This has been a growing concern. The rapid increases in the CO2 levels -- blasting past 400ppm as we speak -- that has several scary consequences.
First, there's the greenhouse gas (GHG) thing and the rising temperatures of the air and land.
Second, the excess CO2, at least some of it, is absorbed into the oceans. This increases the acidity of the oceans. Higher acid levels could wipe out shell fish, coral reefs and other things/animals that are critical for the health of the oceans (and of the planet).
Here's what the article and the scientists said:
Hans Poertner, professor of marine biology at the Alfred Wegener Institute in Germany, and co-author of a new study of the phenomenon, told the Guardian: "The current rate of change is likely to be more than 10 times faster than it has been in any of the evolutionary crises in the earth's history."Ouch!
Seawater is naturally slightly alkaline, but as oceans absorb CO2 from the air, their pH level falls gradually. Under the rapid escalation of greenhouse gas emissions, ocean acidification is gathering pace and many forms of marine life – especially species that build calcium-based shells – are under threat.