In the general public discourse the climate change debate has been, so far, confined almost entirely to the greenhouse gas issue. Our economycarbon footprint utterly dominates all climate change discussions. In actual fact there are several major influences acting on the global climate in terms of raising or lowering atmospheric temperatures. The warming induced by greenhouse gases, such as carbon dioxide and methane, is the first such influence.
However, while the physics of the greenhouse effect are clear, the chain of causality between greenhouse gas accumulation in the atmosphere and specific weather patterns is not fully understood. At this time the actual consequences of such accumulation cannot be accurately predicted in terms of timing and impact. The second influence comes from periodic variations in the earth orbit around the sun and in the inclination of its axis. These cyclical variations have been relatively well correlated with past ice ages and warmer inter-glacial periods.
According to some recent published research in this area our planet would currently be sliding into another cold period or ice age, although the timing is hard to pin down. The third influence, which has come into prominence only recently, is solar activity as manifested through the sunspot cycle. For the earth, a high sunspot count means warming, a low count cooling. Although the basic cycle has an average periodicity of eleven years, there are also long term variations which are not well understood.
Sunspot activity has just reached a low which may or may not be significant. But if this low persists, significant cooling can be expected. One can conclude that the overall picture is becoming increasingly ambiguous. Greenhouse gas accumulation due to the use of fossil fuels is no longer the only story in town, nor is warming the inevitable future outcome.
The purpose here is not to claim that greenhouse gas accumulation is not significant. It is to warn that other influences are in play which can be equally important, and that our scientific understanding must be increased before major economic measures, such as a tax on carbon emissions, are implemented. One such measure, a so-called cap and trade scheme, is currently under discussion in the US Congress.
Such a scheme has considerable drawbacks. First, it amounts to a highly regressive tax on energy, which will disproportionally affect the lower income fractions of the population. Second, it introduces huge market distortions which vastly complicate efforts to deal with the gradually increasing price and reduced availability of petroleum. To be successful, such efforts require first and foremost a realistic and workable long-term energy strategy, the elaboration of which must precede any large-scale government intervention in the energy area.
The US government at this time does not have such a strategy, which, as far as its impact on climate is concerned, must rest on a much better scientific understanding of the various influences on climate listed above. Funding to increase and test this understanding will have a far greater impact than any of the currently proposed schemes to reduce carbon emissions. Until such understanding is on more solid footing, there is no valid justification for major initiatives in economic policy on climate change grounds.