SRES scenarios: Or, what can we say about the evolution of the global energy-economic system? Anand Patwardhan IIT-Bombay

Anand Patwardhan, IIT-Bombay2 SRES Emissions Climate change Changes in exposure Baseline (or “current”) vulnerability Future vulnerability Exposure Local, regional, sectoral drivers Why SRES?

Anand Patwardhan, IIT-Bombay3 SRES in brief Builds on, and replaces the IS92 scenarios Qualitative: storylines Quantitative: several model-based quantitative scenarios corresponding to each storyline Descriptive (neither desirable nor undesirable) Although no scenario is really value-free No best-guess or business-as-usual scenario (IS92a was often used as a BAU case), no assignment of probability or likelihood to any scenarios

Anand Patwardhan, IIT-Bombay4

5 SRES structure Each SRES storyline represents different demographic, social, economic, technological and environmental developments While storylines start from the same point, they diverge, gradually in irreversible ways Storylines are numbered, to avoid interpretations that may reflect a value judgment (ex: “green and clean”) Each scenario represents a specific quantitative interpretation of one storyline (note: multiple interpretations are possible) These quantitative interpretations are obtained using a range of energy-economic models

Anand Patwardhan, IIT-Bombay6 Scenarios Four storylines (A1, A2, B1, B2) Six scenario groups – one each for A2, B1, B2, and three for A1 (A1F1 – fossil fuel intensive, A1B – balanced, A1T – predominantly non-fossil) Six modeling teams produced a total of 40 scenarios across these six groups

Anand Patwardhan, IIT-Bombay7

8 A1 storyline The A1 storyline and scenario family describes a future world of very rapid economic growth, low population growth, and the 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. Primary features: Strong commitment to market-based solutions. High savings and commitment to education at the household level. High rates of investment and innovation in education, technology, and institutions at the national and international levels. International mobility of people, ideas, and technology

Anand Patwardhan, IIT-Bombay9 A2 storyline The A2 storyline and scenario family describes a very heterogeneous world. The underlying theme is self- reliance and preservation of local identities. Fertility patterns across regions converge very slowly, which results in high population growth. Economic development is primarily regionally oriented and per capita economic growth and technological change are more fragmented and slower than in other storylines Primary dynamics: The A2 world “consolidates” into a series of economic regions. Self-reliance in terms of resources and less emphasis on economic, social, and cultural interactions between regions are characteristic for this future. Economic growth is uneven and the income gap between now-industrialized and developing parts of the world does not narrow, unlike in the A1 and B1 scenario families

Anand Patwardhan, IIT-Bombay10 B1 storyline The B1 storyline and scenario family describes a convergent world with the same low population growth as in the A1 storyline, but with rapid changes in economic structures toward a service and information economy, with reductions in material intensity, and the introduction of clean and resource-efficient technologies. The emphasis is on global solutions to economic, social, and environmental sustainability, including improved equity, but without additional climate initiatives Primary dynamics: high level of environmental and social consciousness combined with a globally coherent approach to a more sustainable development. Economic development in B1 is balanced, and efforts to achieve equitable income distribution are effective

Anand Patwardhan, IIT-Bombay11 B2 storyline The B2 storyline and scenario family describes a world in which the emphasis is on local solutions to economic, social, and environmental sustainability. It is a world with moderate population growth, intermediate levels of economic development, and less rapid and more diverse technological change than in the B1 and A1 storylines. While the scenario is also oriented toward environmental protection and social equity, it focuses on local and regional levels Primary dynamics: The B2 world is one of increased concern for environmental and social sustainability compared to the A2 storyline. Increasingly, government policies and business strategies at the national and local levels are influenced by environmentally aware citizens, with a trend toward local self-reliance and stronger communities. International institutions decline in importance, with a shift toward local and regional decision-making structures and institutions. Human welfare, equality, and environmental protection all have high priority, and they are addressed through community-based social solutions in addition to technical solutions, although implementation rates vary across regions

Anand Patwardhan, IIT-Bombay12 Another four-way view at the global level

Anand Patwardhan, IIT-Bombay13 Primary drivers Demographic change (population and population structure) Social and economic development Rate and direction of technological change

Anand Patwardhan, IIT-Bombay14 Population

Anand Patwardhan, IIT-Bombay15 Economic development All scenarios describe futures that are more affluent than today (10-fold to 26-fold increase in gross world product by 2100) The A1 scenario family with a “harmonized” gross world product of US$529 trillion (all values in 1990 US dollars unless otherwise indicated) in 2100 delineates the SRES upper bound, whereas B2 with “harmonized” US$235 trillion in 2100 represents its lower bound. The range of gross world product across all scenarios is even higher, from US$197 trillion to 550 trillion by 2100 A narrowing of income differences among world regions is assumed in many scenarios – two families, A1 and B1 explicitly explore pathways to close income gaps in relative terms

Anand Patwardhan, IIT-Bombay16 Structural change in the energy system

Anand Patwardhan, IIT-Bombay17 Global land-use change

Anand Patwardhan, IIT-Bombay18 Energy – income linkage

Anand Patwardhan, IIT-Bombay19 SRES scenario quantification 42.htm

Anand Patwardhan, IIT-Bombay20 What do we do with SRES (in the V&A context)? Nothing Use / adapt the storylines – to what extent can we make them relevant at local / regional level? Use driver values for particular scenarios at national level to bound / constrain local drivers Aggregate / upscale driver values for local scenarios to check consistency with SRES scenario group

Anand Patwardhan, IIT-Bombay21 Final points Primary objective of SRES exercise was to produce emissions of greenhouse gases as the output, not changes in exposure units SRES scenarios are intended to exclude catastrophic futures The SRES scenarios are not scenarios of the evolution of the coupled system: They specifically exclude climate change policies (although they purport to include the effect of non- climate policies) Similarly, the scenarios exclude the possible feedback from the climate system on the biosphere You can check the scenarios themselves (and much more) at CIESIN: