31.8. Carter

Keynote Presentations from the 1st ALTER-Net Summer School, Peyresq 27 August - 8 September 2006

Abstract

Scenarios of global change

The past centuries have witnessed a rapid increase in human population as a result of economic development and the successful exploitation of natural resources. Human activities have affected the environment through pollution and degradation of the basic "commons": air, water and soil. This has led to environmental problems such as acid rain, climate change, stratospheric ozone depletion and soil erosion. These changes are termed "global changes", because they affect all areas of the globe and because they touch upon all aspects of the relationship between human development and environmental change.

Europe has also experienced widespread global changes, a large portion of which are anthropogenic in origin. In order to anticipate global changes during the coming decades, and to prepare for their likely impacts on ecosystems and society, it is necessary to project current trends into the future. However, there are large uncertainties associated with estimates of human influence on complex natural systems, and it is impossible to predict the future with any confidence. Instead, it is customary to construct "scenarios". A scenario can be defined as "a coherent, internally consistent and plausible description of a possible future state of the world" (IPCC, 1994).

This lecture will introduce students to the concept of scenarios, contrasting descriptive and normative scenarios, emphasising the role of the base case scenario, and illustrating alternative approaches to scenario development:

• Qualitative scenarios
• Incremental scenarios for sensitivity testing
• Analogue scenarios
• Model-based scenarios
• Scenarios based on expert judgement
• Composite scenarios

Global change scenarios are often selected to shed light on key uncertainties in projections, though some studies may adopt other selection criteria (e.g. choosing the "best estimate" or "worst case" scenario). Scenarios can cover a wide range of issues, including:

• Socio-economic factors
• Land use and land cover
• Atmospheric composition
• Water quality
• Climate
• Sea level

Examples of each of these scenario types will be presented and students will be encouraged to participate in a scenario building exercise of their own as part of the group work following the lecture.

Questionnaire

A questionnaire (pdf: 300KB) has been handed out to the participants and the results (pdf: 300KB) have been shown and discussed already in Peyresq.

Recommended background literature on this presentation:

• Alcamo J (2001) Scenarios as tools for international environmental assessments. Environmental issue report No 24, Experts' corner report Prospects and Scenarios No 5, European Environment Agency (pdf: 400KB), Luxembourg, pp 31.
  
• Alcamo J, Leemans R, Kreileman E (eds.) (1998) Global change scenarios of the 21st century. Results from the IMAGE 2.1 Model. Pergamon, London, 296 pp.
• Alcamo J, van Vuuren D, Ringler C, Alder J, Bennett E, Lodge D, Masui T, Morita T, Rosegrant M, Sala O, Schulze K, Zurek M (2005) Methodology for developing the MA scenarios. In: Ecosystems and Human Well-being: Scenarios. Findings of the Scenarios Working Group, Millennium Ecosystem Assessment, Carpenter SR, Pingali PL, Bennett EM, Zurek MB (Eds) Island Press, 145-172. Chapter 6: http://www.maweb.org/en/Products.Global.Scenarios
• Carter TR, La Rovere EL, Jones RN, Leemans R, Mearns LO, Nakicenovic N, Pittock AB, Semenov SM, Skea J (2001) Developing and applying scenarios. In: McCarthy JJ, et al. (eds), Climate change (2001) Impacts, adaptation, and vulnerability. Contribution of Working Group II to the Third Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge and New York, pp 145-190. http://www.grida.no/climate/ipcc_tar/
• Lebel L, Thongbai P, Kok K, Agard JBR, Bennett E, Biggs R, Ferreira M, Filer C, Gokhale Y, Mala W, Rumsey C, Velarde SJ, Zurek M (2005) Sub-global scenarios. In: Ecosystems and Human Well-being: Multiscale Assessments, Volume 4, Millennium Ecosystem Assessment, Carpenter SR, Pingali PL, Bennett EM, Zurek MB (Eds) Island Press, 229-259. Chapter 10: http://www.maweb.org/en/Products.Global.Multiscale.
• Nakicenovic N, Alcamo J, Davis G, de Vries B, Fenhann J, Gaffin S, Gregory K, Grübler A, Jung TY, Kram T, La Rovere EL, Michaelis L, Mori S, Morita T, Pepper W, Pitcher H, Price L, Raihi K, Roehrl A, Rogner H-H, Sankovski A, Schlesinger M, Shukla P, Smith S, Swart R, van Rooijen S, Victor N, Dadi Z (2000) Emissions scenarios. A Special Report of Working Group III of the Intergovernmental Panel on Climate Change. Cambridge University Press, 599 pp. http://www.ipcc.ch/pub/sres-e.pdf
• Parry M (ed.) (2000) Assessment of potential effects and adaptations for climate change in Europe: The Europe ACACIA Project, Jackson Environment Institute, University of East Anglia, Norwich, UK, 320 pp.
• Parry ML (2002) Scenarios for climate impact and adaptation assessment. Global Environmental Change 12: 149-153. doi:10.1016/S0959-3780(02)00038-9
• Raskin P, Banuri T, Gallopin G, Gutman, P, Hammond A, Kates R, Swart R (2002) Great transition: The promise and lure of the times ahead. SEI PoleStar Series Report no. 10, Global Scenario Group, Stockholm Environment Institute, Stockholm, 99 pp. http://www.tellus.org/seib/publications/Great_Transitions.pdf (1MB)
• Raskin P, Monks F, Ribeiro T, van Vuuren D, Zurek M (2005) Global scenarios in historical perspective. In: Ecosystems and Human Well-being: Scenarios. Findings of the Scenarios Working Group, Millennium Ecosystem Assessment, Carpenter SR, Pingali PL, Bennett EM, Zurek MB (Eds) Island Press, 35-44. Chapter 2:http://www.maweb.org/en/Products.Global.Scenarios.
• Rounsevell MDA, Reginster I, Araújo MB, Carter TR, Dendoncker N, Ewert F, House JI, Kankaanpää S, Leemans R, Metzger MJ, Schmit C, Smith P, Tuck G (2006) A coherent set of future land use change scenarios for Europe. Agriculture, Ecosystems & Environment, 114 57–68. http://dx.doi.org/10.1016/j.agee.2005.11.027
• Schneider SH (2001) What is 'dangerous' climate change? Nature, 411, 17-19. doi: 10.1038/35075167
• Grübler A, Nakicenovic N (2001) Identifying dangers in an uncertain climate. Nature, 412, 15. doi: 10.1038/35083752