Report from the President

Accumulating evidence indicates that increasing concentrations of greenhouse gases, primarily carbon dioxide, are raising average temperatures, acidifying and raising the level of oceans, and accelerating natural rates of carbon dioxide emissions. Uncertainties abound, but the carbon dioxide concentration in the earth’s atmosphere has risen by 31 percent since 1850 and now exceeds levels experienced over the past 420,000 years. Recent estimates from North America (for 2003) indicate that its anthropogenic carbon dioxide emissions (mainly from burning fossil fuels) were about 1856 million metric tons per year, or about a quarter of all such global emissions.