"Fixing climate by taking carbon dioxide back out of the atmosphere is not the same as fixing climate by putting sulfur dioxide in. It is not "geoengineering". It is much more conservative than that. Our problem with carbon dioxide is an unintended consequence of a long series of fantastic inventions - from trains, planes, and automobiles to electric light, television, and computers - that have collectively liberated the citizens of industrialized countries from want and physical labor, lengthened their lives, and enriched them tremendously. Billions of people on Earth, the kind of people who must still carry their water from a distant well or their firewood from a distant copse, remain eager for that kind of liberation. The moral strain, if there is one, lies not in our having achieved what we have by burning fossil fuels; it lies in not taking responsibility for the consequences. That's what capturing CO2 out of the air does - in such a way, unlike SO2 injection, as to minimize the danger of further unintended consequences. It is not a "technical fix" that allows us to burn more fossil fuels, any more than sewage systems allow us to eat more. It is merely cleaning up after ourselves."
Wallace Broecker and Robert Kunzig, "CO2 - Fixing Climate", chapter "Fixing climate".