Scientists Acquit Fossil Fuels of Global Warming

by | Mar 28, 2024 | Climate

Climate activists, government officials, and the United Nations claim that fossil fuel emissions caused global warming. Now scientists have disproved that claim.

This brief reports new facts about the impact of fossil fuels on global warming. The new scientific revelations, and the consequences of ignoring the science, may surprise you.

UN IPCC: “… greenhouse gases have unequivocally caused global warming”

The United Nation’s (UN’s) influential Intergovernmental Panel on Climate Change (IPCC) is tasked with periodically assessing the results of scientific publications and climate modeling. The UN IPCC’s Synthesis Report of the Sixth Assessment Report (AR6),[1] published in 2023, provides the IPCC’s assessment of global warming and climate change in plain language. The report consists of two documents: the 42-page Summary for Policy Makers and the 85-page Longer Report that supplements the Summary with further details. The claims and predictions in the Synthesis Report are often cited and quoted by government officials and popular media.

The UN’s Synthesis Report claims that “Human activities, principally through emissions of greenhouse gases, [2] have unequivocally caused global warming…” CO2 is the greenhouse gas thought to be the principal cause of global warming. The report points to the coincidence of rising emissions of CO2 and rising atmospheric concentration of CO2 but offers no scientific evidence of a cause-and-effect relationship between the rising emissions and the rising concentrations.

The Synthesis Report further claims, without supporting evidence, that global warming and climate change can be mitigated or stopped by ending emissions of greenhouse gases emitted by human activities, especially CO2. Human activities that emit CO2 include using fossil fuels[3] to produce energy and chemicals, manufacturing cement to make concrete, and using land (mostly associated with food production). Fossil fuels are by far the largest source of CO2 emissions.[4]

How Scientists Disproved Claims that Fossil Fuels Caused Global Warming

Three physicists published a scientific paper (Skrabel et al, 2022)[5] that proved that fossil fuel emissions of CO2 are only a small fraction of total atmospheric CO2. The following paragraphs briefly summarize their methods and findings.

Earth’s atmosphere is slightly radioactive due to the natural presence of radioactive carbon-14 atoms contained in the molecules of atmospheric CO2. From 1750 to around 1900, the level of radioactivity did not change significantly. After about 1900, the level of radioactivity in Earth’s atmosphere gradually declined due to dilution by non-radioactive CO2 that was increasingly emitted by burning fossil fuels and manufacturing cement.[6]

The authors used measurements (recorded by other scientists) of atmospheric carbon-14 to calculate the dilution of radioactivity and the average annual concentration of non-radioactive CO2 in Earth’s atmosphere from 1750 to 2018. That concentration was compared to the total annual concentration of atmospheric CO2 provided by the US Energy Information Agency (EIA).

The authors calculated that in 2018, the atmospheric concentration of non-radioactive CO2 was only 11.55% of the total concentration of CO2. The authors estimated the average annual concentration and percentage concentration of non-radioactive CO2 back to 1750. Their paper documented the data and formulas used in calculating the results.

A Revision Based on New Data

In the original Skrabel et al publication, the authors acknowledged that carbon-14 had been added to the atmosphere by nuclear bomb tests in the 1950s and 1960s but estimated that the added bomb-test carbon-14 did not significantly distort the calculated amounts of non-radioactive CO2.

A letter from Schwartz et al (2022), in response to Skrabel et al, pointed to an alternative atmospheric carbon-14 data set that was charted in the letter. That chart is reproduced in Figure 1.

In Figure 1, the data points (dots) indicate measurements of the specific activity of carbon-14 radiation (in disintegrations per minute per gram of carbon) taken from the atmosphere and tree ring samples – a compilation of decades-long observations by several scientists. [7] Note that the specific activity spiked upward around 1955 due to the nuclear bomb tests in the atmosphere. The specific activity has dissipated, but only by about half of peak activity in 2018.

Figure 1. Atmospheric Carbon-14 Radiation. Schwarz et al 2022

The red dots show measurements of the specific activity of carbon-14 radiation before the initiation of bomb tests. The cyan-colored curve is a “No bombs” extrapolation of the pre-bomb-test data that simulates atmospheric carbon-14 radiation without distortion by residual bomb-test-related carbon-14. The original Skrable et al data set is charted in Figure 1 as a brown curve.

