A group of scientists from IIT Kharagpur and Academia Sinica, Taipei has certainly found proof of very high annual rainfall in the course of the catastrophic volcanism that fashioned the Deccan Traps in India about 66 million years again. They used a brand new approach — Nanoscale Secondary Ion Mass Spectrometry — to analyse three isotopes of oxygen (Oxygen-16,17, and 18) in fossil timber of the Cretaceous interval and measure the isotopic composition of the lake water derived from rainfall.
The depleted values of the oxygen isotopes counsel a better tropical rainfall (1,600 mm per 12 months) in India in the course of the terminal Cretaceous interval. The enhance in rainfall and its waning within the early Palaeocene intently follows change in palaeo-atmospheric (paleo carbon dioxide) suggesting a doable underlying hyperlink. Results have been revealed within the Journal of Chemical Geology.
“The available records of the atmospheric carbon dioxide concentration and temperature over both land and ocean during the time of Deccan Trap eruption were analysed. Deccan trap lavas were erupting spewing huge amount of carbon dioxide thus increasing the then atmospheric carbon dioxide concentration to as high as 1,000 ppm (parts per million),” Prof. Anindya Sarkar from the Department of Geology and Geophysics at IIT Kharagpur and corresponding creator of the paper mentioned in a launch.
“Excepting the arid/semi‐arid regions, the modern annual rainfall over large parts of peninsular India on an average is about 1,000‐1,200 mm. Our data suggested that these fossil trees recorded 1,800‐1,900 mm rainfall per year . This is exactly what the IPCC predicts in case of a future extreme 4 degree C warming of the planet,” mentioned Prof. Sourendra Bhattacharya, a co‐creator of the paper.
Fossil gas emission has elevated carbon dioxide from a pre‐industrial stage of 280 ppm to about 420 ppm in 2023. Climate fashions counsel {that a} doubling of carbon dioxide will intensify the atmospheric circulation and consequently the rainfall. The 2023 AR6 report by the Intergovernmental Panel on Climate Change (IPCC) warns if the carbon dioxide emission and world warming proceed unabated, annual wettest day precipitation will enhance by manifold throughout all continents. Monsoon rainfall related to tropical cyclones over India can even enhance by 40%. While these predictions are made via local weather fashions, they will solely be examined by finding out the rainfall document prior to now when the earth went via a pure warming part attributable to high carbon dioxide emission.
