# Detecting anthropogenically induced changes in extreme and seasonal evapotranspiration observations

## TL;DR

This study finds that human-caused climate change is making high evapotranspiration events more common, increasing the risk of sudden droughts.

## Contribution

The study provides evidence that extreme evapotranspiration events are intensifying due to anthropogenic climate change.

## Key findings

- High evapotranspiration extremes are increasing due to anthropogenic climate change.
- Seasonal mean evapotranspiration shows mixed changes regionally from 1980 to 2023.
- Regions with strong extreme evapotranspiration trends face higher flash drought risks.

## Abstract

Increasing temperature and radiation drive an increase in evaporative demand. However, it is still uncertain whether the increase in demand has led to an increase in evapotranspiration (ET) in observational products, as this increase is at odds with a limited water supply over land. Here, we examine changes in high ET extremes and seasonal mean ET using climate models as well as observational data. High ET extremes are driven by periods with high incoming surface radiation and temperatures. In line with physical understanding, these events are intensified by anthropogenic climate change. We detect robust changes in extreme and seasonal ET in two observational data sets. Regionally, seasonal mean ET shows mixed increases and decreases from 1980 to 2023, while extreme ET universally increases or shows no significant change. Although the drivers for these changes can vary regionally, we expect that regions with strong extreme ET trends are at increased risk of flash droughts.

High evapotranspiration events are becoming more frequent because of anthropogenic climate change. This study shows robust increases in those events across many regions, indicating faster land drying and a growing risk of rapidly developing droughts.