In 1997, the Kyoto conference looked at the issue of global warming and how to reduce the emissions of gases, such as carbon dioxide, that are causing it. It set up a framework that required countries to reduce their emissions of greenhouse gases to an average of 5% below the levels they produced in 1990. This reduction should be reached by 2012.
The Kyoto treaty assigned countries with a level of greenhouse gases that they were permitted to produce. Low CO2 producers can sell their allowances to high CO2 producers. This is called 'carbon trading'.
The treaty, in its original format, was never implemented. Not enough countries would agree to it. Finally, in 2005, a scaled-down version of the treaty was agreed with 1340 countries. This included industrialised countries like the UK and Russia. However the USA, a major producer of greenhouse gases, is still not part of the agreement.
Government groups in the USA argue that the Kyoto agreement is out of date and that efforts should be concentrated onto finding alternatives to carbon-based fossil fuels.
Some organisations, such as the Intergovernmental Panel on Climate Change, believe that the reductions in emissions are not large enough and argue that they should be cut by 60%. But others argue that such big cuts would have a harmful effect on economic sustainability.