By Dr Arvind Kumar
Many ecologists believe the sea will be devoid of fish and other large marine organisms sometime in the 2040s. Burning of fossil fuels results in release of carbon dioxide (CO2) into the atmosphere. The oceans act as an enormous carbon ‘sink’ which absorbs as much as 1/3rd of the released carbon dioxide. So the CO2 is no longer acting as a greenhouse gas in the atmosphere, but unfortunately, the problem of dealing with the excess gas has been shifted from the air to the oceans. The oceans are becoming more acidic as a result. In other words, through a natural process, the ocean becomes a giant waste dump for fossil fuel emissions.
The ocean’s interaction with CO2 mitigates some climate effects of the gas. The atmospheric CO2 concentration is almost 390 parts per million (ppm), but it would be even higher if the oceans didn’t soak up 30 million tons of the gas every day. The world’s seas have absorbed roughly one third of all CO2 released by human activities. This ‘sink’ reduces global warming—but at the expense of acidifying the sea. Robert H. Byrne of the University of South Florida has shown that in just the past 15 years, acidity has increased 6 percent in the upper 100 meters of the Pacific Ocean from Hawaii to Alaska. Across the planet, the average pH of the ocean’s surface layer has declined 0.12 unit, to approximately 8.1, since the beginning of the industrial revolution.
Left unchecked, CO2 levels are likely to create a very different ocean, one never experienced by modern species. Adaptation is even more unlikely because the effects of acidification and the other struggles creatures face.
