Oceanic carbon dioxide flux. Image credit: NOAA, "The oceanic sink for carbon dioxide:" Sabine and Feely, Pacific Marine Environmental Laboratory, NOAA, Seattle, Washington.
I try to keep my posting on the sunny side of life. Climate change, as fearful as it seems at times, is still a distant risk and one that it is definitely not too late to mitigate. That's the good news. The bad news is that the world's oceans have variously absorbed more than one-third of the last 150 years worth - roughly 130 billion tonnes of CO2 emissions - becoming, as IPS points out, "30 percent more acidic as the extra CO2 combines with carbonate ions in seawater, forming carbonic acid".
Ocean acidification: Still off the radar
The issue of ocean acidification is only barely recognized by government, as pointed out in the IPS story Deep CO2 Cuts May Be Last Hope for Acid Oceans. This ocean acidifying "=Carbon Bomb," which is what Russ George calls the wide ranging estimates of 100 to 500 giga-tons of historic emissions, is acid in the face of marine life, regardless of what we do to reduce on-going carbon emissions.
Uniformly-mixed bathtub metaphor does not apply.
The movement of C02 in and out of the oceans, what scientists call "flux," is not at all uniform from place to place (as pictured above). Similarly, pH or acidity also is highly variable on the ocean surface, as pictured below.
Image credit:Pacific Science Association, PSA Task Force on Ocean Acidification
Ocean acidification, driven by the influx of atmospheric carbon dioxide already placed there during the last century, will proceed for many decades, even if we were able to return, instantly, to an early 20th century C02 emission scenario. The carbon bomb has already been atmospherically detonated, in other words.
How can we shield the ocean from carbon bomb impacts?
There are several earth-friendly choices available to cope with the carbon bomb: the best ones involve scrubbing CO2 from the atmosphere with enhanced biological processes, while emission reductions are separately accomplished (as planned for in Copenhagen, this fall). Examples of ways to increase terrestrial plant fixation of carbon are tree planting, bio-char burying, and grassland restoration. Alternatively, experiments are underway to test the effectiveness of fertilizing the sea with trace iron levels, sufficient to restore marine plankton blooms to historically common levels of productivity.
Cost-effectiveness of ecosystem-coupled methods are far better understood than the proposals we read about for physio-chemical atmospheric C02 scrubbing or sulfur bombing: totally untested ideas from chemical engineers,sulfur-spewing rocketeers, and artillerymen - the "geo-engineers."
Update: Filling the upper atmosphere with sulfur oxides delivered, volcano-like, with artillery shells or rockets, to shield the earth from the sun's heat, will create acid rain, further acidifying the ocean. Think about it.
The mitigation paradox.
The above-listed ocean acidification reduction techniques, if deployed at a large scale, would obviously benefit the climate as well.
However, emission reductions designed solely to prevent a future worsening of climate risk may not necessarily reduce ocean acidification in time to save marine ecosystems. This paradox will be hard for governments and treaty negotiators to grasp. But grasp it they must.
The solution is not "rocket science." Both paths can be followed in parallel: one to reduce emissions and another to defuse the carbon bomb that has already been detonated. No trade-offs allowed, hopefully.
Ocean acidification does not yet have an "Al Gore" to the make the science and the risk of inaction clear to the average person.
Please share your good ideas with us. How best to make it understood?
As an aside, I expect to be challenged, corrected, perhaps even vilified by some, for this post. I say this because the "carbon bomb" concept is new, because the 'gigaton" numbers are imprecise and will remain so, and because the scientific consensus on acidification impacts - among marine biologists mainly - is loose and not often reported outside of scientific journals.
All I ask is that we keep it polite and that you reference whatever interesting sources you can find.
More on ocean acidification.
The Ocean Acidification, Non-Coolaid Test: Will Climate Treaty Delegates Pass?
Ocean Acidification: 100 Years in the Future
Increasing Ocean Acidification Eroding Coral Reefs
Ozone Depletion Contributes to Ocean Acidification in the Southern Ocean
Ocean Acidification Conference: Acidity Up 30% Since Industrial Revolution - Producing Toxic Assets For The World