The case for reducing
greenhouse gas emissions
despite scientific uncartainty

Scientific uncertainty over climate change has led some people to doubt the need for a vigorous policy response. Although most scientists believe that human activities are changing the climate, they do not agree on the rate at which it will occur, nor on its specific impacts (fact sheets 1 and 9). This makes it difficult to put a price tag" on either climate change or on policies to prevent it. Nevertheless, the seriousness of the potential damage and the availability of cost-effective policies are strong arguments for taking immediate action to minimize climate change.

Action is necessary because the damage caused by climate change may be catastrophic and irreversible. Estimates of the probable damage from climate change vary widely, from moderate to overwhelming. However, if the earthâs surface warms by several degrees centigrade over the next 100 years as predicted, it seems clear that millions of people would become vulnerable to the effects of famine, drought, coastal flooding, and more. Nasty surprises, such as changes in certain ocean currents that strongly influence regional weather patterns, could not be ruled out. Once such disasters started to occur, it would take at least several generations before measures to reverse climate change could have significant results. The money spent on taking action now could be viewed as an insurance premium for protection against a hard-to-measure but potentially devastating risk.

The first cuts in greenhouse gas emissions would be relatively cheap. Some 10% of emissions could be eliminated by raising industrial and energy efficiency and by removing counter-productive policies, such as subsidies for clearing forests. The longer such steps are delayed, the more expensive it will become to achieve identical results with future policies. Furthermore, by the time these early reductions are completed and more expensive decisions must be made, the scientific evidence concerning climate change should be clearer.

Reducing greenhouse gas emissions would have additional benefits unrelated to climate change. Fuel efficiency would save money. Lower emissions of pollutants from factories and automobiles would improve air quality in urban centres and reduce acid rain. Putting a stop to deforestation would reduce soil erosion, offer aesthetic and economic benefits, and protect biodiversity and subsistence forest dwellers. One study suggested that while a hypothetical carbon tax might cost Norway 2.75% of its GNP in the year 2010, 70% of that cost would be recouped through such non-climate benefits.1

For further reading:

David Pearce, et. al., "Blueprint 2: Greening the World Economy", London: Earthscan (1991).

Notes:

1 Glomsrod, S. et al. "Stabilization of Emissions of CO2: A Computable General Equilibrium Assessment", Central Bureau of Statistics,

Oslo (1990).

Last revised 1 May 1993 by the Information Unit on Climate Change (IUCC), UNEP, P.O. Box 356, CH-1219 Ch‰telaine, Switzerland. Tel. (41 22) 979 9111. Fax (41 22) 797 3464. E-mail iucc@unep.ch.