~ The amount of carbon in the atmosphere is increasing and the ocean is becoming more acidic. It may be an "experiment" that the Earth has run before, but it's not the same this time.
The world’s oceans may be turning acidic faster today from human carbon emissions than they did during four major extinctions in the last 300 million years, when natural pulses of carbon sent global temperatures soaring, says a new study in Science. The study is the first of its kind to survey the geologic record for evidence of ocean acidification over this vast time period.
The Science study highlights the rate of change:
Researchers compared the current rates of ocean change to other major acidification events going back 300 million years, and what they found is shocking: never in that long period did the ocean pH fall as rapidly as it is falling right now (lower pH means higher acidity). Ocean pH has already dropped 0.1 units to 8.1 -- it is a logarithmic scale, meaning the drop represents about a 30 percent change in acidity. Within another hundred years, it could drop to 7.8.Those denying that climate change is real and is caused by human activity cannot readily explain why it is so remarkably and precipitously different this time.
At this level, coral, mollusks, and many other creatures will be unlikely to survive. Increased CO2 entering the oceans depletes the carbonate ions that these animals need to make their shells and reefs.