What we are trying to do is engineer our way out of the climate change mess as opposed to attempting the politically difficult regulation of greenhouse gas emissions. While decreasing the greenhouse gas source rate is commendable and most likely required, there may be ways to provide anthropogenic sinks of these gases. If successful, the carbon dioxide content of the atmosphere can be held at some steady-state level, because then the anthropogenic carbon dioxide source rate will be balanced by an anthropogenic carbon dioxide sink rate.

These sequestering processes are designed to bury the carbon-containing materials deep in the ground or ocean so the carbon dioxide cannot re-enter the atmosphere easily. Simply growing biomass is inadequate, because you get an initial carbon uptake from the atmosphere, but this ceases after the plants mature (they stop taking up more carbon dioxide than is being released nearby) and when the trees die, the carbon is released back into the atmosphere in the form of carbon dioxide and methane.

Pumping carbon dioxide into the deep ocean can create new environmental problems--how does the life at the bottom of the ocean deal with the pools of liquid carbon dioxide?

In either case, the sheer size of the operation to fully sequester the anthropogenic carbon dioxide is overwhelming for current practices to deal with, since over six BILLION tons of carbon have to be moved per year. We'd probably emit more carbon dioxide while generating the energy required to do these processes than we actually sequester!

Here, we are trying to mitigate the warming effect from the anthropogenic greenhouse gases, instead of trying to remove the gases or prevent their release.

There are environmental problems associated with the global-size nature of trying to alter the planetary albedo. Floating reflective platforms on the oceans may drift out of position and possibly affect ocean surface currents, besides being too large and numerous to build and deploy in any reasonable amount of time. Not enough land could probably be devoted to reflection sites, and the re-direction of sunlight away from the ground will affect the lifeforms inhabiting the land underneath.

Getting enough dust particles in the global atmosphere to increase the planetary albedo by more than a few percent would require more dust than is released by several large volcanic eruptions. Distribution of the dusts and keeping them suspended in the air would be problematic. And that much dust in the air will probably be a pollution problem in itself, unless the dusts were somehow kept in the stratosphere and above (and then, this will probably adversely affect the stratospheric ozone layer).