Conscious Choice: How Certain is Certain Enough?

July 1999

How Certain is Certain Enough?

by Dave Aftandilian

Do we know for sure that climate change is happening, and that human activities are the cause of it? That’s the question policymakers would like answered before they commit their countries to reducing emissions of the greenhouse gases like carbon dioxide that cause climate change. So far, it’s not a question science can answer definitively. Nevertheless, except for a handful of skeptics (several of whom are well-funded by the fossil fuel industry), most climate scientists agree that there is a problem and that we should act now to deal with it, before it is too late to take the most effective remedial measures.

We do know that the 1990s have seen seven of the ten warmest years since the mid-nineteenth century (World Meteorological Association) and that average global surface temperatures for 1998 were higher than in any year since record keeping began in 1860 (according to the National Aeronautics and Space Administration, the National Oceanic and Atmospheric Administration, and other groups).

In its latest comprehensive report, released in 1996, the Intergovernmental Panel on Climate Change (IPCC) concluded that "the balance of evidence suggests that there is a discernible human influence on climate." The IPCC is the preeminent international organization studying climate change; its latest report was based on research by 400 scientists in 26 countries and was peer-reviewed for accuracy by 500 other scientists from 40 countries.

The American Geophysical Union released a position statement in January of this year stating that "Atmospheric concentrations of carbon dioxide and other greenhouse gases have substantially increased as a consequence of fossil fuel combustion and other human activities. . . .Increasing concentrations of carbon dioxide and other greenhouse gases affect the Earth-atmosphere energy balance, enhancing the natural greenhouse effect and thereby exerting a warming influence at the Earth’s surface."

These conclusions are not certain, and probably never will be; science just doesn’t work that way. On the other hand, the potential risks of inaction are great, including rising sea levels flooding low-lying areas, more frequent bouts of severe weather like hurricanes, drastic changes in rainfall, droughts withering crops and forests in some parts of the world, and increasing spread of tropical diseases. As Henry Jacoby, Ronald Prinn, and Richard Schmalensee put it in the July/August 1998 issue of Foreign Affairs, "The current debate about detection [of human influence on climate] does not justify inaction. It would be irresponsible to ignore such a risk, just as it would be irresponsible to do nothing when you smell smoke at home until and unless you see flames."

Even business leaders are urging that we take precautionary actions now. Sir John Browne, Group Chief Executive of BP Amoco, has said that "There is now an effective consensus that there is a discernible human influence on the climate and a link between the concentration of carbon dioxide and the increase in temperature. . . .[I]t would be unwise and potentially dangerous to ignore the mounting concern. . . .[We] do need to take precautionary action now." Jeroen van der Veer, a Group Managing Director of Royal Dutch/Shell, agrees: "We believe it is right to take precautionary steps now to reduce greenhouse gas emissions and to begin to plan long-term for greater use of renewable resources." And G. Mustafa Mohatarem, Chief Economist for General Motors, believes "There is sufficient information that some degree of precautionary, prudent, and cost-effective actions are called for."

Considering that the actions we need to take to cope with climate change can actually improve our economy, increasing efficiency and creating more jobs, it seems that one thing is certain — acting now to avert the potentially very serious risks associated with climate change is truly a "no regrets" policy.

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