During an era when Earth faced substantial warmth and atmospheric carbon dioxide levels surpassed 1000 ppmv approximately 50 million years ago, equatorial rainforests thrived, buoyed by abundant rainfall.
While the precise method by which flora endured such harsh circumstances remains inadequately understood, existing paleoclimate evidence from mid- and high latitudes suggests dramatic rainfall fluctuations around that time. Nevertheless, the quantification of terrestrial paleoclimate data from equatorial regions had remained unexplored until now. Scientists endeavor to delve into this paleoclimate data, aiming to unravel the enigmas surrounding survival amidst adverse conditions.
Researchers from the Birbal Sahni Institute of Palaeosciences (BSIP), an autonomous body under the Department of Science and Technology, have utilized plant proxies to quantify the terrestrial equatorial climate from around 50 million years ago. Through climate data reconstruction, they have unveiled a notably high precipitation level during that period. The scientists suggest that this heightened rainfall likely bolstered the water usage efficiency of plants, fostering resilience, enabling them to thrive and function amid exceedingly warm temperatures and heightened carbon dioxide concentrations of that time.
While it was previously understood that Earth experienced temperatures approximately 13°C warmer than present, coupled with carbon dioxide concentrations surpassing 1000 ppmv, leading to severe implications for the survival of forests in mid- and high-latitude regions due to hydrological cycle changes, equatorial forests remarkably persevered. A recent research publication in the journal Palaeogeography, Palaeoclimatology, Palaeoecology divulges, for the first time, the mechanism behind the survival of equatorial forests during this substantially warmer era than our current climate.
This study has also contributed to the development of a calibration file sourced from low-latitude regions. This calibration file is anticipated to be instrumental in quantifying long-term seasonal terrestrial climate changes. Deciphering the puzzle of rainforest survival—considered the world’s biodiversity hotspots—is pivotal in comprehending contemporary and future climatic and biotic shifts.