Deciphering the role of evapotranspiration in declining relative humidity trends over land
Abstract In recent decades, relative humidity over land has declined, driving increases in droughts and wildfires. Previous explanations attribute this trend to insufficient moisture advection from the ocean to sustain the current level, but this ignores atmospheric moisture supplied from terrestria...
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Nature Portfolio
2025-02-01
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| Series: | Communications Earth & Environment |
| Online Access: | https://doi.org/10.1038/s43247-025-02076-9 |
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| author | Yeonuk Kim Mark S. Johnson |
| author_facet | Yeonuk Kim Mark S. Johnson |
| author_sort | Yeonuk Kim |
| collection | DOAJ |
| description | Abstract In recent decades, relative humidity over land has declined, driving increases in droughts and wildfires. Previous explanations attribute this trend to insufficient moisture advection from the ocean to sustain the current level, but this ignores atmospheric moisture supplied from terrestrial evapotranspiration. Importantly, current state-of-the-art climate models continue to underestimate the observed relative humidity trend over land. Here, we show that changes in specific humidity over land relative to a given baseline, unaccounted for by ocean advection, are quantitatively equivalent to relative changes in evapotranspiration on a global scale. This finding is consistent across climate models and climate reanalysis datasets, despite discrepancies in evapotranspiration trends among them. Differences in evapotranspiration trends are identified as a prominent cause of the bias in relative humidity trend expressed in climate models. These results suggest that current climate models may overestimate evapotranspiration intensifications, leading to an underestimation of atmospheric drying, with critical implications for accurately predicting droughts, wildfires, and climate adaptation. |
| format | Article |
| id | doaj-art-49cffcd810d547f99b7fd038972d2ec5 |
| institution | DOAJ |
| issn | 2662-4435 |
| language | English |
| publishDate | 2025-02-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Communications Earth & Environment |
| spelling | doaj-art-49cffcd810d547f99b7fd038972d2ec52025-08-20T02:43:11ZengNature PortfolioCommunications Earth & Environment2662-44352025-02-01611810.1038/s43247-025-02076-9Deciphering the role of evapotranspiration in declining relative humidity trends over landYeonuk Kim0Mark S. Johnson1Institute for Resources, Environment and Sustainability, University of British ColumbiaInstitute for Resources, Environment and Sustainability, University of British ColumbiaAbstract In recent decades, relative humidity over land has declined, driving increases in droughts and wildfires. Previous explanations attribute this trend to insufficient moisture advection from the ocean to sustain the current level, but this ignores atmospheric moisture supplied from terrestrial evapotranspiration. Importantly, current state-of-the-art climate models continue to underestimate the observed relative humidity trend over land. Here, we show that changes in specific humidity over land relative to a given baseline, unaccounted for by ocean advection, are quantitatively equivalent to relative changes in evapotranspiration on a global scale. This finding is consistent across climate models and climate reanalysis datasets, despite discrepancies in evapotranspiration trends among them. Differences in evapotranspiration trends are identified as a prominent cause of the bias in relative humidity trend expressed in climate models. These results suggest that current climate models may overestimate evapotranspiration intensifications, leading to an underestimation of atmospheric drying, with critical implications for accurately predicting droughts, wildfires, and climate adaptation.https://doi.org/10.1038/s43247-025-02076-9 |
| spellingShingle | Yeonuk Kim Mark S. Johnson Deciphering the role of evapotranspiration in declining relative humidity trends over land Communications Earth & Environment |
| title | Deciphering the role of evapotranspiration in declining relative humidity trends over land |
| title_full | Deciphering the role of evapotranspiration in declining relative humidity trends over land |
| title_fullStr | Deciphering the role of evapotranspiration in declining relative humidity trends over land |
| title_full_unstemmed | Deciphering the role of evapotranspiration in declining relative humidity trends over land |
| title_short | Deciphering the role of evapotranspiration in declining relative humidity trends over land |
| title_sort | deciphering the role of evapotranspiration in declining relative humidity trends over land |
| url | https://doi.org/10.1038/s43247-025-02076-9 |
| work_keys_str_mv | AT yeonukkim decipheringtheroleofevapotranspirationindecliningrelativehumiditytrendsoverland AT marksjohnson decipheringtheroleofevapotranspirationindecliningrelativehumiditytrendsoverland |