Future greenhouse gas emissions

Future anthropogenic changes in global climate will be determined by future patterns of emissions of greenhouse gases. Possible future changes in emissions are described and analysed in several different ways: scenarios, profiles and mitigation regimes. Mitigation regimes are formulated in many different ways, the main distinctions being between targets and reduction measures.

Scenarios

Scenarios are defined as sets of emissions over time, based on a consistent view of socio-economic changes.

The successive IPCC assessment reports have used scenarios of future growth: the BaU (business as usual) scenario in 1990; the IS92a,b,c,d,e,f scenarios in 1995 and the SRES scenarios (documented in the Special Report on Emission Scenarios) in 2001. The IPCC scenarios are specifically intended to show what could happen in the absence of intervention and specifically exclude scenarios that include mitigation of climate change.

Profiles

Profiles are specifications over time of future changes, often specified as simple mathematical functions, without being referenced back to specific actions. Profiles give indications of the types of behaviour, rather than making specific projections or recommendations about the future. Examples are the 1% per annum CO2 growth used in the AMIP intercomparison, and quoted in the 3rd IPCC assessment.

Profiles of CO2 concentrations, stabilising in future centuries were analysed to determine the emission reductions that would be needed to achieve such stabilisation. The results were reported in the 1995 IPCC report on Radiative Forcing of Climate and documented in detail in CSIRO Division of Atmospheric Research Technical paper no 31.

Mitigation regimes

Framework Convention on Climate Change (FCCC) FCCC as pdf
The FCCC has come into effect after being ratified by the requisite number of nations. It has the overall objective of stabilising greenhouse gas concentrations at levels that avoid dangerous interference with the climate while allowing economic development.
Brazilian proposal
In the course of negotiations leading to the Kyoto Protocol, Brazil proposed that emission reduction targets (for developed nations) should be set on the basis of nations' relative responsibility for global warming. This proposal is being considered by the Subsidiary Body for Scientific and Technical Advice to the FCCC. (MORE - with further external links)
Contraction and convergence Link to Global Commons Institute
This approach proposes overall redutions in global greenhouse gas emissions and convergence towards equal per capita emissions. A proposal along these lines was tabled by France (converging to 2 tonnes of carbon per person per year by 2100) during the negotiations leading to the Kyoto Protocol.
Tryptique
The tryptique principles define different targets for different sectors of the economy. These principles form the basis for setting different targets for EU nations with the EU "bubble" target specified in the Kyoto Protocol.
McKibbin-Wilcoxen ANU e-print
This approach defines a framework for managing emissions through a mix of short-term and long-term permits. It is designed to achieve mitigation in a way that is robust with respect to uncertainties in climate change which leads to minimal economic transfers. The proposal defines principles, rather than specific targets.
Other
Many variations on these approaches have been proposed, with a number of nations (e.g. UK) looking towards large reductions in emissions by the middle of this century.

Other external links

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This page, its contents and style, are the responsibility of the author and do not represent the views, policies or opinions of The University of Melbourne.

Ian Enting: last change 10/9/04.