The use of scenarios in climate risk assessment#
A scenario is a strategic planning tool designed to explore “what-if” situations, helping us prepare for problems that might arise in the future. Scenarios can help to understand how external economic, environmental, social and/or political contexts may influence the risk in a region. In the context of the CLIMAAX project, scenarios relate to climate change and socio-economic development. Examples of scenario variables include rainfall and other aspects of the climate, demographic and socio-economic trends and changes, food consumption and prices.
In the context of Climate Risk Assessments (CRA), scenarios support local authorities in understanding how the future may unfold, making them essential for informed decision-making and effective planning. These pages aim to provide guidance for scenario development. Further and more detailed information is available in the list of background reading.
See also
Before you start » Technical choices
Why explore multiple scenarios?#
A good plan for regional development and management should not only address present risks and impacts, but should also prepare for risks that might arise in the future. Exploration of multiple scenarios can increase resilience as it helps to:
Map different futures. Mapping different future scenarios is important to understand possible climate risks (such as impacts of heatwaves, wildfires, floods, droughts) and the effect of different actions for climate adaptation and mitigation. Exploring multiple scenarios helps to formulate robust and flexible strategies that can adapt to changing climate conditions.
Guide adaptation actions. Insights gained from scenario analysis can guide adaptation actions. This includes implementing low-regret options that offer benefits regardless of how the future unfolds, as well as robust strategies that perform well across various conditions.
Prevent maladaptation. Exploring multiple climate and socio-economic scenarios helps prevent maladaptation by ensuring that actions are effective across a range of future conditions. It avoids under- or over-investing in solutions by identifying strategies that work in various scenarios.
Combining climate and socio-economic scenarios#
The choice of which scenario to prioritize in planning largely depends on the user’s needs and risk tolerance. High-risk scenarios – such as worst-case scenarios – may require more stringent and risk averse policies and preparations, while low-risk scenarios – such as best-case scenarios – offer a more optimistic but possibly less robust approach. Decision makers must balance the amount of risk they are willing to accept with the potential consequences, ensuring that their strategies align with their goals and resources. Scenario development should always aim to be as simple and transparent as possible while still adequately addressing the problems to be solved.
By systematically developing and analyzing multiple climate and socio-economic scenarios, we can better understand potential future risks and develop strategies that are robust across a range of possible futures. This approach enhances our ability to plan effectively, allocate resources wisely, and build resilience against the uncertainties of climate change.
Ideally, the analysis should be carried out for all the scenario combinations, and the selection of which strategy to use should be based on the evaluation of which is best able to cope with all possible future developments. In reality, most analyses are carried out for a limited number of scenarios. The climate risk management strategy that results from this is then analyzed in a ‘scenario analysis’ to test the strategy for its robustness and flexibility in other possible futures.
Background reading#
Buskop, F. E.; Sperna Weiland, F.; van den Hurk, B. (2024). Amplifying exploration of regional climate risks: Clustering future projections on regionally relevant impact drivers instead of emission scenarios. Environmental Research: Climate, 3(4), 045030. DOI: 10.1088/2752-5295/ad9f8f.
Ebi, Kristie L.; Kram, Tom; van Vuuren, Detlef P.; O’Neill, Brian C.; Kriegler, Elmar (2014): A New Toolkit for Developing Scenarios for Climate Change Research and Policy Analysis. In Environment: Science and Policy for Sustainable Development 56 (2), pp. 6–16. DOI: 10.1080/00139157.2014.881692.
Moss, Richard H.; Edmonds, Jae A.; Hibbard, Kathy A.; Manning, Martin R.; Rose, Steven K.; van Vuuren, Detlef P. et al. (2010): The next generation of scenarios for climate change research and assessment. In Nature 463 (7282), pp. 747–756. DOI: 10.1038/nature08823.
O’Neill, Brian C.; Kriegler, Elmar; Ebi, Kristie L.; Kemp-Benedict, Eric; Riahi, Keywan; Rothman, Dale S. et al. (2017): The roads ahead. Narratives for shared socioeconomic pathways describing world futures in the 21st century. In Global Environmental Change 42, pp. 169–180. DOI: 10.1016/j.gloenvcha.2015.01.004.
Riahi, Keywan; van Vuuren, Detlef P.; Kriegler, Elmar; Edmonds, Jae; O’Neill, Brian C.; Fujimori, Shinichiro et al. (2017). The Shared Socioeconomic Pathways and their energy, land use, and greenhouse gas emissions implications: An overview, Global Environmental Change, Volume 42, 2017, Pages 153-168, ISSN 0959-3780, DOI: 10.1016/j.gloenvcha.2016.05.009.
Reimann, L., Vafeidis, A. T., & Honsel, L. E. (2023). Population development as a driver of coastal risk: Current trends and future pathways. Cambridge Prisms: Coastal Futures, 1, e14. DOI: 10.1017/cft.2023.3.
Shepherd, T.G., Boyd, E., Calel, R.A., Chapman, S.C., Dessai, S., Dima-West, I.M., et al., 2018. Storylines: an alternative approach to representing uncertainty in physical aspects of climate change. Clim. Change 151, 555–571. DOI: 10.1007/s10584-018-2317-9.
van Vuuren, Detlef P.; Edmonds, Jae; Kainuma, Mikiko; Riahi, Keywan; Thomson, Allison; Hibbard, Kathy et al. (2011): The representative concentration pathways. An overview. In Climatic Change 109 (1-2), pp. 5–31. DOI: 10.1007/s10584-011-0148-z.
van Vuuren, Detlef P.; Kriegler, Elmar; O’Neill, Brian C.; Ebi, Kristie L.; Riahi, Keywan; Carter, Timothy R. et al. (2014): A new scenario framework for Climate Change Research. Scenario matrix architecture. In Climatic Change 122 (3), pp. 373–386. DOI: 10.1007/s10584-013-0906-1.