Not defending or refuting this, really, but thought I'd point to a compelling argument I saw on TED by a "climate engineer." The summary is that he claims if things continue and there are problems and we haven't done anything about them, people like him will step up and say stuff like "we can set off a few volcanoes, put some ash in the air and cool things down." And he thinks you're better off working on the problem now so that people like him don't get to try things which could have unintended consequences. Or at the very least, be a band-aid without neosporin.
Climate engineering is a very interesting idea, but since we don't understand the climate very well, I would start with small steps and leave setting off volcanoes or dumping iron into the seas for a future moment.
We have one planet to experiment with and we will have to live in it for the foreseeable future. Until that changes, I will favor lower-energy experiments.
And, BTW, the whole idea of reducing carbon footprint, building more efficient cities, transportation and generally living consuming less resources is a great idea in itself. Remember, by the next 100 years, we will have a whole lot more people hanging around.
> ...but since we don't understand the climate very well
But, wait. Apparently we DO understand the climate well enough to know that global warming is happening because of the small percentage of CO2 emissions caused by humans, and that by cutting our emissions, we can stop the warming.
Based on that, we must have an extremely thorough understanding of our climate, and it should be trivial to simulate a vulcano going off and see if it cools the climate.
You don't need to understand much of what goes under the hood of your car to draw simple conclusions like "exerting pressure on the brakes slows it down".
You do need considerable understanding of how cars work if what you want is to interfere with the engine functions to, say, increase its mileage.
We do understand enough to point to CO2 emissions as the probable cause of global warming (the less heat we radiate back to space, the warmer we get - it's that simple) but to manipulate the climate to a given objective while avoiding uncontrollable side effects would require a much better understanding of how the climate really works.
As Mark Twain cleverly said, it's not what you don't know that kills you. It's what you are absolutely sure that just isn't that way. Would you take that gamble?
It was an interesting talk.
http://www.ted.com/index.php/talks/david_keith_s_surprising_...