Acid baths

There have been a lot of articles similar to this one.

Acid sea will dissolve coral reefs

CORAL reefs, lobsters and other marine creatures that build calcified shells around themselves could soon dissolve as climate change turns the oceans increasingly acidic.

The carbon dioxide spewed into the atmosphere by factories, cars and power plants is not just raising temperatures. It is also causing what scientists call "ocean acidification" as around 25 per cent of the excess CO2 is absorbed by the seas.

The language is pretty typical. CO2 is "spewed" by human activities. I guess the earth itself doesn't "spew" CO2? Even though all human CO2 emissions together, through industry, agriculture and just plain living, is just a tiny fraction what what the earth itself emits?

Images of dissolving coral reefs and crustacean shells are pretty common, too.

But how true is it? Well, take a look at the photos here.

The shallows near Dobu Island off Papua and New Guinea have active underwater fumaroles pumping out virtually pure CO2. The sea grass is extraordinarily lush and healthy and there is very healthy coral reef a few metres away.

Both photos show bubbles of CO2 which continually flow. I collected samples of gas years ago for a vulcanologist and he reported back to me that it was "virtually pure CO2".

There's also plenty of information from Seafriends, on ocean acidification
Part One
Part Two
Part Three

Meanwhile, on the topic of atmospheric CO2, there's this article from the Financial Post

In praise of CO2

Then, in the 1980s, ecologists realized that satellites could track production, and enlisted NASA to collect the data. For the first time, ecologists did not need to rely on rough estimates or anecdotal evidence of the health of the ecology: They could objectively measure the land's output and soon did -- on a daily basis and down to the last kilometre.

The results surprised Steven Running of the University of Montana and Ramakrishna Nemani of NASA, scientists involved in analyzing the NASA data. They found that over a period of almost two decades, the Earth as a whole became more bountiful by a whopping 6.2%. About 25% of the Earth's vegetated landmass -- almost 110 million square kilometres -- enjoyed significant increases and only 7% showed significant declines. When the satellite data zooms in, it finds that each square metre of land, on average, now produces almost 500 grams of greenery per year.

Why the increase? Their 2004 study, and other more recent ones, point to the warming of the planet and the presence of CO2, a gas indispensable to plant life.

The more I look into the role of CO2, and historical atmospheric amounts of it, the more I become convinced that we have been living in a CO2 deficit. In the 4-5 billions years or so of Earth's history, atmospheric levels of CO2 have been much higher for much longer. I begin to suspect life on Earth would greatly benefit from increased CO2 levels, and that levels of 1000ppm or higher would be desirable.

Those who believe that CO2 is a pollutant and blame humans for increases in the last 100-150 years suggest the the pre-industrial levels of 250ppm were somehow better than today, and there's even a website and organization dedicated to limiting atmospheric CO2 levels to 350ppm. Plant life begins to suffer when levels drop to 200ppm, and die at 150ppm. Past levels have been as high at 4000ppm, possibly more. It's suggested that it would take CO2 levels of at least 5000ppm before they became harmful to humans, but that this is just an educated guess. We really don't know how high the levels would have to become before they are harmful (it's a given that levels high enough to displace oxygen would be harmful, no matter how ordinarily harmless it might be).

Back to the acidification of oceans, coral reefs evolved at a time when atmospheric levels of CO2 - and the acidity of the oceans - where much higher than they are today. If they were able to adapt to less acid oceans to survive today, why would they suddenly not be able to adapt back to the levels they evolved in?