Greenhouse Gases Are Not the Only Problem

John F. Clauser, who won the 2022 Nobel Prize in Physics for work in quantum mechanics, has become one of the world’s best-known climate crisis skeptics. At major conferences in Seoul in June 2023 and in the United States that September, he argued that the climate crisis does not exist and that carbon dioxide has no connection to it.

Clauser attributed climate change instead to changes in cloud cover and the amount of sunlight clouds reflect. He argued that when greenhouse gases warm the surface, more low-level cumulus clouds form, reflecting sunlight and cooling the planet. In his view, this effect is 100 to 200 times stronger than carbon dioxide’s greenhouse effect, allowing Earth to quickly restore its equilibrium temperature. Mainstream meteorologists, however, have found that claim inconsistent with the facts.

The atmosphere’s greenhouse effect is dominated by water vapor, which accounts for 70 percent, while carbon dioxide contributes 20 percent and other greenhouse gases 10 percent. When human-emitted greenhouse gases raise global temperatures, the atmosphere holds more water vapor, intensifying the greenhouse effect. For the same mass, water vapor has a warming effect two to three times stronger than carbon dioxide. If human emissions are the trigger for the climate crisis, the author writes, water vapor is the bomb itself.

Clouds can counteract water vapor’s warming effect, but the amplifying effect is far stronger in reality. That means climate policy cannot focus only on cutting greenhouse-gas emissions. Any action that raises the planet’s temperature, including releasing heat or covering land with artificial structures, also increases atmospheric water vapor.

A focus on national emissions targets would make the transition to carbon-free energy central to climate policy. But the article argues that serious climate action must also restrain activities that raise temperatures. Nuclear power produces no carbon dioxide during electricity generation but releases large quantities of heated water. AI data centers consume vast amounts of electricity and cooling water, while expanding cities intensify the urban heat-island effect. After increasingly severe climate events around the world this summer, the author asks whether pursuing wealth through ever-greater energy use should remain a national priority, and calls on climate citizens to demand a change in course.