Meghalaya cave may solve mysteries of climate change

Meghalaya cave may solve mysteries of climate change

Photo for representation only.

An ancient cave in Meghalaya provides the latest set of clues to scientists on the unlocking of the secrets of climate change with far-reaching implications.

By studying the last 50 years of growth of a stalagmite inside the Mawmluh cave, they found an unexpected connection between the quantity of winter rainfall received in northeast India and a set of climatic conditions seen in the Pacific.

The new research, scientists claim, would help understand how the pattern of northeast monsoon can change in future.

Incidentally, the northeast cave where the experiments were conducted in the same one that brought international fame to Meghalaya last year after a geological era was scientifically named as “Meghalayan Age” on the basis of studies carried out in that formation.

The cave has lots of stalagmites, a type of rock formation that rises from the floor. Stalagmites grow from water regularly dripping onto the floor of a cave and often build up regularly in one spot over time. When it is cut into half, one can see its growth history from the bottom where the oldest material is to the top where the youngest material is.

A three-member team from Vanderbilt University, USA and Ruhr University, Bochum in Germany extensively studied the Mawmluh stalagmites in details.

The Mawmluh cave is located on the southern margin of the Meghalaya Plateau 13.7 km from Mawsynram and 2.3km from Sohra (Cherrapunji), two villages that alternate for the title of the wettest place on the earth. The region receives 70–80% of its annual rainfall between June and September, averaging 8,342 mm of rainfall between 1901–2014.

The new research, however, sheds more light on the dry season rainfall that generally happens between October and December.

From the analysis of trace elements (calcium and magnesium), scientists reconstructed the history of the stalagmite, providing information about local changes in hydrology.

Comparisons of cave records and nearby rainfall data show that variations in dry season rainfall rather than the monsoon rains govern variations in trace element concentrations in the stalagmite and how the amount of variation changes from year to year.

“Our record documents relationships between stalagmite chemistry and rainfall in Meghalaya and other aspects of the climate system such as the Pacific Decadal Oscillation. The analysis suggests a link between two that can be useful for understanding how Meghalayan rainfall will change in the future,” team leader Jessica L Oster from Vanderbilt University told DH.

Understanding past dry season rainfall variability may help improve mediation strategies against drought before it impacts the rainiest place on earth, the researchers reported in the journal Scientific Reports.