Courtesy of Google alerts (yet another reason to be grateful to Google, and I’m wondering when they’re going to ask for my first-born child), I discovered the Gerry’s Elephantine Blog. Loving the name and the writing. Intelligent analysis laced with dark humor: my favorite cocktail.
Gerry recently posted on climate change and ocean acidification. To really give you the flavor, I’m posting an extended quote here. Can’t really do justice to his blog with a summary, would just boil out the humor and the clarity of the prose. (Learn more about Gerry Patterson here.)
"The most dangerous thing about the current global warming event is that it could trigger the release of clathrates. And if that happened, then we would be in serious trouble.
Since the turn of the century it has been confirmed that the pH of the oceans is now decreasing. And as I said this is something that should worry us greatly, because all biological systems are very sensitive to pH. For example our bodies contain their own mechanism for regulating the pH of our blood. If your body’s pH should stray much from 7.4, you will get sick. Very sick! It has been postulated (with good reason) that the pH of the ocean might have been around 7.4 when our mammalian ancestors left the ocean in a previous geological era.
Similarly if the ocean’s pH should change the entire planet would get very sick!
As a land based species we have a terrestrial-centric view of our ecology. However three quarters of the surface of this planet is covered by water. Life began in the oceans and the marine ecology is a major player in the carbon cycle. It is the oceans that are the greatest carbon sink (and by corollary the greatest oxygen source) and paradoxically if they break down could become a major carbon source.
Photosynthesis is carried out by small marine organisms. These either go into the food chain, or sink to the ocean floor, and would be one of the sources for the formation of clathrates, since when they decay they form methane.
It is possible to imagine how the oceans could be the driving force behind an extremely rapid global "change of state".
- Carbon dioxide causes global warming. The jury is in on this. There are still a few (so-called) sceptics. But we need to be sceptical of their motives and associations. Release of fossil carbon skews the balance of the carbon cycle and the greenhouse warming that results leads to ice
packs and glaciers melting.
- Glaciers and marine ice packs reflect sun. And when the melt they expose (darker) areas of the planet that absorb heat much more rapidly. This leads to a "positive feedback loop", causing even more rapid warming and new warmer currents of water. This may be happening now. It is the most
likely explanation for the melting of polar ice, which can be seen from satellite images. It is more rapid than was expected and has caught many observers by surprise.
- As the warming continues, clathrates melt. This leads to massive releases of methane, a highly potent greenhouse gas that leads to a "super greenhouse" event. This becomes a dangerous positive feedback loop, that changes the Earth’s atmosphere and climate dramatically.
- Methane quickly breaks down into carbon dioxide and water. Although carbon dioxide is not so potent a greenhouse gas, the much higher concentration of carbon dioxide lowers the pH of the oceans to such an extent that marine photosynthesis slows.
- The oceans are no longer a carbon sink and are a major carbon source. Almost all marine vertebrates perish due to the deadly combination of low oxygen and low pH.
- Ninety-eight percent of all vertebrates become extinct.
One of the frightening things about the above outline is that it could happen very quickly. One year us terrestial mammals are frolicking in our recent interglacial state, which we all know and love. Then there is sudden switch and we are in the new clathrate melting state, which we should all fear greatly. Furthermore once the change of state occurs it is almost impossible to change it back. Eventually micro-organisms will adapt to the new environment and transform the atmosphere back to another cozy interglacial state but that may be half a million years in the future. A future that our species may not be around to participate in. . . .
All of this may sound "alarmist". That’s because it is very alarming! The scenario outlined above would be a Catastrophe with a capital "C". However the most frightening thing about it is that it might have actually happened about 250 million years ago, at the so called PT boundary event, otherwise known as the Great Permian Extinction. As you might expect with a name like Great Permian Extinction it was a rather lethal event. It was possibly the most significant mass extinction event in our geological history and it could have run the same course as outlined in the above nightmarish synopsis. There is a considerable body of evidence building that this event began with the release of fossil carbon which lead to the subsequent melting of clathrates and ended in the greatest mass extinction of all time."