ABSTRACT

It is now widely recognised that large scale reductions in carbon dioxide (CO2) emissions are required during this century in order to limit the extent of climate change modification. Anthropogenic CO2 emissions are largely a result of burning fossil fuels (constituting 80 per cent of such emissions). Once in the atmosphere, CO2 acts as a greenhouse gas, causing: mean global temperatures and sea levels to rise; precipitation patterns to change; the frequency and severity of extreme weather events to be potentially enhanced; and the acidification of the oceans – with widespread implications for global support systems which underpin existing human activities (IPCC 2001 and 2001a; Schellnhuber et al. 2006). Fossil fuel combustion currently accounts for annual emissions into the Earth’s atmosphere of about 23 x 109 tonnes CO2 (or 23 Giga tonnes, Gt). This represents a global increase in anthropogenic CO2 emissions of 70 per cent between 1971 and 2002 (IEA 2004).