At 399 ppm, India matches the world in atmospheric carbon dioxide levels

The first-ever picture of atmospheric carbon dioxide concentration over India shows that it is way above the safety mark and in line with what has been observed in other parts of the world.

Since the 1950s, scientists have been measuring the concentration of CO2 in the atmosphere at observatories such as Mauna Loa in Hawaii and since the 1990s, using satellite images.

Beyond 350 molecules

It’s generally been agreed that for every million gas molecules in the atmosphere, anything beyond 350 carbon dioxide molecules, is considered unsafe. These concentrations are likely to trap enough heat to trigger extreme climate events the world over and it would become progressively harder, and costlier, to suck out the excessive CO2. In 2015, the global average was 400 ppm, according to reports from Mauna Loa. In India, that year, according to a report published in the latest issue of Current Science, the average CO2 level was 399 parts per million (ppm).

However, at Cape Rama, a coastal station in Goa, where CO2 levels have been monitored for over a decade, the level shot up to 408 ppm. The findings, based on readings from the Orbiting Carbon Observatory-2 (OCO-2) — a NASA satellite to monitor the environment — reveal that pockets of Madhya Pradesh, Uttar Pradesh and Himachal Pradesh saw CO2 concentrations hover much higher between 405 ppm and 410 ppm.

Southern India and the western coast saw concentrations between 395 ppm and 400 ppm while the central and northern regions registered between 400 and 405 ppm.

Multiple causes

“... It is difficult to precisely attribute the causes for such higher values; however, there could be a few possible reasons like lack of a CO2 sink, point sources like forest fires or biomass burning or an urban source, and gaseous transport from neighbouring regions based on prevailing weather conditions,” say authors Abha Chhabra and Ankit Gohel in their paper. The scientists are affiliated with the Space Applications Centre of ISRO. Generally, CO2 levels increase slightly during winter due to reduced vegetation but for this study, the observations were made from March to July in 2015.

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Printable version | Nov 29, 2021 9:06:57 PM | https://www.thehindu.com/sci-tech/energy-and-environment/at-399-ppm-india-matches-the-world-in-atmospheric-carbon-dioxide-levels/article19150785.ece

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