Past terrestrial hydroclimate sensitivity controlled by Earth system feedbacks
International audience Despite tectonic conditions and atmospheric CO 2 levels (pCO 2) similar to those of presentday, geological reconstructions from the mid-Pliocene (3.3-3.0 Ma) document high lake levels in the Sahel and mesic conditions in subtropical Eurasia, suggesting drastic reorganizations...
Published in: | Nature Communications |
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Main Authors: | , , , , , , , , , , , , , , , , , , , , , , , , |
Other Authors: | , , , , , , , , , , , , , , , , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
HAL CCSD
2022
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Subjects: | |
Online Access: | https://hal.science/hal-03620581 https://hal.science/hal-03620581/document https://hal.science/hal-03620581/file/s41467-022-28814-7.pdf https://doi.org/10.1038/s41467-022-28814-7 |
Summary: | International audience Despite tectonic conditions and atmospheric CO 2 levels (pCO 2) similar to those of presentday, geological reconstructions from the mid-Pliocene (3.3-3.0 Ma) document high lake levels in the Sahel and mesic conditions in subtropical Eurasia, suggesting drastic reorganizations of subtropical terrestrial hydroclimate during this interval. Here, using a compilation of proxy data and multi-model paleoclimate simulations, we show that the mid-Pliocene hydroclimate state is not driven by direct CO 2 radiative forcing but by a loss of northern highlatitude ice sheets and continental greening. These ice sheet and vegetation changes are long-term Earth system feedbacks to elevated pCO 2. Further, the moist conditions in the Sahel and subtropical Eurasia during the mid-Pliocene are a product of enhanced tropospheric humidity and a stationary wave response to the surface warming pattern, which varies strongly with land cover changes. These findings highlight the potential for amplified terrestrial hydroclimate responses over long timescales to a sustained CO 2 forcing. |
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