Friday, June 5, 2009

Global Warming I — Is Global Warming a hoax?*

Wallace S. Broecker wrote an article in a 1975 issue of the Science magazine in which he asserted that "We may be in for a climatic surprise." That sentence has instigated a maelstrom of scientific activity related to what we now know as global warming.

Critics have frequently commented that environmentalists are more concerned about the snail darter than human beings, but global warming is not simply an effort to preserve ecological balance. True, the polar bear is endangered, but human habitats are also directly at risk. Our grandchildren may witness an abrupt rise in the sea level that will submerge coastal areas and turn lowlands into swamps. Desert areas would expand dramatically, further reducing the livable areas in the world. The Arctic and Antarctic regions would melt and become more moderate climates causing adverse effects on the ecological system. The destruction of major habitats for humans may well result in gigantic economic catastrophes as well as land wars among millions of people displaced by the revamped earth. To help understand how people can fight over living space consider the ferocity of hostilities generated the last sixty years over a relatively small geographic area in Israel-Palestine. It is not a happy prospect.

We cannot afford to underestimate the threat. Nevertheless skeptics are alive and well. Politicians and various special interests believe that the cost of reducing carbon emissions is not justified by the evidence produced by the scientific community. The question is whether global warming is like the swine flu where the alarmists anticipated an epidemic that never came or more like the levees of New Orleans where the warnings were oft repeated, but nobody listened.

It appears to me that in order to disbelieve Broecker’s science, you must successfully challenge at least one of three premises. They are as follows:

1. Carbon dioxide and other gases collectively known as the greenhouse gases preserve heat in our atmosphere. The first proposition has been an accepted fact since the nineteenth century. Without these gases, heat from the sun would bounce off the earth, and we would freeze like other planets. On the other hand excessive carbon dioxide in the atmosphere will overheat the earth. I understand that even the severest critics do not contest the existence of the greenhouse effect.

2. Over the last century, industrialization has been accompanied by carbon emissions of unprecedented amounts. This second premise is based on a plethora of scientific measuring that has been thoroughly documented for at least fifty years. Fossil fuels are far and away the principal contributor to this increase. I am not aware of much dissent on that issue either.

3. If the greenhouse emissions continue to grow, the livability of the planet will be materilly affected at some time in the future. This third proposition is the bone of contention. Are gases being emitted of sufficient quantity to cause a material alteration of climate?

The mean temperature on the earth has been rising over the last century. The year 2005 is reported to be the hottest year on record. Glaciers are melting, and rain forests are receding. The dissenters contend that the rise is fully explainable by the natural rhythms which occur in nature. They deny that fossil fuel deposits are a significant factor. It is noteworthy that the critics have not been very successful in convincing their peers. The Intergovernmental Panel on Climate Change (IPCC), which is the most influential worldwide body in climatology, concluded that greenhouse gases are responsible for most of the rise in temperatures in recent decades. That conclusion has been endorsed by 40 scientific societies and academies of science, including all of the national academies of science of the major industrialized countries.

I do not claim to have any expertise on a subject so complex and futuristic as global warming. Nevertheless, I have more confidence in the scientists of academia than those employed by political lobbies to come up with a specified result. Scientists, good scientists, are loyal to the advancement of knowledge regardless of the consequences. When Galileo declared that the earth revolved around the sun, he was merely reporting his findings. The church that forced him to recant had a fixed view on the universe and expected science to affirm its own dogmatic vision.

It would be unfair to characterize any one who disagrees with the scientists as seeking to alter the truth. Nevertheless, the case for an impending global catastrophe seems to represent the work product of the best minds in the world who have dedicated their professional lives to the study of our environment.. Moreover, the skeptics are up against Pascal’s wager. If the skeptics should persuade us that global warming is a hoax and they are wrong, the consequences would be horrendous. On the other hand the risk of error by the scientific establishment is not so great. Admittedly the collective cost of a wild goose chase would be significant, but the reduction of carbon dioxide would still produce a more pleasant, healthier climate. On balance, I consider it risky for our society to ignore the warnings of a coming global warming surprise.

[I have relied on Broecker and Kunzig Fixing the Climate (Hill and Wang 2008) and the article on global warming in Wikipedia for most of the material of a technical nature. Both are provocative, informative and excellent reading for a mainline novice such as me.]

* This posting is the first of three installments discussing global warming.

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