Q: Will Ocean Acidity extinct calciferous ocean organisms? A: No it can't and won't

Over the previous 1 billion years, earths oceans have steadily become more alkaline - not "more acidic". [ alkalinity is the opposite of acidity ] Oceans were far more "acidic" hundreds of millions of years ago when many of these CaCO₃-shelled creatures (calciferous organisms) were evolving. According to the people who invented this acidification scare these calciferous creatures could never have evolved - because the oceans back then were far too acidic for them to exist!

CO₂ was once plentiful on earth. Where is it go?

pH of oceans can vary from 8.2 to 7.4 depending on time of year, and latitude. Normal range is 8.2 to 7.9. So a few measurements, carefully cherry-picked to show a statistical increase will basically be statistical fraud. Yet most of the time, there's no attempt to even bother doing that. They simply declare ocean acidification as fait accompli. Because no will dare call them out. They rely on intellectual terrorism - baiting people as climate skeptics - as the did with Ian Plimer - See: "Heaven and Earth". I mention Ian because he's one of the few skeptics to cover the acidification scare - in that book. Unfortunately he doesn't cover it very well. He should've put more charts and tables in his book and fewer citations!

Most of the carbon - in the carbon cycle - is present as limestone. This carbon was once in the ocean. It has been sequestered away over hundreds of millions of years; often as calciferous creatures die, and fall to the ocean bottom.

Q: Where did the carbon go?

A: It became limestone.

Over hundreds of millions of years, calcium carbonate as been deposited from oceans to make limestone.

Earth's crust is now about 0.25% limestone. Earth's crust mass ~ 2.77 * 10^22 kg. Leaving limestone = 6.925e+19 kg = 6.925e+07 Gt = 69,250,000 gigatonnes. Let's compare the limestone to the amount of other carbon in the carbon cycle. Assume 13% of the limestone is carbon.

Carbon on earth's crust is:

9,003,000 Gt	Limestone
38,000 Gt	in oceans
5,000 Gt	all fossil fuel reserves on earth

So I calculate there's > 2 orders of magnitude (200 ×) more carbon in limestone, than everywhere else on earth's crust.

So the reason why there's little calcium carbonate available to make carboniferous microorganisms might be because it's nearly all been seqestered away as limestone!! Nowt to do with supposed "acidification".

Global carbon cycle

This diagram, above, has no limestone in it because once CO₂ becomes limestone it's no longer available on earth. This is called Sequestration. In fact, we're now living close to a CO₂ famine. Plants need at least 150ppm CO₂ in the atmosphere to even grow. If the CO₂ levels fall much lower the viability of plant life on earth will be at risk. As animals eat plants - the viability of all life on earth may be at risk with too little CO₂