Scarier than temperature rise

Humans as a geological force
[Via CEJournal]


ocean-acidification

Much of the carbon dioxide we spew into the atmosphere dissolves in the oceans, where it causes the water to become increasingly acidic and therefore corrosive to the materials that form coral reefs. In the images above (based on observations and computer simulations), warmer colors indicate less corrosive conditions, whereas cooler colors show increasingly corrosive conditions. Ocean water in the 1700’s (left) was much less corrosive than what is projected for the year 2100. This is one way that we humans have been leaving a geological mark. (Source: NOAA Science on a Sphere)

Today another inquiry has cleared the scientists of the U.K.’s Climatic Research Unit of scientific malpractice in the episode that came to be called “Climategate.” It will no doubt consume bloggers climate activists of all stripes for days to come.

On the same day, a much more important report was published about humankind’s overall impact on the planet. But it will receive almost no coverage.

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Carbon dioxide dissolved in ocean water makes it more acidic. Since the oceans are a major sink for the carbon dioxide we release, we are responsible for the acidic changes in the seas.

Most ocean life that creates a calcareous shell – things like coral, gastropods, and, most importantly, plankton – requires water that is slightly basic to be able to create their shells from the dissolved calcium in the water. Make the water more acidic and they can not make their shells.

If the plankton populations fail, then the entire ocean ecology fails. In the Permian-Triassic extinction event, the greatest extinction of life seen in the Earth’s history, Life in the ocean that produced calcareous structures suffered extinction rates greater than 90%. Close species that did not rely on these calcium carbonate structures saw much lower extinction rates. This is the only extinction event that reduced the numbers of insects.

And all the evidence supports that large amounts of carbon dioxide dissolved in the water was a possible cause. There was a rapid increase in the amount of C12 compared to C13, just like we are seeing today. Breakdown of methane hydrates, something we are seeing occur right now, could have provided the large amounts of C12 seen.

It took 4-6 million years after the event for the world’s ecologies to even begin to recover.

Because the scary thing is in this paragraph, which will probably not be carried very far:

The impact is profound. Carl Zimmer’s reporting for Yale Environment 360 earlier this year, sums it up nicely (and grimly), including this perspective from Andy Ridgwell, an earth scientist at the University of Bristol:

The acidification of the ocean today is bigger and faster than anything geologists can find in the fossil record over the past 65 million years. Indeed, its speed and strength — Ridgwell estimates that current ocean acidification is taking place at ten times the rate that preceded the mass extinction 55 million years ago — may spell doom for many marine species, particularly ones that live in the deep ocean.

“This is an almost unprecedented geological event,” says Ridgwell.