Global Problems: CO2 and the Climate
Carbon dioxide (CO2), water (H2O) and sunlight are the main ingredients used by plants and many bacteria to make the organic compounds they need to survive and prosper (in the process called photosynthesis). Carbon dioxide (CO2) is thus essential to life on Earth. But in excessive amounts it may lead to the undue warming of the atmosphere, the infamous “global warming.”
CO2 has been increasing at a rate that seems alarming: 25% since the industrial revolution and 10% since 1957. Many scientists attribute most of this increase to human action.
According to several climate models, at this rate the CO2 will double sometime in this century, raising the average global temperature anywhere from 1 to 5 degrees Celsius. That higher temperature may transform the Earth in undesirable ways. For example, the polar caps might melt, slowly raising ocean levels and flooding out of existence New York, Hong Kong, Rio de Janeiro and many of the other great coastal cities of the world. The loss of land would destroy the livelihood of a billion people, while the new climate may turn the great agricultural areas of the American and Canadian Midwest into deserts.
Some react to this problem of “global warming” by advocating an end to the practices that increase the CO2 in the atmosphere. But that solution is far from easy, for we create CO2 every time we burn fossil fuels – that is, every time we operate a factory, fly a plane, drive an automobile, or run a tractor. Modern society runs largely on the burning of fossil fuels and changing this habit will require much sacrifice and thus encounter great resistance. Not surprisingly, dissenters demand to know just how bad the problem really is and what alternative solutions exist.
The problem does seem to be catastrophic if one listens to the judgment of the majority of professional climatologists. Until recently they based their pessimistic conclusions on three main factors: the theory of the green-house effect, the fact that the temperature has risen by one degree Celsius in the last hundred years, and the projections they derive from computer models of the climate. Let us take a brief look at each in turn, and then let us look again at the ensuing controversy in the context of the long-term future.
The theory of the greenhouse effect seems about as solid as we could wish. Sunlight is absorbed by the Earth’s surface and re-radiated in the infrared. CO2 does trap infrared radiation, as do other “greenhouse” gases, such as methane (CH4), nitrous oxide (N2O), and ordinary water vapor. And when you trap energy in the atmosphere you make it warmer. Indeed, there is little question that the Earth does experience a very large greenhouse effect. The average air temperature on the surface of the Earth is 14°C (57°F), which is about 32°C higher than the radiant temperature of the Earth (what the Earth radiates). This means 32°C more than can be accounted by the combination of sunlight and internal heat. So we can see not only that the greenhouse effect exists on a large scale, but also that it is a good thing, otherwise the mean temperature of the Earth would be well below freezing.
CO2 is an important factor in this greenhouse effect, even though its percentage in the atmosphere is just 0.035 – its increase coincides with the rise of temperature in the last century. Until recently, however, dissenters have questioned this worry on two fronts. The first is whether there is a connection between the increase in CO2 and the rise in temperature, for most of the increase in temperature took place up to the 1940s, even though in the last twenty years CO2 has increased almost half as much as in the previous 200. Moreover, dissenters dispute even the modest increase in world temperature in the last twenty years on the basis of satellite readings of lower atmospheric temperature (up to a height of seven kilometers). These readings actually show a slight decrease. According to the dissenters, satellite data of the lower atmosphere should be considered far more reliable than inferences drawn from a collection of readings from highly localized weather stations around the world, especially those from cities, where concrete and pollution create “islands of heat.”
In their second front, dissenters argue that changes in temperature result from natural fluctuations in the climate. Ninety million years ago a cold-blooded crocodile, Champosaur, lived only 600 miles from the North Pole. The climate in the Arctic then was like Florida’s today. It is also well known that many hundred years ago England used to enjoy wine from its own vineyards, for the whole of Europe was much warmer then. About the same time the Americas were suffering from devastating droughts. That warm climate gave way to the Little Ice Age, about 400 years ago. But now the Earth seems to be returning to the balmy days of English wine, a time long before the industrial revolution and its massive use of fossil fuels.
In the last few years, the pessimists have challenged the interpretation of the satellite data, largely to their own satisfaction, although the dissenters remain unconvinced. “A stubborn argument against global warming may be discredited by a reanalysis of the data central to its claims,” announces a Science commentary on a crucial report. But the authors of the report themselves point out that the relevant models cannot be used “to determine which of the two satellite data sets is closer to reality.” The pessimists then announce that their “newest global-warming forecast is backed by data from myriad satellites, weather balloons, ships at sea, and weather stations…” as well as by ice-core, animal and plant studies. But, according to S.F. Singer, former director of the U.S. Weather Satellite Service, a report from the National Research Council “confirms that the atmosphere has not warmed appreciably for the past 20-odd years.” (See Figure 4.1) Singer does acknowledge that we are in a period of warming, but he claims this is just part of a natural cycle induced by changes in solar radiation. We can see this rough 1470-year cycle, he adds, superimposed on both glaciation and inter-glacial periods of the last 400,000 years, and perhaps of the last million years.