A comparison of the two data sets shows that the specific activities originally used by Skrable et al were about 14% higher than those provided by Schwartz et al. Notice that both curves slope downward in the 20th century as the non-radioactive CO2 progressively diluted the radioactivity of the atmosphere. It is this dilution that Skrable et al exploited algebraically to calculate the concentration of non-radioactive CO2.

Three months after Skrable et al was published, the authors published a supplementary document[8] that applied the original logic and equations to the Schwartz et al data set, provided derivations of the equations, and provided example calculations. The revised calculations found that in 2018, the non-radioactive CO2 comprised 10% (instead of 11.55%) of total atmospheric CO2. (The fossil-fuel-emitted CO2 is about 96% of the total non-radioactive CO2.)

Since fossil-fuel-emitted CO2 contributed less than 10% to total atmospheric CO2 by 2018, banning CO2 emissions could not have significantly hindered global warming.

The claims that fossil fuel emissions of CO2 are the principal cause of global warming have been disproved by straightforward calculations using two different data sets. The role of fossil-fuel-emitted CO2 in rising atmospheric CO2 and global warming is marginal at best. The principal cause of rising atmospheric CO2 and rising global temperature remains to be determined.

Evaluating the Evidence

Non-scientists can readily determine if claims are made without supporting evidence. We should always be wary of unsubstantiated claims (even in the UN’s Synthesis Report), especially when unsubstantiated claims are being used to justify a coercive public policy. If we don’t demand supporting evidence, we can be led to believe and accept anything.

On the other hand, it is not easy for non-scientists to judge the credibility of scientific evidence when provided. But if we do not try to assess the credibility of scientific evidence, we remain vulnerable to false claims and unjustified coercive public policies. However, we can assess how the evidence is received by other scientists:

  • The UN’s Synthesis Report did not report any evidence that contradicts Skrable et al.
  • The publication was peer-reviewed by three other scientists before publication.
  • Six different critiques of the original paper were published by scientists. One, Schwartz et al, provided an alternative data set that corrected for the radiation from nuclear bomb tests. That data set was adopted by Skrable et al in a revised publication. The five other critiques mostly complained that the findings conflicted with various claims about fossil fuels and global warming but did not provide supporting evidence for their claims.
  • The logic and calculations used by the authors were explained in detail in the original and the revised publications. The derivations and formulas use simple algebra that any trained physical scientist could understand and critique. Yet no scientist has specifically criticized the logic, methods, or calculations in the two publications by Skrable et al. Nor have scientists criticized the Schwartz et al and EIA data sets used in the revision.

There may be further revisions to these findings. Refinements and revisions to scientific discoveries often occur, especially when new or improved data becomes available. That’s how science progresses. Even Isaac Newton’s brilliant Law of Gravity was revised by Albert Einstein centuries after Newton published the Law of Gravity.

Nevertheless, we can be reasonably confident that replacing fossil energy with alternative energy will only marginally hinder the future rise of atmospheric CO2 and global temperature.

The Cost of Accepting a Disproved Claim

When we see evidence that disproves widely accepted claims, it may seem easier to just ignore the evidence. But, in this case, ignoring the evidence will be costly. That’s because the disproved claim that “Human activities, principally through emissions of greenhouse gases, have unequivocally caused global warming…” is being used by climate alarmists and the green energy industry to justify the coerced replacement of fossil energy with electricity generated by wind turbines and solar panels. But this energy policy will lead to economic hardship or even economic disaster.

A major problem with wind and solar generation is that they are very unreliable. The electric output can drop to zero at any time. At present, unreliable wind and solar electric output in the US are mostly backed up by existing reliable fossil, hydroelectric, geothermal, and nuclear generation. Yet environmental climate activists and some regulators are trying to force the complete elimination of fossil generation. In California, even reliable nuclear and large hydroelectric facilities have been targeted for replacement by wind and solar generation.

To the extent that reliable generation is retired without reliable replacements, Americans will be left with an extremely unreliable supply of electricity, even electric grid failures.

Consider California, which has been relying upon large additions of wind and solar generation to replace fossil and nuclear generation. As a result, California began experiencing rolling blackouts a couple of years ago. During one power shortage, the State even pleaded with EV owners to delay charging their EVs. Now California has reversed the retirement of three large natural gas-fueled generating plants (Ormond Beach, Redondo Beach, and Huntington Beach) and a nuclear-generating plant (Diablo Canyon). The California legislature has also ordered the construction of four new fossil-generating plants to serve as an emergency reserve. [9]

Backing Up Wind and Solar with Storage Batteries

Climate activists often claim that wind and solar can be made dependable if they are backed up with electric storage batteries instead of fossil and nuclear generation. If you wonder why California has rescued retiring fossil and nuclear generation, instead of installing storage battery backup, the reason is probably the unbearable cost of storage battery backup.

