based on the apparent correlation between rising worldwide temperatures and the CO₂ level in the lower atmosphere, which has gone up by approximately 47% over the same period.

In this series of blog posts, I’ll review several recent research papers that challenge the hypothesis. The first is a 2020 preprint by U.S. physicist and research meteorologist Ed Berry, who has a PhD in atmospheric physics. Berry disputes the claim of the IPCC (Intergovernmental Panel on Climate Change) that human emissions have caused all of the CO₂ increase above its preindustrial level in 1750 of 280 ppm (parts per million), which is one way of expressing the hypothesis.

The IPCC’s CO₂ model maintains that natural emissions of CO₂ since 1750 have remained constant, keeping the level of natural CO₂ in the atmosphere at 280 ppm, even as the world has warmed. But Berry’s alternative model concludes that only 25% of the current increase in atmospheric CO₂ is due to humans and that the other 75% comes from natural sources. Both Berry and the IPCC agree that the preindustrial CO₂ level of 280 ppm had natural origins. If Berry is correct, however, the CO₂ global warming hypothesis must be discarded and another explanation found for global warming.

Natural CO₂ emissions are part of the carbon cycle that accounts for the exchange of carbon between the earth’s land masses, atmosphere and oceans; it includes fauna and flora, as well as soil and sedimentary rocks. Human CO₂ from burning fossil fuels constitutes less than 5% of total CO₂ emissions into the atmosphere, the remaining emissions being natural. Atmospheric CO₂ is absorbed by vegetation during photosynthesis, and by the oceans through precipitation. The oceans also release CO₂ as the temperature climbs.

Berry argues that the IPCC treats human and natural carbon differently, instead of deriving the human carbon cycle from the natural carbon cycle. This, he says, is unphysical and violates the Equivalence Principle of physics. Mother Nature can't tell the difference between fossil fuel CO₂ and natural CO₂. Berry uses physics to create a carbon cycle model that simulates the IPCC’s natural carbon cycle, and then utilizes his model to calculate what the IPCC human carbon cycle should be.

Berry’s physics model computes the flow or exchange of carbon between land, atmosphere, surface ocean and deep ocean reservoirs, based on the hypothesis that outflow of carbon from a particular reservoir is equal to its level or mass in that reservoir divided by its residence time. The following figure shows the distribution of human carbon among the four reservoirs in 2005, when the atmospheric CO₂ level was 393 ppm, as calculated by the IPCC (left panel) and Berry (right panel).

A striking difference can be seen between the two models. The IPCC claims that approximately 61% of all carbon from human emissions remained in the atmosphere in 2005, and no human carbon had flowed to land or surface ocean. In contrast, Berry’s alternative model reveals appreciable amounts of human carbon in all reservoirs that year, but only 16% left in the atmosphere. The IPCC’s numbers result from assuming in its human carbon cycle that human emissions caused all the CO₂ increase above its 1750 level.

The problem is that the sum total of all human CO₂ emitted since 1750 is more than enough to raise the atmospheric level from 280 ppm to its present 411 ppm, if the CO₂ residence time in the atmosphere is as long as the IPCC claims – hundreds of years, much longer than Berry’s 5 to 10 years. The IPCC’s unphysical solution to this dilemma, Berry points out, is to have the excess human carbon absorbed by the deep ocean alone without any carbon remaining at the ocean surface.

Contrary to the IPCC’s claim, Berry says that human emissions don’t continually add CO₂ to the atmosphere, but rather generate a flow of CO₂ through the atmosphere. In his model, the human component of the current 131 (= 411-280) ppm of added atmospheric CO₂ is only 33 ppm, and the other 98 ppm is natural.

The next figure illustrates Berry’s calculations, showing the atmospheric CO₂ level above 280 ppm for the period from 1840 to 2020, including both human and natural contributions. It’s clear that natural emissions, represented by the area between the blue and red solid lines, have not stayed at the same 280 ppm level over time, but have risen as global temperatures have increased. Furthermore, the figure also demonstrates that nature has always dominated the human contribution and that the increase in atmospheric CO₂ is more natural than human.

Other researchers (see, for example, here and here) have come to much the same conclusions as Berry, using different arguments.

Next: Challenges to the CO2 Global Warming Hypothesis: (2) Questioning Nature’s Greenhouse Effect