Geoengineering as it applies to climate change is any man-made effort to artificially change the climate. Rainmaking would be a simple example. A more complex example would be to lower global temperatures by filling the upper atmosphere with sulfur aerosols.
Think of it this way. Aerosols are solid or liquid particles in the atmosphere. Aerosols scatter and absorb radiation and help make clouds. Volcanoes pump lots of aerosols into the air and can have a dramatic short-term cooling effect on the atmosphere. So, the thinking goes, why not just pump our own sulfur aerosols into the stratosphere and lower the earth's temperature that way?
Another idea for geoengineering was put forth by a long-time climate denier named Bjorn Lomborg. His big idea would involve having 1,900 robotic ships wander around the Pacific Ocean churning seawater into the upper atmosphere. This would produce a lot of clouds which would reflect the sun's energy back away from earth.
Whether sincere or cynical, efforts to promote geoengineering have yet to really take off. Other than the fact that spinning up these ideas would take a lot of time and money that could be better spent elsewhere, most observers see at least two objections to these schemes.
Carbon dioxide persists in the atmosphere for a far longer time than sulfur aerosols. So sooner or later the cooling effect of the aerosols will wear off unless you keep pumping sulfur aerosols into the atmosphere. Of course that would have a significant negative affect on air quality, but hey, one problem at a time, right?
The other big objection most folks have is that they attack the symptoms rather than the disease. Global warming is a symptom of a disease in the atmosphere of the planet. The disease is an imbalance of chemicals, mainly an overload of carbon dioxide that has accumulated rapidly over the last couple of hundred years due to the extensive use of fossil fuels.
Geoengineering schemes attack the symptoms without addressing the underlying disease. There are reasons for this. The cynics might easily believe that geoengineering is a diversion put forward by those whose interests would be adversely affected by a real clampdown on carbon emissions.
Other folks seem genuine in their attempts to sell geoengineering schemes because they have essentially given up on our ability to directly attack the greenhouse gas emissions problem in a way that would effectively prevent major climate change. I find this undercurrent of defeat an especially worrisome thing to ponder.
Bottom Line: Geoengineering schemes do nothing in and of themselves to reduce the levels of greenhouse gas emissions such as carbon dioxide. The only way that can happen is the go after the source. And if you don't reduce the greenhouse gases, then all the insidious side affects will continue, mainly ocean acidification.
There is no quick fix to this problem. Mankind created the problem by messing with Mother Nature so what makes us think we can fix the problem by messing even more with Mother Nature?