Professional Engineer Ken Gregory published a paper in 2022 showing the details of his credible estimate of the capital cost of providing wind, solar, and backup batteries to replace all fossil generation in the US, converting most of the US fossil energy supply to non-fossil-generated electricity supply (except aviation and shipping fuels), during the year 2020.[10]

Using the EIA’s costing rates for batteries, Gregory estimated the capital cost to electrify the US in 2020 to be $290 trillion, of which $267.5 trillion is for battery storage alone. That is thirteen times the US 2020 GDP and over $1 million per US adult.

A major cost factor is that a massive supply of electric energy must be stored to replace seasonal weaknesses in the output of wind and solar as charted in Figure 2.

Figure 2. Required US Seasonal Battery Storage. Ken Gregory 2022

Figure 2 shows the calculated amount of daily storage that would be required in the US to back up wind and solar generation in the absence of fossil fuel generation. The calculation used the same hourly wind and solar production profile that occurred in 2019 and 2020 but was multiplied proportionately higher to simulate the added generating capacity required to replace the fossil-fueled generation that existed nationwide in 2019 and 2020.

Another major cost factor is the huge additional electric energy storage required to back up the added wind and solar generation required to electrify ground transportation and heating.

These costs will be so intolerable that electrification may eventually be abandoned when the cost burden begins to become apparent to the American public. Yet until then, considerable economic harm and inconvenience can be done by uncaring or ignorant government officials and tolerated by an apathetic or ignorant American public.

There are other dependable, zero-carbon replacements for fossil-fueled electric generation such as nuclear, hydroelectric, and geothermal generation. However, new facilities using these technologies are extremely difficult to permit and are not at all cost-competitive with fossil-fueled generation without subsidies. In the future, these technologies might become more competitive and more available, but only if the laws and regulations that currently constrain their use are reformed.

Some advocate the use of hydrogen to replace fossil-fueled heating or ground transportation. The most affordable hydrogen is made from natural gas – not a zero-carbon fuel and not competitive with natural gas for heating purposes. Green (zero-carbon) hydrogen can be produced using electricity that is generated by a zero-carbon technology. But green hydrogen must be massively subsidized by governments to compete in US energy markets.

Replacing fossil energy with another reliable energy is prohibitively expensive. Given the cost and the findings of Skrabel et al, replacing affordable fossil energy is irrational.

The World Is Not Replacing Fossil Fuels

Americans have been inundated with unproven global warming claims. So, they might expect that replacing fossil fuels is inevitable. If so, they should know that most of the world has rejected the UN’s decades-long campaign to persuade the world to replace fossil energy with green energy. Despite over two dozen UN global climate conferences (COP), the Kyoto Protocol, and the Paris Agreement, the world has not significantly curtailed atmospheric CO2. Atmospheric CO2 concentration increased from about 330 ppm in 1980 to about 415 ppm in 2020.[11] See Figure 3.

The US contribution of fossil-fuel-emitted CO2 is about 13% of the world’s total fossil-fuel-emitted CO2, which, in 2018, contributed less than 10% of total atmospheric CO2. That’s a fraction of a fraction – about 1.3% in 2018 – an insignificant contribution to atmospheric CO2 and global warming. So, replacing reliable and affordable fossil energy in the US, when most of the world embraces fossil energy, is doubly foolish.

Global emissions of fossil fuels are likely to continue increasing for a long time, no matter what economic harm Americans mistakenly inflict upon themselves to replace fossil fuels.

Figure 3: 30 Years of the UN’s Failed Climate Campaign11


Scientists have proved that CO2 emitted by producing fossil energy and cement made only a minor contribution to the CO2 in the atmosphere between 1750 and 2018. Whatever caused slightly more than 1°C of global warming during that period, the warming could not have been caused by the production of fossil energy and cement. Replacing fossil energy cannot stop global warming.

Replacing fossil-fueled electric generation with wind and solar alone will lead to electric grid failures. Adding backup batteries will probably cost over $1 million per American adult. At this time, no reliable alternative can compete with fossil energy without massive government subsidies.

