Climate change is a global issue and must therefore be primarily dealt with at a global level. The objective of international negotiations since the agreement of the UN’s 1997 Kyoto Protocol has been to reduce greenhouse gas (GHG) emissions, thereby stabilising the climate at levels which avoid the impacts of dangerous climate change, and on ensuring that agreements are equitable in terms of the effort contributed by developing and developed countries.

The UK’s contribution to reducing global emissions is set out in the Climate Change Act and in the CCC’s first report to Parliament, published in December 2008. This set out the CCC’s analysis that the UK should reduce emissions by at least 80% in 2050 in order to contribute (alongside action from other countries) to stabilising rises in global temperatures to around 2 degrees in 2050. This target should apply across all sectors of the economy that produce emissions and to all greenhouse gases.

The UK’s 80% GHG emission reduction objective is a reasonable contribution to a global objective to cut GHG emissions by 50% or more below current levels by 2050.

The Committee considered these reductions to be the minimum required in order to reduce the risk of dangerous climate change, based on current understanding that the world should aim to keep central (i.e. 50% probability) estimates of temperature increase by 2100 close to 2°C.

(link to science climate targets section)

 Analysis jointly carried out by the CCC and the Met Office Hadley Centre shows that:

• Reducing global emissions to between 20-24 GtCO₂e in 2050, with a further reduction to between 8 and 10 GtCO₂e by 2100, would keep our central estimate of global temperature rise in 2100 close to 2°C above pre-industrial levels, and reduce the chances of extreme climate change (e.g. a more than 4°C rise by 2100) to a very low level (less than 1%). 

The Committee assessed a range of emissions trajectories before advising that, in order to achieve the climate objective, global emissions should peak in the period before 2020, with 3%-4% annual cuts beyond the peaking year leading to a minimum 50% cut in global emissions by 2050 across all Kyoto gases and all sectors of the economy.

Modelling process for relating emissions pathway to temperature targets

 Source: Met Office Hadley Centre, CCC

As part of this advice, the Committee analysed the contribution of aviation and shipping towards global emissions and advised that both domestic and international aviation and shipping need to be covered by mechanisms to reduce emissions.