Pascal's Wager and Global Warming

Ben Ewen-Campen

Since measurements began in 1958 -- and it can be assumed to have been the case since the industrial revolution -- emission of carbon dioxide into the atmosphere has risen steadily as a result of the burning of fossil fuels (Quay, pp 2344). Although there is much argument over the implications of increasing carbon dioxide levels in the atmosphere, there are several points that almost all scientists would agree on: firstly, carbon dioxide acts to absorb radiated heat; if present in our atmosphere will do just that to some extent. Second, the concentration of carbon dioxide in our atmosphere is rising. Third, the temperature of the planet is rising - although the amount of this increase and the causes of this rise are subject to disagreement (Philander, pp 193).

When I was at school in Vermont, one of my teachers explained to me Pascal's Wager. According to this teacher, the philosopher and mathematician Pascal had tried to establish the costs and benefits of believing in God. He saw it in this way: you can either believe in God or not. If you do believe in God, and there is in fact no God, then you will perhaps have spent some extra energy unnecessarily abstaining from certain pleasures and wasting your Sunday mornings in Church, but overall you did not give up too much. And, it could be argued, you may have actually treated your fellow men more kindly then you would have otherwise. If, however, there is a God, and you believed in him, then you get eternal salvation.

On the other hand, you could choose not to believe in God. If there is no God, then you are fine. You can sin all you like, you can allow yourself transgressions and forbidden acts, and the only punishments you will face will be those of this life. If, however, you lived thusly and there is a God, then you face an eternity of torture and unbearable misery. So, Pascal reasoned, one would do best to believe in God and act accordingly. That way, if you're wrong, the worst thing that could happen is that you were more pious and caring then you may have otherwise been. If you do not believe in God and you turn out to be wrong, the risks become terrifying.

My teacher suggested that I apply this same logic to global warming. It is a matter of playing the odds. There is certainly evidence that the current rise in temperature is in fact being caused by the same environmental processes that have caused all the other major climate changes in our ecological history - of which there have been many - and has nothing to do with our industrial practices. Those who believe that global warming is not truly a problem also cite the difficulty of accurately obtaining a global temperature. And, if we were able to obtain an accurate global temperature today using satellites and undersea sound measurements, we would have no data from the past with which to compare! In addition, some scientists believe that no matter how much carbon dioxide we pump into the atmosphere, the earth will always be capable of removing that carbon dioxide through photosynthesis by algae and land-plants. (These ideas were all mentioned in class discussion on March 25, 2003.)

These are all valid arguments, and I certainly do not have any authority to agree or disagree with them. However, it seems clear to me that the possible outcomes of global warming are simply too catastrophic to risk. What are some of these possible threats? Scientists have hypothesized that global warming could melt ice caps, which would raise sea levels and destroy coast line. In addition, the melting of ice caps would drastically alter the salinity of the surface-water, which plays an important role in the global ocean-circulation. This could severely impact heat-transfer over the globe (the warm water traveling from the equator to the poles is one of the major components of temperature circulation on the planet), and could cause storms and floods, and droughts.

If temperature zones substantially shifted, the ecosystems that have evolved in a given location will face unknown challenges. Food chains could be altered or destroyed, reproductive cycles could be threatened, new diseases may be capable of reaching zones that were previously too cold or too warm. There is evidence that the recent temperature increase in the ocean has already been responsible for the destruction of much coral. (This is an extremely superficial survey of some of the threats posed by global climate change. For suggestions for further reading, please see below.)

The extent to which these occurrences could play out is yet to be seen. However, they are far from hysterical doomsday scenarios. When we hear that the global air temperature has risen as much as .75 C in the past century, .5 C of this in the past 25 years, and that "overall, the 2001 temperature [the warmest on record] extends the unusual global warming of recent decades," (Hansen, pp 275), we should keep in mind that the last ice age occurred when the global temperature was 3 to 5 C below current temperatures (Shneider, pp 28). That is to say, the rises in temperature that have corresponded strikingly with the increasing emission of carbon dioxide are already quite substantial. Perhaps most terrifying, I have also been told that carbon dioxide can stay in the atmosphere for 50-80 years before it begins to act. This would mean that the trends observed currently are in fact reflective of industry from 1920-50, when emissions were much lower. This would suggest that even if we were stopped industry completely today, we would continue to observe the current trends for the next 50 to 80 years (Pat Barnes, personal communication, 1999).

It is true that the costs of changing our carbon dioxide emissions patterns are more difficult that simply sacrificing our Sunday mornings and giving up adultery. We are heavily dependent on industry and very few Americans would truly be willing to stop in their tracks. However, there are many feasible and realistic alternatives to our current practices as proposed by the Intergovernmental Panel for Climate Change (IPCC, and the Kyoto Protocol (, just to name some of the most well-known. Even acts such as a higher gasoline tax would be oppressive to some extent, but I believe would give more impetus to explore alternative energy sources and to reduce our energy output. Although our goals should remain high, emission reduction of any sort would be beneficial. Even if we are wrong, the worst thing that could happen is that we clean up our act.

Literature Cited:

Hansen, J., Ruedy, R., Sato, M., Lo, K., "Global Warming Continues" Science 2002, vol.
295, p. 275

Philander, S. George. Is the Temperature Rising?: The Uncertain Science of Global
Warming. Princeton University: New Jersey. 1998

Schneider, Stephen H. Global Warming: Are we Entering the Greenhouse Century?
Sierra Club Books: San Francisco. 1989

Hansen, J., Ruedy, R., Sato, M., Lo, K., "Global Warming Continues" Science 2002, vol.
295, p. 275

Quay, Paul, "CLIMATE CHANGE: Enhanced: Ups and Downs of CO2 Uptake" Science
2002, vol. 298, pp. 2344-2346.

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last updated 3/26/03