Arpita Samanta , Melinda Kumar Bera , Subir Bera , Fred J. Longstaffe , Shubhabrata Paul , Kishor Kumar , Anindya Sarkar
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引用次数: 0
Abstract
Under rising anthropogenic CO2, the future of the tropical climate states and the response of the biosphere, specifically the fate of the tropical rainforest (TRF), is uncertain. Therefore, deep-time climate proxy records and model simulations are being extensively utilized to understand the possible response of the TRF community during extreme climate states. However, comprehensive climate-TRF proxy data from the tropical/equatorial region for the paleo-global warming episodes, e.g., Late Paleocene – Early Eocene interval (∼56 to 51 Ma, encompassing transient hyperthermal events like Paleocene-Eocene Thermal Maximum [PETM], Eocene Thermal Maximum2 [ETM2]/H1/ Eocene Layer of Mysterious Origin [ELMO], H2, I1, and I2), are very limited and create difficulties in the validation of simulated results. Here we present long-term land surface temperature and precipitation (δ2H and δ18O of pedogenic clay mineral-derived) and TRF diversity (palynology) data from a paleo-equatorial region, spanning the ∼56 to 51 Ma interval. Present data suggest that the hydrological response to global warming was not temporally uniform in the paleo-equatorial land. While a significantly increased rainfall buffered the terrestrial temperature during the PETM, an insignificant increase in precipitation and negligible temperature lowering can be observed during the ETM2 hyperthermal event. However, the climate system's response during the other Early Eocene hyperthermals, i.e., H2, I1, and I2, was very similar to the PETM. Despite these small aberrations, the long-term average equatorial land surface temperature (27 ± 4 °C) during the Early Eocene greenhouse episode remained very similar to the modern equatorial temperature (28–30 °C). Rainfall proxy and plant diversity data suggest that the precipitation aided TRFs' resilience and proliferation, possibly through temperature buffering, during this paleo-greenhouse episode.
期刊介绍:
The objective of the journal Global and Planetary Change is to provide a multi-disciplinary overview of the processes taking place in the Earth System and involved in planetary change over time. The journal focuses on records of the past and current state of the earth system, and future scenarios , and their link to global environmental change. Regional or process-oriented studies are welcome if they discuss global implications. Topics include, but are not limited to, changes in the dynamics and composition of the atmosphere, oceans and cryosphere, as well as climate change, sea level variation, observations/modelling of Earth processes from deep to (near-)surface and their coupling, global ecology, biogeography and the resilience/thresholds in ecosystems.
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