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Record atmospheric water vapor levels

Updated 1 time since CLSTR started tracking revisions of this situation.

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2026-09-18 10:52 UTC → 2026-09-21 01:32 UTC · added ~~removed~~

Data from the Copernicus Climate Change Service (C3S) indicates that atmospheric water vapor reached a historic record high in August, surpassing the previous record set in July 2024. The average concentration of precipitable water—the total amount ~~reached~~ of vapor in an air column from the surface to the upper atmosphere—hit 27.35 ~~kilograms per cubic meter, representing~~ kg/m³, the highest value recorded since data collection began in 1979. This surge represents approximately 20 trillion additional liters of water distributed globally. Scientists attribute this ~~surge~~ increase to a feedback loop driven by global warming and high ocean temperatures, particularly in the tropical Pacific associated with El ~~Niño phenomenon.~~ Niño. Because warmer air can hold more moisture—specifically about 7% more for every one degree Celsius of temperature increase—the excess vapor ~~increases~~ acts as a potent greenhouse gas. This increased moisture can modify the intensity of meteorological phenomena, as the rising vapor eventually cools and condenses to form clouds and precipitation. Such levels increase the risk of extreme ~~weather. This includes~~ weather, including more intense rainfall, stronger storms, and more dangerous heat episodes, as the moisture provides energy to tropical cyclones and prevents nighttime temperatures from dropping during heatwaves. August was also identified as the hottest month on record according to NOAA datasets. Climatologist Andrew Dessler noted the unprecedented nature of the event, suggesting such levels may not have been seen in thousands or even 100,000 years.

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