The planet\u2019s atmosphere held more water vapour in August than any other month on record, further increasing the risk of extreme heat and rainfall around the world, according to Europe\u2019s climate change service.<\/p>\n
Climate scientists said global heating was a contributor to the record because a warmer atmosphere can hold more water, and the historic El Ni\u00f1o in the Pacific Ocean was also likely pushing water vapour levels up.<\/p>\n
According to the Copernicus Climate Change Service (C3S), the amount of water vapour in the atmosphere through August was 27.35 kg per square metre, beating the previous record from July 2024 by 0.04 kg m\u00b2.<\/p>\n
The value describes how much water vapour is in a column of air sitting above a square metre of the Earth\u2019s surface, extending up through the atmosphere.<\/p>\n
The 0.04 kg m\u00b2 increase on the previous record, one climate scientist calculated, was the equivalent of about 20 trillion litres of additional water, or 20 cubes of water, each a kilometre wide, high and deep.<\/p>\n
Global monthly total column water vapour from 1979 to 2026. Illustration: C3S\/ECMWF<\/p>\n
Dr Julien Nicolas, senior scientist at C3S, said water vapour was estimated in its ERA5 dataset by combining humidity measurements from satellites, weather balloons and other sources with a weather model. The water vapour estimates go back to 1979.<\/p>\n
August was also the planet\u2019s joint hottest month on the ERA5 dataset going back to 1940, and the hottest according to the US government\u2019s National Oceanic and Atmospheric Administration<\/a> dataset that starts in 1850.<\/p>\n Nicolas said the water vapour record was \u201cconsistent with the record high global temperature in August\u201d and said \u201cwarmer air can hold about 7% more water vapour per degree of [global] warming\u201d.<\/p>\n He said the tropical oceans were a major source of the water vapour.<\/p>\n \u201cThe exceptionally high sea surface temperatures seen across these regions in August, partly linked to the presence and strengthening of El Ni\u00f1o conditions, increased evaporation and were likely an important contributor to the record-high global water vapour value.\u201d<\/p>\n He said rising water vapour levels could increase the risk of intense rainfall, including from cyclones, and give extra energy to storms \u201cbecause heat is released when water vapour condenses into cloud droplets, potentially helping to intensify them\u201d.<\/p>\n Map of the world showing precipitable water in August 2026<\/a><\/p>\n The current El Ni\u00f1o climate pattern in the tropical Pacific is forecast to be the strongest on record<\/a> and climate scientists predict it could push global temperatures to record levels next year.<\/p>\n Provisional analysis by Australian scientists has found the expected record peak ocean temperatures in the Pacific that are a marker of the El Ni\u00f1o were being made six times more likely because of global heating.<\/p>\n