Last year in Rio de Janeiro, Brazil, world leaders and citizens from more than 200 countries came together to confront the global ecological crisis. The Earth Summit aroused the hopes and dreams of people around the world and set in motion ambitious plans to address the planet's deepest environmental threats. We shared a common mission: to provide a higher quality of life for ourselves and a brighter future for our children.

At the Earth Summit, the United States joined other countries in signing the Framework Convention on Climate Change, an international agreement to address the danger of global climate change. The Convention has been signed by 161 countries and has been ratified by 31 of those countries. The objective of the Convention was stated to:

"...achieve ... stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. Such a level should be achieved within a time frame sufficient to allow ecosystems to adapt naturally to climate change, to ensure that food production is not threatened, and to enable economic development to proceed in a sustainable manner."
The international community rallied around the threat of climate change because scientists agree that the risk is real. There is no doubt that human activities are increasing the atmospheric concentrations of greenhouse gases, especially carbon dioxide, methane, and nitrous oxide. All theoretical models predict that these increases in greenhouse gas concentrations will cause changes in climate both regionally and globally -- with adverse consequences likely for human health, as well as to ecological and socio-economic systems. The best current predictions suggest that the rate of climate change will far exceed any natural climate changes that have occurred during the last 10,000 years. Of course, there are uncertainties regarding the precise magnitude, timing and regional patterns of climate change. But any human-induced climate change that does occur will not be easily reversed for many decades or even centuries because of the long atmospheric lifetimes of the greenhouse gases and the inertia of the climate system.

Our capacity to act in the face of long-term threats is illustrated in a story about a French general who asked his gardener to plant a tree. "Oh, this tree grows slowly," the gardener said. "It won't mature for a hundred years." "Then there's no time to lose," the general answered. "Plant it this afternoon."

Global climate change is a long term problem that will require years of sustained effort. The time for action is now.