The objective of the climate convention that was phrased in general terms was put into specific form in the so-called "Kyoto Protocol" of 1997, in which 38 industrial nations undertook to reduce their emissions of greenhouse gases. Specific reduction targets by 2010 (as compared to the base year of 1990) were defined for six greenhouse gas groups: carbon dioxide (CO2), methane (CH4), laughing gas (N2O), partially halogenated hydrofluorocarbons (HFC), perfluorinated hydrocarbons (PFC) and sulphur hexafluoride (SF6).

The Kyoto Protocol only becomes binding international law if it is ratified by 55 countries which together cause more than 55% of global greenhouse gas emissions. The failure to ratify the protocol by large industrial countries such as the USA, Australia and Russia - which cause enormous volumes of greenhouse gases - prevented it from coming into force for a ling time because the 55% limit was not passed. It was not until the end of 2004 that Russia also ratified the Kyoto Protocol, after which it finally came into force on February 16th, 2005.

According to the Kyoto Protocol, industrialized countries are able to partially reduce their greenhouse gas emissions with targeted projects abroad, or through emissions trading. To do this, the Kyoto Protocol grants the use of so-called flexible mechanisms: the Clean Development Mechanism (CDM), Joint Implementation (JI) and international emissions trading.

These unique instruments allow a country to reduce greenhouse gas emissions in other countries at lower costs than at home. From a certain point of view, the flexible mechanisms represent ecological instruments to reduce greenhouse gases at the lowest possible costs. However, industrialized countries must fulfill a large part of the reduction stipulations through domestic measures, and may only adopt the flexible mechanism as a back-up.