By Maarten van Swaay

The “climate change” narrative is collapsing like a house of cards. The list of failed predictions keeps growing: polar bears thrive, islands in the South Pacific grow instead of sinking, the Arctic sea passage is still iced up, snow still falls in London. The western edge of Antarctica is warming up, but not from climate change: some 100 volcanoes have been identified below the sea floor along the edge.

The public is becoming more skeptical, and policies follow the trend: COP30 has failed to agree on any significant statement; the United Nations has tabled its proposed scheme to impose a carbon tax on sea transport; Europe is walking back its plans for decarbonization; the auto industry is scaling back its plans for electric cars; the EPA is reviewing its endangerment decision that classifies CO₂ as a pollutant; New York has approved a gas pipeline; and Pennsylvania has withdrawn from the Regional Greenhouse Gas Initiative.

Perhaps the most telling change is the breaking of the hockey stick — the iconic symbol of global warming. How that came about is worth telling in some detail. The hockey stick became famous because it claimed to have removed the medieval warm period, leading to a slow and smoothly falling temperature through past millennium, followed by an abrupt steep rise.

In the Fall 2025 issue of American Scientist, Michael Mann and Peter Hotez express frustration that their work is being attacked by misinformation. Mr. Mann refers to his book The Hockey Stick, which has been subjected to an unending string of accusations of falsehood, and then reveals with some satisfaction that he has been awarded $1 million in defamation suits brought by him against National Review and CEI. He admits that some appeals are still pending at the time of writing.

Those appeals were decided in early 2025 — well before the fall issue of American Scientist went to print. But neither it nor the authors mention those decisions, even though — or maybe because — they cast a very different light on the hockey stick. The damage award was reduced from $1 million to $5,000, and Mr. Mann is now held responsible for the legal costs of the defense, about $500,000 for each suit. In other words, the defamation suits have been turned around: instead of being the victim of misinformation, Mr. Mann is now exposed as the source, and the hockey stick has been broken and can no longer be used as the sign of coming thermal runaway. The demise of the hockey stick is well described in a book by Andrew William Montford: The Hockey Stick Delusion.

Several reputable scientists, including Richard Lindzen, Willie Soon, Steven Koonin, and William Happer, have brought compelling arguments challenging the claim that atmospheric carbon can explain the temperature rise since the beginning of the industrial age, about 1850. Among other things, Mr. Lindzen notes that heat loss from earth cannot be from surface radiation, because almost all that radiation is absorbed, mostly by water vapor but also by other greenhouse gases. In this mixture, carbon dioxide plays at best a minor role: water vapor is by far the biggest contributor. That analysis makes the cult of carbon footprint untenable.

We see this development reflected in several places: Bill Gates has changed his stance as advocate for climate calamity to Bjorn Lomborg’s argument: it is far wiser to apply available funds to identified near-term issues than to squander them on avoidance of possible future changes. The EPA is reviewing its position that atmospheric carbon is a pollutant. Europe is walking back its ambitions to decarbonize. In the U.S., the auto industry is scaling back its production of electric vehicles.

Somewhat surprisingly, some very fundamental questions have been largely absent from the discussion: Is atmospheric carbon a driver of climate, or a consequence? If atmospheric carbon can indeed drive climate, can human efforts succeed in lowering its concentration? Can carbon from fossil fuels account for the observed rise in atmospheric carbon since their arrival about two centuries ago? The last of these questions can be addressed with a comparatively simple argument, which follows below:

In any single year, the atmosphere exchanges about ¼ of its total carbon content with “elsewhere” — vegetation, ocean absorption and release, organic decomposition, and other mechanisms. Those large flows into and out of the atmosphere must be in balance: over many millions of years, atmospheric carbon has fluctuated, but not by much. On a shorter scale, the record kept at Mauna Loa since 1958 clearly shows the effect of seasonal changes in the Northern Hemisphere. These data point to a well-maintained equilibrium between the atmosphere and “elsewhere.” Under that equilibrium, an increase of inflow from fossil fuels must be matched by a corresponding increase of outflow. Carbon from fossil fuels adds about 4% to the inflow into the atmosphere, so outflow must also increase by 4%. The only factor that controls outflow is atmospheric concentration, so we should expect a 4% increase in atmospheric carbon since the beginning of the industrial age.

An article in Wikipedia about atmospheric carbon exchange claims that about half of the yearly production of fossil carbon is retained by the atmosphere. There is good reason to suspect this claim: estimating it from the several exchange flows would require that the sum of those flows can be known to a precision of better than 1%. Far more likely, the retention estimate was made not from various flows but from the observed increase in atmospheric carbon. That would be a circular argument that tells us nothing about the influence of fossil carbon.

The observed increase in atmospheric carbon since two centuries ago is 50%: from 280 ppm (parts per million) to 420 ppm. Fossil fuels cannot even account for 10% of that increase, which must therefore be ascribed to other mechanisms. Unfortunately, the emphasis of the IPCC has been elsewhere, so we have little knowledge of the source of that increase. A plausible suggestion would be increased release of CO₂ by warming oceans. Under that suggestion, we would expect atmospheric carbon to follow temperature, with a substantial lag. That is consistent with what is known about the history of temperature and atmospheric carbon over the past million years or so.

We do not yet have much information about the causes of geologic temperature fluctuations, but several plausible causes have been suggested. The Milankowitch cycles relate to precession of Earth, cosmic dust clouds can affect the flow of solar radiation, and the sun itself can vary over geologic times.

In summary, the hockey stick — for decades the primary icon of global warming — has been shown to be a badly flawed model. It may well have served to hide the long list of predictions proved false.

The radiation balance of Earth is far more complex than was assumed. Atmospheric carbon content is not nearly as sensitive to fossil fuels as the “carbon footprint” narrative suggests. Moderate global warming should be welcomed rather than feared: far more people die from cold than from heat. The increase in atmospheric carbon is greening the world and will improve crop yields while lowering the demand for irrigation. Diverting the cost of futile climate mitigation to more profitable uses can allow vast improvements in life worldwide.

Maarten van Swaay is Professor Emeritus, Kansas State University.