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Forcing Agents Underlying Climate Change: Page 10 of 11

Submitted Testimony: 8. Communication.

Our paper on the alternative scenario (1) was reported with a variety of interpretations in the media. As I discuss in an open letter (21), this may be unavoidable, as the media often have editorial positions and put their own spin on news stories. Overall, the media correctly conveyed the thrust of our perspective on climate change. Furthermore, I suggest in my open letter that the Washington Post editorial on our paper (23) represented an astute assessment of the issues.

A basic problem is that we scientists have not informed the public well about the nature of research. There is no fixed "truth" delivered by some body of "experts". Doubt and uncertainty are the essential ingredient in science. They drive investigation and hypotheses, leading to predictions. Observations are the judge.

Of course, some things are known with higher confidence than others. Yet fundamental issues as well as details are continually questioned. The possibility of finding a new interpretation of data, which provides better insight into how something in nature works, is what makes science exciting. A new interpretation must satisfy all the data that the old theory fit, as well as make predictions that can be checked.

For example, the fact that the Earth has warmed in the past century is well established, and there is a high degree of confidence that humans have been a major contributor to this warming. However, there are substantial uncertainties about the contributions of different forcings and how these will change in the future.

In my open letter (21) I note the potential educational value of keeping an annual public scorecard of measured changes of (1) fossil fuel CO2 emissions, (2) atmospheric CO2 amount, (3) human-made climate forcing, and (4) global temperature. These are well-defined quantities with hypothesized relationships. It is possible to make the science understandable, and it may aid the discussions that will need to occur as years and decades pass. It may help us scientists too.

9. Summary: A Brighter Future.

The "business-as-usual" scenarios for future climate change provide a useful warning of possible global climate change, if human-made climate forcings increase more and more rapidly. I assert not only that a climatically brighter path is feasible, but that it is achievable via actions that make good sense for other reasons (22, 24). The alternative scenario that we have presented does not include a detailed strategic plan for dealing with global warming. However, it does represent the outline of a strategy, and we have argued that its elements are feasible.

It is impractical to stop CO2 from increasing in the near term, as fossil fuels are the engine of the global economy. However, the decline of the growth rate of CO2 emissions from 4 to 1%/year suggests that further reduction to constant emissions is feasible, especially since countries such as the United States have made only modest efforts at conservation. The potential economic and strategic gains from reduced energy imports themselves warrant the required efforts in energy conservation and development of alternative energy sources. It is worth noting that global CO2 emissions declined in 1998 and again in 1999, and I anticipate that the 2000 data will show a further decline. Although this trend may not be durable, it is consistent with the alternative scenario.

The other requirement in our alternative scenario is to stop the growth of non-CO2 forcings, which means, primarily, air pollution and methane. The required actions make practical sense, but they will not happen automatically and defining the optimum approach requires research.

A strategic advantage of halting the growth of non-CO2 forcings is that it will make it practical to stop the growth of climate forcings entirely, in the event that climate change approaches unacceptable levels. The rationale for that claim is that an ever-growing fraction of energy use is in the form of clean electrical energy distributed by electrical grids. If improved energy efficiency and non-fossil energy sources prove inadequate to slow climate change, we may choose to capture CO2 at power plants for sequestration.

Global warming is a long-term problem. Strategies will need to be adjusted as we go along. However, it is important to start now with common-sense economically sound steps that slow emissions of greenhouse gases, including CO2, and air pollution. Early emphasis on air pollution has multiple immediate benefits, including the potential to unite interests of developed and developing countries. Barriers to energy efficiency need to be removed. Research and development of alternative energies should be supported, including a hard look at next generation nuclear power. Ultimately strategic decisions rest with the public and their representatives, but for that reason we need to make the science and alternative scenarios clearer.

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