Global Warming

The Kyoto Protocol 247

Table 10.2Greenhouse gases covered by the Kyoto Protocol and their

global warming potentials (GWPs) on a mass basis relative to carbon

dioxide and for a time horizon of 100 years

Greenhouse gas Global warming potential (GWP)

Carbon dioxide (CO 2 )1
Methane (CH 4 )2 3
Nitrous oxide (N 2 O) 296
Hydrofluorocarbons (HFCs) from 12 to 12 000a
Perfluorocarbons (PFCs) from 5000 to 12 000a
Sulphur hexafluoride (SF 6 ) 22200

Table 6.7 from Ramaswamy, V.et al.2001. In Houghton, J. T., Ding, Y., Griggs,
D. J., Noguer, M., van der Linden, P. J., Dai, X., Maskell, K., Johnson, C. A. (eds.)
Climate Change 2001: The Scientific Basis. Contribution of Working Group I to
the Third Assessment Report of the Intergovernmental Panel on Climate Change.
Cambridge: Cambridge University Press.
aRange of values for different HFCs or PFCs – for more information about HFCs

see Moomaw, W. R., Moreira,J. R.et al. 2001. Technological andeconomic

potential of greenhouse gas emissions reduction. In Metz, B., Davidson, O.,

Swart, R., Pan, J. (eds.) 2001.Climate Change 2001: Mitigation. Contribution

of Working Group III to the Third Assessment Report of the Intergovernmental

Panel on Climate Change. Cambridge: Cambridge University Press, Chapter

3 and its appendix.

that are unprecedented in an international treaty and that enable countries
to offset their domestic emission obligations against the absorption of
emissions by ‘sinks’ (e.g. through forestation) or by investment in or
trading with other countries where it might be cheaper to limit emissions.
The emissions controlled by the Protocol are from six greenhouse
gases (Table 10.2) that can be converted into an amount of carbon-
dioxide-equivalent through the use of their global warming potentials
(GWPs) which were introduced in Chapter 3 page 52.
The details of the Protocol were finally agreed at a meeting of the
Conference of the Parties in Marrakesh in October/November 2001.
Much of the detailed discussion related to the inclusion of carbon
sinks, especially from forests and from land-use change. Because of the
large uncertainties regarding the magnitude of such sinks, considerable
doubts were expressed regarding their inclusion in the Protocol arrange-
ments. However, it was agreed that they should be included in a limited
way and detailed regulations were agreed concerning the inclusion of