1.8. Structure of the Report
The report consists of six chapters and 11 appendices. After this introductory
chapter, Chapters 2 and 3 present
the scenario literature review and analysis. Chapters 4
and 5 describe the new SRES scenarios, Chapter
6 summarizes the main findings, and the appendices present the methodologic
approach and statistical background material.
Chapter 2 presents the assessment of anthropogenic GHG
emissions scenarios and their main driving forces based on an extensive literature
review. It describes the unique scenario database developed for this study,
which contains over 400 global and regional scenarios. The chapter presents
the range of emissions from the scenarios in the literature with associated
statistics such, as medians, percentiles and histograms. The main scenario driving
forces are analyzed in the same way, from population and economic development
Chapter 3 reviews the main driving forces of past and
possible future anthropogenic GHG emissions. These include demographic, economic
and social development, changes in resources and technology, agriculture and
land-use change, and policy issues other than those related to climate. The
relationships and possible interactions among the driving forces are highly
complex and heterogeneous. The focus of the chapter is to provide an overview
of the main driving forces and their possible relationships that are particularly
relevant for the SRES scenarios.
Chapter 4 presents the narrative scenario storylines
and the quantification of the main scenario driving forces with the six SRES
IA models. First, an overview of the four storylines is given which describes
their main characteristics, relationships and implications. Then, the 40 scenario
quantifications of the four storylines with the six models are presented. For
each storyline one scenario is designated as a representative marker scenario.
Together the 40 scenarios span the range of scenario driving forces and their
relationships presented in the previous two chapters.
Chapter 5 documents anthropogenic GHG and SO2 emissions
for the 40 SRES scenarios highlighting the four marker scenarios. First, CO2
emissions are presented, followed by other GHGs, and by the assessment of indirect
effects and aerosols. Together the 40 scenarios span the emissions ranges from
the literature and the four marker scenarios jointly characterize both the dynamics
of emissions patterns and their ranges.
Chapter 6 summarizes the main characteristics of the
SRES scenarios and findings and compares the new scenarios with the IS92 set
as well as with other scenarios from the literature. The chapter addresses possible
implications of the new scenarios for future assessments of climate change and
concludes with recommendations from the writing team for user communities.
Finally, 11 appendices conclude the report. They include for example the SRES
Terms of Reference, a technical appendix that describes the six modeling approaches
used to formulate the 40 scenarios, the scenario database and tables with further
statistics that describe the new scenarios.