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Module 4.3 Long-term global scenarios - Intergovernmental Panel on Climate Change
6 (IPCC)

In order to provide plausible pictures of future emissions of greenhouse gases, the IPCC developed
four families of scenarios, based on an extensive assessment of the literature, six alternative modelling
approaches and an “open process” that solicited wide participation and feedback from many groups
9-12 December, 2013 as well as to assess the associated uncertainties.
and individuals. The scenarios provide a basis for analysing how drivers may influence future emissions,

The four basic storylines are:

A1. A future world of very rapid economic growth, global population that peaks in the middle of the
2100s and declines thereafter, and rapid introduction of new and more efficient technologies. Major
underlying themes are convergence among regions, capacity building and increased cultural and social
interactions, with a substantial reduction in regional differences in per capita income.

A2. A very heterogeneous world emerges; the underlying theme is self-reliance and preservation of
local identities. Fertility patterns among regions converge very slowly, which results in continuously
increasing global population. Economic development is primarily regionally oriented, and per capita
economic growth and technological changes are more fragmented and slower than in other story lines.

Figure 3 IPCC Scenarios

Global

A1 B1
social and
Economic environmental
A2 B2
B2

Regional

Population
economy environment
energy use land use
technology

20 Scenario Development and Analysis