CO2 in the atmosphere exceeds 415 parts per million
For the first time in human history carbon dioxide in the atmosphere has topped 415 parts per million, reaching 415.26 parts per million, according to sensors at the Mauna Loa Observatory, a research outpost of the National Oceanic and Atmospheric Agency on 11 May 2019.
The increasing proportion of carbon dioxide in the atmosphere is important because of its heat absorbing properties. The land and seas on the planet absorb and emit heat and that heat is trapped in carbon dioxide molecules. The NOAA likens CO2 to leaving bricks in a fireplace, that still emit heat after a fire goes out.
Oceans have been such comfortable homes to approximately 2.2 million species since hundreds of thousands of years. Thanks to overfishing, warming, pollution, plastics and other human pressures, now they are turning inhospitable. Apart from all these, there is another major threat to the marine life called the ‘ocean acidification’. It refers to the decreasing pH of ocean water due to the conversion of absorbed CO2 into carbonic acid.
The first victims of ocean acidification are the marine calcifying organisms with shells. Coral reefs, which cradle almost a quarter of marine biodiversity, are also severely affected by acidification. These reefs are formed by the accumulation of calcium carbonate skeletons secreted by the colonies of corals over time over which algae and protozoans grow, imparting beautiful colours to the coral reefs. Due to increased acidification and other reasons, these symbiotic organisms are expelled by the corals, revealing their white calcium carbonate skeleton underneath.