But that can't be due to human activity. The only way for the atmosphere to hold more water vapour is if it gets warmer. So... Hang on, you're not saying...
In 2020 the researchers reported that these capsules could capture more than double their weight in water vapour from ambient air when relative humidity was below 60%.
It was one of the biggest eruptions since that of Mount Pinatubo in the Philippines in the 1990s and injected an estimated 146 million tonnes of water vapour into the stratosphere.
During colder times, the usual process of evaporation of the oceans goes out of balance, with the resulting precipitation of this water vapour accumulating as snow on expanding and deepening ice caps.