Humans are now making unprecedented changes to the global environment.
Economic development has been fostered by the use of fossil fuels but the
accompanying accumulation of greenhouse gases, particularly carbon dioxide
and methane, has implications for the world's climate (Box).1 Since the 1850s when
temperature records began, the world has warmed by approximately 0.6°C,
largely in the last 3 decades. The United Nations Intergovernmental Panel
on Climate Change (IPCC) projects an increase of between 1.8°C and 5.8°C
and an increase in sea levels between 9 and 88 cm during the next century.1 Warming is likely to be greater at the poles than
at the equator. The residence time in the atmosphere of carbon dioxide exceeds
100 years; therefore, our actions affect the prospects of future generations.