Real Climate has a good post on geo-engineering and why it is only fitting as a final act of desperation, not a policy platform. It expresses very well all my own misgivings (it's a terribly dangerous one-chance-to-get-it-right experiment on the entire planet, it commits the human race to centuries of climatic meddling, it will ultimately be more expensive and harder to agree on than simply reducing CO2) so I won't enumerate them here, just go read it all there.
But I will emphasize one of the points Ray Pierrehumbert mentions that is too often overlooked.
As anyone who follows the science closely is aware, currently only about half of our emissions of CO2 into the air are remaining there. Much of the rest is going into the waters of the upper ocean. This is what is causing the observed acidification of the ocean and this is its own very serious problem.
This is not a new realization, but recently the Australian Research Council's Coral Reef Studies division issued a press release detailing what the future may hold for the world's coral reefs.
The world's oceans are becoming more acid, with potentially devastating consequences for corals and the marine organisms that build reefs and provide much of the Earth's breathable oxygen.
The acidity is caused by the gradual buildup of carbon dioxide (CO2) in the atmosphere, dissolving into the oceans. Scientists fear it could be lethal for animals with chalky skeletons which make up more than a third of the planet's marine life.
...is how it begins and the take home message is that this already anticipated problem is happening at a much faster rate that had been expected (Sound familiar?).
It is a very sad reality that the decimation of the world's coral reefs may be no more than a couple of decades or less away. I have tried to ask in discussions with economically minded folk just what the dollar value of, say the Great Barrier Reef is. Is it only the tourism revenue? Perhaps that plus some other cascading effects like loss to fisheries can get us a number. But of course my real point is to ask if dollars are indeed the only measure of a coral reefs value.
It is not just corals that are in danger from ocean acidification, the press release also notes:
It isn't just the coral reefs which are affected - a large part of the plankton in the Southern Ocean, the coccolithophorids, are also affected. These drive ocean productivity and are the base of the food web which supports krill, whales, tuna and our fisheries. They also play a vital role in removing carbon dioxide from the atmosphere, which could break down
A break down in the ocean's ability to sequester some of our CO2 would mean that levels would rise even faster than anticipated, another feedback effect, and again it is one we may be seeing happen already, much sooner than expected.
These are huge issues and issues that are sidelined at yet more of our own peril when policy discussions are allowed to focus on geo-engineering "fixes" that do not involve actual removal of CO2 from the atmosphere-ocean carbon cycle (ie sun shades, mirrors, statospheric aerosols).
Just how many ways does an idea have to be wrong before we can permanently leave it in the trash can where it belongs?
My denialist Dad has been pointing me to Tim Ball's argument that the baseline CO2 at 280 ppm is much too low. Were that true, it would mean that much more than half of the industrial emissions of CO2 are still up there, and the system is sensitive to smaller amounts of CO2 than we thought.
Don't you mean that if true that would mean much more than half is being sequestered?
Do you have a reference to Ball making that argument, I don't recall reading that from him before, though it is certainly no surprise!
Thanks for the comment.