This paper discusses the UNEP Greenhouse Gas Abatement Costing Project
with particular emphasis on the national assessments of CO2 abatement
cost for developing countries. A methodological framework was develop
ed and country studies were conducted for 10 countries. National margi
nal abatement cost curves for the short-term (25% reduction from basel
ine by 2005 to 2010) and long-term (50% reduction from baseline by 202
0 to 2030) targets are presented and discussed. The cost curves for th
e selected countries exhibit a number of similarities. The paper exami
nes critically how the main scenario assumptions about energy/GDP inte
nsity and energy-efficiency improvement influence the assessed abateme
nt potential and costs. The treatment of 'no regrets' options in the b
aseline and abatement cases is discussed in relation to a developing c
ountry planning context. The issue of comparability between assessment
s from different countries is addressed. Even with uniform assumptions
(discount rates, oil prices etc) for the group of countries as a whol
e, comparability within the UNEP project is shown to be a complex conc
ept which involves national differences in the projection of economic
and energy system development and the use of different modelling appro
aches.