Global warming: Some rainforests may take heat stress and survive, study suggests

Different climate models suggest that a projected doubling of CO2 will intensify the atmospheric circulation and consequently the rainfall.

- RITWIK MUKHERJEE

Nature already did experiments in the past that have lessons for the world to learn. Many experts believe that the climate change due to such fast rate of global warming is now irreversible and collapse of rainforest or ocean biosphere is just imminent. But is there any hope? At least one recent study suggests that there may be some hope. At least the rainforest may take the heat stress and survive.

A team of scientists from IIT Kharagpur, Calcutta University and University of Western Ontario have studied detail records of the tropical rain forests (TRF) in sediments from Vastan coal mines of Gujarat deposited in coastal lagoons around 56 million years back. The study found a large anomaly in carbon isotopes exactly at 56 million year. This was such a characteristic signal for a super greenhouse globe with very high atmospheric CO2. The hydrogen and oxygen isotope compositions in clays depend on land temperature and amount of rainfall and act as snapshots of past climate. Likewise, the isotopes in fossil teeth record the history of what water animals drank. As the CO2 began to increase, the land became abnormally hot- more than 400C. But to the scientists' surprise, they found that the temperature came down to nearly 300C during the later period, almost similar to today. The rainforest not only survived but also diversified during and after this global warming phase.