Emissions Scenarios - IPCC

An Overview of Scenaiios 171
within and across altemative scenarios and to enhance
the consistency in assumptions for different parameters.
• To make it easier to explain the scenarios to the various
user communities by providing a narrative description
of altemative futures that goes beyond quantitative
scenario features.
• To make the scenarios more useful, in particular, to
analysts contributing to IPCC WGs II and III. The
demographic, social, political, and technological contexts
described in the scenario storylines are all-important in
the analysis of the effects of policies to either adapt to
climate change or to reduce GHG emissions.
• To provide a guide for additional assumptions to be
made in detailed climate-impact and mitigation
analyses, because at present no model or scenario can
possibly respond to the wide variety of infomiational
and data needs of the different user communities of
long-term emissions scenarios.
The four scenario families presented in this report are
representative of a broad range of scenarios found in the
literature, but they are not directly based on any particular
published scenario taxonomy or set of scenarios. Rather, the
storylines of each scenario family were developed on the basis
Box 4-1: Four SRES World Regions
The six modeling frameworks used to develop the SRES scenarios have different regional aggregations. The writing team
decided to group the various global regions into four "macro-regions" common to all the diiferent regional aggregations across
the six models (Figure 4.2; see Appendix IV, Table IV-1). The individual scenarios were formulated with the respective regional
aggregation of each model. Afterward, the input assumptions and results were summed to correspond to the four macro-regions:
• OECD90 region groups together all member countries of the Organization for Economic Cooperation and Development
as of 1990, the base year of the participating models, and corresponds to the Annex II countries originally defmed in
UNFCCC (1992).
• REF region consists of countries undergoing economic reform and groups together the East and Central European
countries and the Newly bidependent States of the former Soviet Union; it roughly corresponds to Annex I outside the
Annex II countries as defined in UNFCCC (1992).
• ASIA region stands for all developing (non-Annex I) countries in Asia (excluding the Middle East).
• ALM region stands for the rest of the world and corresponds to developing (non-Annex I) countries in Africa, Latm
America, and Middle East.
In other words, the OECD90 and REF regions together roughly correspond to Annex I or industrialized (developed) countries
(IND), while the ASIA and ALM regions together roughly correspond to the non-Annex I, or developing countries (DEV).
Developing, or non-Annex I countries (i.e., ASIA and ALM), are sometimes referred to hi the text as the "South" to distinguish
them from the mdustriahzed, or Annex I countries, of the "North" (i.e., OECD90 and REF). A detailed description of each
region is provided in Appendix Ш.
1 NAM North America
2 LAM Latin Amenca and the Canbbean
3 AFR Sub-Saharan Africa
4 MEA Middle East and North Africa
5 WEU Westem Europe
6 EEU Central and Eastem Europe
7 FSU Newly independent states of
the former Soviet Union
8 CPA Centtally planned Asia and China
9 SAS South Asia
10 PAS Other Pacific Asia
1! PAD Pacific OECD
Figure 4-2: SRES world
regions ALM, ASIA,
OECD90, and REF The
developing (DEV) countries,
comprising the ALM and
ASIA regions, roughly
correspond to non-Aimex I
countries of the UNFCCC
(1992). The industrialized
(IND) countries, comprising
the OECD90 and REF
regions, roughly correspond to
Annex I countries of the
UNFCCC.