A Global Problem: Responsibility for Climate Change.
Over the past century, human agricultural and industrial activities have led to the buildup of CO2 and other greenhouse gases. These gases are trapping yet more of the earth's outgoing radiation, leading to an enhanced greenhouse effect and a warmer earth.
Because CO2 and other greenhouse gases are so long-lived in the atmosphere, enhanced greenhouse warming can be expected to persist for centuries. The impacts - many of which are effectively irreversible - will affect everyone on earth. Human health, patterns and intensity of precipitation, water and food supplies, coastal development, energy supplies, the viability of natural systems: all will be affected if Earth's climate continues to change.
Taking unified global action against climate change, however, has proven contentious. Unequal divisions of resources and emissions between industrial and developing nations has raised many issues over who should pay.
Also due to the unpredictable nature and the limited knowledge we have about atmospheric processes and climate change, scientists are having difficulty coming up with precise predictions about future climate changes. The climate system is complex and scientists still need to improve their understanding of the extent, timing and impacts of climate change, but what we know already alerts us to its dangers. Because we cannot accurately predict the full consequences of global warming, Governments are unwilling to commit billions of dollars to implementing more environmentally friendly solutions, on the basis of such predictions.
But the need to reduce global emissions is becoming increasingly more pressing as reports from the Intergovernmental Panel on Climate Change (IPCC), released in 2001, confirms that "an increasing body of observations gives a collective picture of a warming world with "new and stronger evidence that most of the warming observed over the l