The third basis for the pessimistic conclusions is the use of computer models of the climate. The computer models attempt to simulate the behavior of the climate some years from now by considering how a relatively few factors affect it. Dissenters point out that these models are gross simplifications of the real climate and the myriad of factors that do affect it (which in many cases are themselves not well understood, as we will see below). Pessimists cannot point to significant forecasts of climate change, which is the acid test required by dissenters.
In fairness, though, we must keep in mind that the climatologists are warning us about the probable effects of the accumulation of greenhouse gases over a period of several decades. They also worry that by the time those disastrous effects are large enough to convince the skeptics, it will be too late to reverse the trend and prevent a catastrophe.
Furthermore, their computer models have been tested somewhat successfully by the retrodiction of significant climatic changes in our distant history (a retrodiction is a prediction concerning what we will find out about the past). That is, in some instances when scientists have applied their climate models to determine what should have happened at, say, the time of the dinosaurs, they have gotten some rough agreement with what we believe really happened (given our knowledge of the geological record). But as climatologist Stephen Schneider puts it, this is valuable circumstantial evidence, but it cannot confirm or deny the model’s detailed regional projections.
As of this writing, a bitter controversy rages on between the two sides, complete with name-calling, accusations of biased reporting, and charges of fraud. This controversy, to make matters worse, has been drawn along political lines, with the Left generally taking the side of strict regulation and the Right that of industry. The left tends to say that there are no two sides, but that would be rather unusual in the history of science.
It is not my purpose to settle this political controversy. My intent is rather to examine the matter philosophically and to argue that we face a condition of uncertainty in which we have a duty to act wisely, and that we will not be able to do so unless we make liberal used of space technology in the context of investigating the Earth as a planet. And to do the latter well, as I have already suggested, requires a vigorous exploration of the solar system.
. Schneider, S. H., Laboratory Earth, Basic Books, 1997, p. 66.
. Ibid, p. 50.
. These are, of course, only educated guesses. Melting of icebergs floating in water would not raise the water levels, but melting of glaciers over land, as in Antarctica, would.
 They have that name because they work in the manner of a greenhouse: they let the sunlight through but trap the heat in.
. The two sides agree that there was a substantial increase in global surface temperatures in 1998 (0.58EC above the baseline of the 1961-1990 period). But skeptics blame El Niño and point out that later in the year the atmospheric temperatures decreased to the baseline average. Science News, Vol. 155, January 2, 1999, p. 6. I expect that this debate will continue for years.
. Recently some researches have argued that on the basis of such evidence we cannot prove that the global temperature was higher then.
 J.R. Christy and R.W. Spencer, Science, Vol. 301, 22 August 2003, pp. 1046-1047.
 “The Weather Turns Wild,” U.S. News and World Report, February 5, 2001, p. 47. This article was based on a report from the United Nations’ Intergovernmental Panel on Climate Change. See also Harries, J.E., et al, “Increases in Greenhouse Forcing Inferred from the Outgoing Longwave Radiation Spectra of the Earth in 1970 and 1997,” Nature, Vol. 405, March 15, 2001.
 See his letter to Science, Vol. 301, 1 August 2003, p. 595. The report in question is Reconciling Observations of Global Temperature Change, National Academy Press, 2000. See also Donald Kennedy’s response, Ibid. I must confess that I am very puzzled by those who claim that the last twenty years were the hottest in the last thousand, while at the same time all sides agree that the rise in temperature since 1900 to now is 0.6C and that the rise in temperature from 1900 up to 1979 was also 0.6C.
 S.F. Singer and D.T. Avery (2007). Unstoppable Global Warming: Every 1500 years. Rowman and Littlefield.
. Op. cit., p. 51.
 The battle is often fought through the most prestigious organs of the press, which tend to favor the doomsday scenarios. For example, on March 5, 1999, the Washington Post ran the headline “Shrinkage Detected in Greenland’s Ice.” According to the World Climate Report, the “real” story is that even though Greenland’s southern glaciers are receding, that recession is more than compensated for by a thickening of the ice sheet in West Greenland, the largest ice mass in the Northern Hemisphere (March 15, 1999). Indeed, satellite data indicate that there had been a cooling trend around Greenland for the previous twenty years.
 According to Singer, the claim that scientists had found a “human fingerprint” in the current warming was inserted into the executive summary of the United Nations’ Intergovernmental Panel on Climate Change (IPCC) “for political, not scientific reasons. Then the ‘science volume’ was edited to take out five different statements – all of which had been approved by the panel’s scientific consultants – specifically saying no such ‘human fingerprint’ had been found.” The editor, a U.S. government employee, later admitted his “indefensible action,” claiming he had been under pressure from higher U.S. government officials. Singer and Avery, op. cit., p. 10. Singer’s source is Frederick Seitz, former president of the National Academy of Sciences, in “A Major Deception on Global Warming,” Wall Street Journal, 12 June 1996, editorial page. Also, S.F. Singer, Climate Policy from Rio to Kyoto: A Political Issue for 2000 and Beyond (Palo Alto, CA: Hoover Institution, Stanford University, 2000), p. 19.