After a decade of speculation and debate, there is now a general scientific consensus that rising greenhouse gas levels in the earth’s atmosphere will result in significant climate change over the next century. The recent statement by the Intergovernmental Panel on Climate Change (Watson et al. 1995) that 'the observed increase in global mean temperature over the last century (0.3-0.6°C) is unlikely to be entirely due to natural causes, and that a pattern of climate response to human activities is identifiable in the climatological record' is a strong endorsement of this conclusion. The recently negotiated Kyoto Protocol to the United Nations Framework Convention on Climate Change recognizes the influence of greenhouse gas concentrations on global warming and requires signatory countries to commit to significant reductions in emissions in the near future, further evidence of a growing acknowledgment that climate change is a reality.