Kyoto Protocol

Background and evolution

The UNFCCC, agreed at Rio in 1992, set the goal of stabilising greenhouse gas concentrations but contained no binding numbers. By the mid-1990s it was clear that voluntary efforts would not be enough. At the first Conference of the Parties in Berlin (1995), countries agreed in the "Berlin Mandate" to negotiate binding commitments for developed countries only, in line with common but differentiated responsibilities.

The outcome, adopted at COP3 in Kyoto, gave each listed industrialised country a specific target. Entry into force required ratification by 55 parties accounting for 55% of developed-country CO2 emissions in 1990. The United States signed but never ratified; the treaty finally entered into force in 2005 after Russia ratified. Detailed rules were finalised in the Marrakesh Accords of 2001.

Key features and provisions

• Annex B targets: differentiated cuts, for example 8% for the European Union and 6% for Japan, relative to 1990.
• Flexibility mechanisms: allowed countries to meet part of their targets abroad, where cuts were cheaper.
• Emissions trading: Annex B countries could trade assigned amount units.
• Clean Development Mechanism (CDM): developed countries could finance emission-reducing projects in developing countries and earn certified emission reductions (CERs).
• Joint Implementation: similar projects between Annex B countries.
• Compliance system: a committee with enforcement and facilitative branches.
• Sinks: forestry and land-use activities could count towards targets.