Such costs may explain why most of the world is ignoring the UN’s 30-year campaign to replace fossil energy with green energy. Worldwide rejection of green energy policies further guarantees that replacing fossil energy in the US will not hinder rising atmospheric CO2 or global warming.

Americans should not feel guilty about enjoying affordable, reliable fossil energy. We should thank the scientists and their publisher for their integrity, intelligence, and courage to publish science that challenges conventional “wisdom.” We should also thank our much-maligned fossil fuel producers. Finally, let’s demand an end to futile and costly green energy policies.


[1] Synthesis Report for AR6: Synthesis Report — IPCC consisting of the Summary of Policy Makers     (IPCC_AR6_SYR_SPM.pdf) and the Longer Report (IPCC_AR6_SYR_LongerReport.pdf)

[2] Greenhouse gases: The five most important greenhouse gases are water vapor, carbon dioxide, ozone, nitrous oxide, and methane or H2O, CO2, O3, N2O, and CH4 respectively.

[3] Fossil fuels: Fossil fuels include coal, natural gas, propane, butane, petroleum, and various petroleum refinery products such as gasoline, diesel fuel, and jet fuel. Thousands of non-fuel products are also made from fossil fuels, including chemicals, paints, plastics, synthetic fabrics, cosmetics, pharmaceuticals, and fertilizers for food crops.

[4] Greenhouse emissions by sector: Greenhouse emissions are charted as % of global total CO2eq by sector.

[5] Skrabel et al: World Atmospheric CO2, Its 14C Specific Activity, Non-fossil Component, Anthropogenic Fossil Component, and Emissions (1750–2018) authored by three Professors Emeritus of Physics at the University of Connecticut (Dr. Kenneth Skrable, Dr. George Chabot, and Dr. Clayton French). The authors declared that they have no conflict of interest.
World Atmospheric CO2, Its 14C Specific Activity, Non-fossil…: Health Physics (

[6] Carbon-14: Carbon-14 (14C) atoms are continuously produced in the atmosphere by the interaction of atmospheric nitrogen with cosmic rays. However, fossil fuels were produced millions of years before the 5,730-year half-life of carbon-14. Any carbon-14 in fossil fuels decayed to a stable isotope long ago. Consequently, fossil fuels are devoid of carbon-14 radiation. Cement is also devoid of carbon-14 radiation because it is made by heating limestone (CaCO3) which was also formed long ago. Fossil fuels account for about 96% of non-radioactive CO2. See End Note 4.

[7] Historical observations of atmospheric carbon-14: Carbon-14 (radiocarbon) has long been used by scientists in radiocarbon dating of once-living fossils. To serve this purpose, there has been a considerable effort by scientists over the years to quantify the natural background radiation from carbon-14 in the atmosphere. To go back in time when no air samples were taken and evaluated, scientists have sampled long-lived trees to estimate the atmospheric concentration of carbon-14 which was taken into the trees by the normal process of photosynthesis. Counting the rings in cross-sections of tree trunks (one for each year of life) allows the radiation to be dated. Scientists also used borings through annual layers of glacial ice to determine atmospheric carbon-14 concentrations going even further back in time.

[8] Supplement to Skrable et al: Derivation of equations and example calculations of the components of CO2. Revision of May 11, 2022, based on a “No bombs” scenario.

[9] California power shortage:

[10] Cost of storage battery backup: The Cost of Net Zero Electrification of the U.S.A by Ken Gregory, P.Eng. 2022  Replacing fossil fuels for electric generation, ground transportation and space heating would save roughly $791 billion/year in fossil fuel costs in 2023. This is financially equivalent to an $8.38 trillion present value (capital cost), assuming the annual cost grows at 2%/year and is discounted at a 7%/year cost of capital for 15 years).

[11] 30 years of the UN’s failed climate campaign: The Figure 3 chart of atmospheric CO2 concentration was produced by the Scripps Institute of Oceanography and the National Oceanic and Atmospheric Administration (NOAA). The Global Warming Policy Foundation (GWPF) added its logo and the UN policy conferences and agreements to the Scripps-NOAA chart.



Richard Batey received a Bachelor of Science degree (Physics) from Texas A&M University and enjoyed a lengthy career in the electric utility power generation and transmission industry. Rich receives no compensation or other benefits from any employers or sponsors.

The views expressed above represent those of the author and do not necessarily represent the views of the editors and publishers of Capitalism Magazine. Capitalism Magazine sometimes publishes articles we disagree with because we think the article provides information, or a contrasting point of view, that may be of value to our readers.

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