Saturday, July 11, 2009

Global Warming III - What is the solution?

Even if we have the political will to address the global warming threat, what can we do about it?

Carbon emissions increased globally from a rate from about 1.1% per year in the nineties to more than 3% a year in 2001-2004. Broecker and Kunzig comment, "[N]o matter what happens in the West, the world’s energy consumption is going to increase dramatically in this century, not decrease. And most of that energy will probably continue to come from fossil fuels, above all coal. They are cheap, readily available, and incredibly convenient to use - and we have a global infrastructure of power plants and refineries and pipelines and gas stations that is built around using them." (P.189)

The environmental lobby has understandably focused on conservation measures that cut down on the volume of emissions. The list of energy saving ideas is long and growing. Each proposal has its champions- higher gas mileage, electric and hydrogen powered cars, windmills, solar systems, nuclear power, ethanol and so on. All of these proposals appear to be more of a palliative than a solution. For instance, it would require a sixty five foot wind mill for every man woman and child to meet our needs. Nuclear power is promising, but until nuclear fusion or some other safe, reliable system of waste disposal is developed, it will continue to be limited. Solar power is a long way from becoming cost efficient. It now costs about twenty times as much as coal fired energy. And then there is ethanol. The best I can tell, the chief function of ethanol is to help politicians win votes in the Iowa caucus.

A second approach would be to remove carbon emissions before they reach the atmosphere. The power industry is enthusiastic about flue-gas scrubbing that removes carbon from the emissions before they are released into the air. Scrubbing can be effective on new plants under construction but there is no economical way to add scrubbers to existing power plants. Scrubbing is not practical for automobile emissions, which represent 20% of the carbon emissions. Scrubbing may never become a universal solution to carbon dioxide removal. Nevertheless, coal is the cheapest and most plentiful energy source, and technology that can make the product environmentally friendly should be a welcome addition to the arsenal.

Still another approach involves preserving the capacity of nature to remove carbon from the atmosphere. Much is made of the reduction of rain forests in places such as South America. A green world will be cleaner than not, but land sources for absorbing carbon dioxide such a rain forests tend to be overestimated as the means of containing the spewing of carbon into the air. Only about 15% of the carbon dioxide emissions are consumed by natural forces on land, less that half as much as is absorbed in the ocean. That leaves 50% to remain in the atmosphere. I suspect that the best means of retaining nature’s capacity to absorb carbon may be to avoid heating up the earth, because warm waters actually release carbon dioxide into the air. So we are in a Catch 22. The earth warms and the earth consumes less carbon. The carbon retained in the atmosphere heats up the earth in turn releasing more carbon. And so on.

There remains one more option, namely the removal of carbon dioxide from the atmosphere. This alternative was once considered the most ineffective solution because carbon is far less concentrated in the atmosphere than at the source of emissions. Flue gas is reduced from approximately one part in ten to one part in a million when it reaches the atmosphere. As a result, the scientific community long ignored that alternative.

Claus Lackner, a theoretical scientist, came to the conclusion that there is existing technology available that could remove carbon from the atmosphere efficiently and economically. He sold Walter Broecker on the idea, and Broecker became his champion. Through the use of venture capital, Lackner teamed up with Allen Wright to form a company that built an air extraction prototype. The prototype has been completed and Lackner’s company has declared the project a success.

If it works, the air extraction project solves many of the seemingly intractable issues. The new technology takes only a fraction of the space of wind power and does not raise the esthetic and environmental issues that wind power presents. A carbon waste must be disposed, but it can be done without presenting the toxic threat of nuclear waste. Also, because the carbon is found everywhere, the scrubbers can be located conveniently in the parts of the world where disposal is undertaken. Most important, this technology may prove to be affordable.

Broecker believes that the Lackner project holds the best prospect for fixing the climate. I certainly hope that he is right. Under any circumstances, I am convinced the ultimate solution, if there is one, will come out of our capacity to invent new technologies and that the best investment of public and private resources lies in research and development projects such as the Lackner company.
Broecker and Kunzig Fixing the Climate (Hill and Wang 2008)
"Scrubbing the Skies," (March, 5, 2009)

No comments: