Cleaning up after ourselves

"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".

The greatest challenge

"The greatest challenge of man's future is to provide the energy needed to lift the world's population out of poverty without imposing a cost on the planet that neither humans nor the rest of its inhabitants can bear. The answer to the challenge is in part political and in part technological, but none of the possible technologies are ready. Over the next twenty years, say, we need a massive research program to get them ready - we need to be investing heavily in research into solar energy as well as carbon capture."

Wallace Broecker and Robert Kunzig, "CO2 - Fixing Climate", chapter "Fixing climate".

The biggest problem

"The biggest problem confronting the world, Lackner was deciding at that time, is not whether quarks could exist in a free, unconfined state outside the atomic nucleus - the question that had exercised his brain as a theoretical physicist, and that he pursues these days as a hobby, the way other men might go bowling. The biggest problem was environmental. Malthus and his followers were right: we are headed for a brick wall. But the wall our growing population would soon crash into was not, as the Malthusians thought, the limited resources of the planet. It was the limited ability of the planet's thin biosphere to sustain the environmental impact our growing population and spreading industry are inflicting on it.
Ultimately that problem came down to energy. "If we had cheap, clean, and copious energy, we could solve our problems about being sustainable," Lackner says. Unlike other energy sources, fossil fuels are cheap and copious right now. If we could just make them clean, they would be perfect."

Wallace Broecker and Robert Kunzig, "CO2 - Fixing Climate", chapter "Scrubbing the air".

As the title of this chapter suggests, Klaus Lackner thinks there is a solution: capturing CO2 out of the ambient air, and storing it as carbonates, the way nature does it with the weathering process, albeit at much too slow a rate to keep up with our emissions. As crazy as it may sound, some people have thought about it seriously, and are beginning to show it could be feasible. I'll make another post about it later, but I just would like to add here an excerpt from Lackner's 2003 Science paper ("A guide to CO2 sequestration"):
"CO2 is three times as heavy as fuel and therefore cannot be stored in cars or airplanes. CO2 from these sources will have to be released into the atmosphere and recaptured later. Currently, photosynthesis is the only practical form of air capture. Capture from air flowing over chemical sorbents - such as strong alkali solutions or activated carbon substrates - appears feasible but needs to be demonstrated. [...]
Because the atmosphere mixes rapidly, extraction at any site, however remote, could compensate for emissions from anywhere else. By decoupling power generation from sequestration, air capture would allow the existing fossil fuel-based energy infrastructure to live out its useful life; it would open remote disposal sites and even allow for the eventual reduction of atmospheric CO2 concentration."

Is nuclear the energy solution?

A rational critic of nuclear energy as a practical solution to our energy and global warming problem:

"It's a measure of how urgent the CO2 problem has become that some antinuclear environmentalists have lately been willing to reconsider their long-standing opposition. Nuclear power, as its proponents frequently remind us, has killed far fewer people than coal mining, not to mention pollution from coal-fired power plants. But that doesn't mean there aren't rational reasons to be skeptical of it. There is still no permanent disposal site anywhere on Earth for waste that will remain dangerously radioactive for thousands of years. And the fear that a proliferation of civilian power plants could promote the proliferation of nuclear weapons has only grown more acute since September 11, 2001. The huge expansion of nuclear power that would be necessary for it to contribute significantly to resolving the CO2 problem is, in our opinion, just not going to happen."

Wallace Broecker and Robert Kunzig, "CO2 - Fixing Climate", chapter "Green is not enough".