Past holds the key to future
Scientists are exploring every corner of the planet for prehistoric clues to understand the future of monsoon
They say that history has a habit of repeating itself. Climatologists and scientists studying the history of South Asian monsoon must hope that the adage holds true, because if it does, their studies could give insights into the future of monsoon.
Faced with the unpredictability of our monsoons and baffled by the periodic revelations of complexities that are possibly influencing its evolution, researchers have turned to palaeoclimatology for clues to how the monsoon might react to climate change. Palaeoclimatology uses indicators stored in geological archives, or proxies, to reconstruct climatic patterns from prehistoric times. These are decoded using dating processes that can decipher data recorded several million years ago.
“Some of these proxies include chemical, isotopic and biogenic composition of sediments which provide information on past temperatures, sea level variation and monsoon variability,” says Ravi Bhushan, researcher at the Physical Research Laboratory (prl) in Ahmedabad,Gujarat.
Working on the assumption that basic processes dictating climatic patterns have remained constant through the ages, historic data holds undeniable value in understanding the current trajectories of monsoon.The data can be used to recreate long-term climate patterns, and by seeing where the current monsoon is located on the geological scale, we can speculate what trajectory it is going to take.
This data is found in naturally formed archives such as ice cores, tree rings, sediments from water bodies and cave deposits. Researchers have been exploring these geological sources for information on prehistoric monsoon:
These can provide information about climate in the most recent past. A team studying palaeoclimatic trends in monsoon at the Indian Institute of Technology-Mumbai (iit-m) has used cross-sections of tree trunks to reconstruct weather patterns up to 2,000 years ago. H P Borgaonkar, lead scientist of the team, says, “The characteristics of each ring reflects climatic conditions of the previous year. For example, narrow rings indicate extreme weather such as droughts. The decadal epochs of monsoons—the 31 year cycles of alternate excessive and deficient phases that we are observing