El Niño and global heating pushes water vapour in Earth’s atmosphere to record levels in August

Lightning during a storm in Frankfurt, Germany. One climate scientist said rising water vapour levels could increase the risk of intense rainfall, including from cyclones, and give extra energy to storms. Photograph: Matías Basualdo/ZUMA Press Wire/Shutterstock View image in fullscreen Lightning during a storm in Frankfurt, Germany. One climate scientist said rising water vapour levels could increase the risk of intense rainfall, including from cyclones, and give extra energy to storms. Photograph: Matías Basualdo/ZUMA Press Wire/Shutterstock El Niño and global heating pushes water vapour in Earth’s atmosphere to record levels in August Global heating contributes to record, with a warmer atmosphere able to hold more water, scientists say The planet’s 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’s climate change service. Climate scientists said global heating was a contributor to the record because a warmer atmosphere can hold more water, and the historic El Niño in the Pacific Ocean was also likely pushing water vapour levels up. 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 m². The value describes how much water vapour is in a column of air sitting above a square metre of the Earth’s surface, extending up through the atmosphere. The 0.04 kg m² 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. View image in fullscreen Global monthly total column water vapour from 1979 to 2026. Illustration: C3S/ECMWFDr Julien Nicolas, senior scientist at C3S, said water vapour was estimated in its ERA5 dataset , weather balloons and other sources with a weather model. The water vapour estimates go back to 1979. August was also the planet’s joint hottest month on the ERA5 dataset going back to 1940, and the hottest according to the US government’s National Oceanic and Atmospheric Administration dataset that starts in 1850. Nicolas said the water vapour record was “consistent with the record high global temperature in August” and said “warmer air can hold about 7% more water vapour per degree of [global] warming”. He said the tropical oceans were a major source of the water vapour. “The exceptionally high sea surface temperatures seen across these regions in August, partly linked to the presence and strengthening of El Niño conditions, increased evaporation and were likely an important contributor to the record-high global water vapour value.” He said rising water vapour levels could increase the risk of intense rainfall, including from cyclones, and give extra energy to storms “because heat is released when water vapour condenses into cloud droplets, potentially helping to intensify them”.