Avoiding Global Warming

It may not be necessary to make large efforts to avoid global warming. First of all, it may not happen, and, secondly, it may not be harmful if it does. The warming observed to date, which may or may not be partly due to human activity, seems to have been beneficial in lengthening growing seasons in temperate and northern climates. Since serious efforts to reduce CO₂ emissions or to increase CO₂ sinks are likely to be extremely expensive, for the present it is best to wait.

On this point it is necessary to be blunt. The strongest advocates of reducing CO₂ think we use too much energy quite apart from questions of supply and possible side-effects. Therefore, they look for reasons to solve the global warming problem by reducing civilization. Not all think that way, but such ideas are providing a lot of the force behind the campaign, e.g. as proposed in former Vice-President Gore's book, Earth in Balance and his recent movie An inconvenient truth.

The Kyoto agreement involves the developed countries undertaking to reduce their CO₂ emissions to 1990 levels by 2010. (I think I remember it correctly.) The backward countries do not agree to do anything, and China and others will increase their emissions enormously. Fortunately, the US Senate has not ratified the agreement.

Here's a somewhat revealing quotation from early in the "energy crisis".

``We can and should seize upon the energy crisis as a good excuse and great opportunity for making some very fundamental changes that we should be making anyhow for other reasons.'' - Russell Train, Science 184 p. 1050, 7 June 1974.

Train was EPA Administrator at the time, and after that became head of the World Wildlife Fund.

Nevertheless, it still may turn out that CO₂ emissions are giving rise to substantial global warming and that is harmful. I think nothing very costly will be done unless and until actual harm is experienced. In that case, what can be done?

Replace coal, oil and natural gas plants for generating electricity by nuclear plants. Replacing coal burning plants should get the highest priority, because they generate the most CO₂ per unit of energy generated, and because their emissions cause substantial lung damage. (It is interesting that some the proposers of "carbon taxes", both in America and Europe, want to include nuclear energy as a target of the "carbon tax". There is clearly more on the agenda than global warming.)
Solar energy in various forms would also work, but it seems to be very costly in spite of the best efforts of its advocates.
Unfortunately, generating electricity without putting CO₂ into the atmosphere probably wouldn't be enough if the global warming problem is serious. The next step is to use nuclear produced electricity for space heating and other direct uses of heat.
The most difficult step is to use electricity for automotive transportation. In spite of very vigorous research, batteries capable of giving electric cars reasonable range have not been developed, although there seems to be no law of nature making them impossible. Here's a scheme that would ameliorate the problem even if lead-acid batteries had to be used.
Another approach is to use hydrogen generated by splitting water with (say) nuclear electricity. Cars powered by liquid hydrogen have the potential of matching the performance of gasoline powered vehicles. The hydrogen tanks will need three times the internal volume of gasoline tanks and still greater external size because of the insulation required. BMW has demonstrated a liquid hydrogen powered internal combustion engine car. Schemes for using hydrogen in other forms than liquid are unlikely to have the required range. See the page on hydrogen for more details.
Some people seem to believe that using hydrogen gets more energy. It only provides a way of using nuclear or solar energy. Apart from its possible use to reduce global warming, hydrogen it likely to be the solution for personal transportation when petroleum runs short.
Rather than putting all the effort into reducing carbon emissions, it may be more cost-effective to put some effort into removing more CO₂ from the atmosphere. Plants remove CO₂, but only while they are growing. A climax forest may be in equilibrium; apparently the exact facts are not yet known.
What will surely work is to cut down forests, not burn the wood and replant the forests with fast growing trees. When these trees reach a size at which their growth slows, they would be cut again. Back in the carboniferous era, trees fell into swamps which evidently provided a reducing environment. The oxygen and hydrogen in the wood were re-emitted into the atmosphere, and the carbon became coal. This process will work for us too (to reduce CO₂ (it takes too long to make coal) if it proves necessary. Canada and Siberia have large forest areas not being used for other purposes.
Perhaps Brazil might be persuaded that the trees being cut down in the Amazon to make more farmland should not be burned. Persuading them of that is likely to be easier than persuading them to forgo the farmland.
An article Resurgent Forests Can Be Greenhouse Gas Sponges from Science of 1997 July 18 discusses the effect of new forest growth on removing CO₂. It doesn't discuss harvesting the forest repeatedly.

Research is needed
Some have criticized my including the above proposal to repeatedly harvest forests on the grounds that it is not worked out in detail. It would be a major research project to work out any such proposal in enough detail to determine how much it would cost, how much CO₂ would be removed, and what other good and bad effects might occur. For example, one would have to study under what conditions the wood harvested would just oxidize again. This might depend on soil and latitude. How fast the trees would grow depends on latitude and might be enhanced by fertilization. I suspect the studies would cost many millions of dollars and take many years. The problem may be of sufficient magnitude to justify this.
There are also various schemes for getting the ocean to extract more CO₂ from the atmosphere such as iron fertilization. This was proposed, then refuted and then rehabilitated technically by people who were against actually using it. Here's an amusing reference. The researcher, Kenneth Coale, ends up saying "I feel compelled to carry out this research in a way which is environmentally responsible." Presumably, he is one of those, along with Stephen Schneider, who are dubious about any form of "global engineering". An Australian study reported in 1999 confirms that iron fertilization can be expected to have substantial effects in the Southern Ocean.
Here's an article Climate Controls by Gregory Benford, a physicist at UC Irvine and science fiction writer. He describes many possibilities for mitigating global warming. His article is more comprehensive than this one.

Avoiding Global Warming

Research is needed