Methane is a naturally occurring greenhouse gas. Although it is less abundant than carbon dioxide, its global warming potential is over ten times higher. The main sources of methane are extraction and use of fossil fuels, landfill and livestock. There are concerns that climate change has the potential to trigger the release of large amounts of methane, currently stored in ocean beds and permafrost.
Feedbacks from the methane cycle (for example, increased emissions from wetlands and melting permafrost which could further warm climate) are not included in UKCP09; they may be significant but are not quantified sufficiently well to include with any confidence.
Table 2.1 provides a list of the constituents included, and not included, in the UKCP09 probabilistic projections.
A discussion of sources of uncertainty in the UKCP09 probabilistic projections is available in Annex 2.4 of the UKCP09 Climate change projections report.
Find out more
- IPCC Fourth Assessment Report, Working Group 1 report The Physical Science Basis , Chapter 7.4.1
- IPCC Fourth Assessment Report, Working Group 1 report The Physical Science Basis , Chapter 2.3.2