Accurate quantification of global land evapotranspiration is necessary for understanding variability in the global water cycle, which is expected to intensify under climate change^1,2,3. Current global evapotranspiration products are derived from a variety of sources, including models^4,5, remote sensing^6,7 and in situ observations^8,9,10. However, existing approaches contain extensive uncertainties; for example, relating to model structure or the upscaling of observations to a global level¹¹. As a result, variability and trends in global evapotranspiration remain unclear¹². Here we show that global land evapotranspiration increased by 10 ± 2 per cent between 2003 and 2019, and that land precipitation is increasingly partitioned into evapotranspiration rather than runoff. Our results are based on an independent water-balance ensemble time series of global land evapotranspiration and the corresponding uncertainty distribution, using data from the Gravity Recovery and Climate Experiment (GRACE) and GRACE-Follow On (GRACE-FO) satellites¹³. Variability in global land evapotranspiration is positively correlated with El Niño–Southern Oscillation. The main driver of the trend, however, is increasing land temperature. Our findings provide an observational constraint on global land evapotranspiration, and are consistent with the hypothesis that global evapotranspiration should increase in a warming climate.

全球陆地蒸散的准确量化对于了解全球水循环的可变性是必要的，预计在气候变化^1,2,3下会加剧。目前的全球蒸散产品来源于多种来源，包括模型^4,5、遥感^6,7和原位观测^8,9,10。但是，现有方法包含大量不确定性；例如，与模型结构或将观测值提升到全球水平¹¹有关。因此，全球蒸发量的变化和趋势仍不清楚¹². 在这里，我们表明全球陆地蒸发蒸腾量在 2003 年至 2019 年期间增加了 10 ± 2%，并且陆地降水越来越多地被划分为蒸发蒸腾量而不是径流。我们的结果基于全球陆地蒸散的独立水平衡集合时间序列和相应的不确定性分布，使用来自重力恢复和气候实验 (GRACE) 和 GRACE-Follow On (GRACE-FO) 卫星的数据¹³. 全球陆地蒸散量的变化与厄尔尼诺-南方涛动呈正相关。然而，这一趋势的主要驱动因素是土地温度升高。我们的研究结果为全球陆地蒸发蒸腾提供了一个观测约束，并且与全球蒸发蒸腾应在气候变暖中增加的假设一致。