Thematic Guide to Integrated Assessment Modeling

[HOME] [BOTTOM]

Climate and ecosystem protection requires binding emission targets:

the specific tasks after Rio (II)

Wilfrid Bach, Atul K Jain
Climate and Energy Research Unit, Department of Geography, University of Münster, Robert Koch-Straße 26, D-4400 Münster, Germany
Received 3 November 1992

Abstract. The specific tasks after the UN Conference on Environment and Development (UNCED) in Rio will involve the implementation of an effective policy for climate and ecosystem protection. This requires clarification of the questions: what has to be done by whom at what time and how?

The question 'what has to be done' depends on the ultimate objectives of the Climate Convention, which are defined as stabilising the greenhouse gas concentrations in the atmosphere at nondangerous levels for the climate system, allowing ecosystems time to adapt, ensuring sufficient food production, and enabling economic development in a sustainable manner. A goal-oriented mean global warming ceiling of ~2°C by 2100, relative to 1860, and a critical mean global rate of temperature change of ~0.1°C per decade could satisfy the objective of the Convention. Various combinations of greenhouse gas emission reductions could reach the Convention's objectives. For example, global emission reductions of ~70% for CO2, 5% for CH4, 50% for N2O, and 100% for CFCs and HCFC-22 over the period 1990-2100 in the modified Scenario Climate Protection of the Enquete-Commission of the German Parliament (ECGP) would ensure that the global warming ceiling of 2°C is not exceeded. In contrast, the low-emissions scenario of the Intergovernmental Panel on Climatic Change (IPCC) - Scenario IS92c with emission reductions of ~23% for CO2 and 100% for CFCs, but increases of 8% for CH4, 6% for N2O, and 788% for HCFC-22, exceeds the upper warming ceiling of 2°C and therefore requires greater reductions.

The question 'by whom has it to be done' touches upon the secret of a successful reduction policy, namely a fair burden sharing among the main actors. In an accompanying paper we have used about a dozen criteria and statistical methods to group the world's 179 countries. Using an emission cutoff level of >10 Mt a-1 per country for the main gas CO2, we finally arrived at 69 countries which accounted for 98% of the global emissions of 1987. The 69 countries were allocated to six groups: economically strong, economically less strong, and economically weak industrialized countries (ICs), Arabic oil-producing countries, countries in transition, and developing countries (DCs). The reduced number of actors on the basis of comparable burden sharing is very good news, because it should enormously facilitate the forthcoming negotiations on setting legally binding emission targets.

The question 'at what time has it to be done' addresses the critical problem of setting targets which must be legally binding if the Convention's objectives with the defined climate-protection goals are to be achieved. Climate modelling provides only the required global targets; thus they must still be allocated to the six groups of countries on the basis of specific criteria. For the modified Scenario Climate Protection of the ECGP we obtain, for example, the following required CO2 emission changes relative to 1987: worldwide a stabilisation in 2005 at the 1987 level, and reductions of 15%, 50%, and 70% in 2020, 2050, and 2100, respectively; for economically strong ICs reductions of 25%, 40%, 80%, and 90% in 2005, 2020, 2050, and 2100, respectively; for DCs increases of 50%, 35%, and 32% in 2005, 2020, and 2050, respectively, and a reduction of 25% by 2100. These and the other group targets are compatible with the objective of the Climate Convention and could therefore serve as guidelines for the upcoming negotiation rounds.

Finally, the question 'how can it be done' relates to individual countries, states, and municipalities. The measures to be taken for achieving the reduction commitments are of a technical, legal, fiscal, and organisational nature, of which some are universally applicable whereas others are country specific. We show in detail how the German commitment of a 25%-30% CO2 reduction by 2005 (compared to 1987) can be achieved. We present an evaluation of the effectiveness of measures taken to reduce CO2 emission, identify robust no-regret measures, and discuss the implementation of an action-oriented no-surprise policy.

[SEDAC] [TOP]

Sources

Parson, E.A. and K. Fisher-Vanden, Searching for Integrated Assessment: A Preliminary Investigation of Methods, Models, and Projects in the Integrated Assessment of Global Climatic Change. Consortium for International Earth Science Information Network (CIESIN). University Center, Mich. 1995.

Suggested Citation

Consortium for International Earth Science Information Network (CIESIN). 1995. Thematic Guide to Integrated Assessment Modeling of Climate Change [online]. University Center, Mich.
CIESIN URL: http://sedac.ciesin.org/mva/iamcc.tg/TGHP.html