Climate risk scenarios guidance

Climate risk scenarios guidance#

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Climate risk scenarios are a way to analyse how potential climate, and socio-economic developments determine future climate impacts in the region. By going through multiple combinations of climate and socio-economic scenarios, we can find favourable and unfavourable risk conditions which can help to steer adaptation policies.

Understanding Scenarios#

What is a scenario?: A scenario is a strategic planning tool designed to explore “what-if” situations, helping us navigate uncertainty by envisioning different future outcomes. It allows individuals, businesses, and policymakers to assess how various factors or decisions might unfold, revealing potential consequences. By highlighting vulnerabilities and opportunities, scenarios provide a clearer understanding of how complex situations may evolve. Climate plans and strategies should not only address present risks but also prepare for risks that may emerge in the future.
Importance in Climate Risk Assessments: 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 in an uncertain world. By combining climate and socio-economic trends, scenarios enable the development of resilient policies and strategies that can adapt to a range of possible futures, ensuring preparedness for upcoming challenges or opportunities.

The Importance of Exploring Multiple Scenarios#

Mapping Different Futures: Exploring multiple climate scenarios is crucial because future climate risks are uncertain and influenced by factors such as emission levels, the Earth’s complex response to those emissions, and societal changes over time. These uncertainties make it impossible to predict a single outcome, so considering a range of potential futures is essential for effective risk assessment.
Exploring a Range of Plausible Outcomes: By analysing various scenarios, we can identify different risk profiles and gain a clearer understanding of how hazards like flooding, heatwaves, or sea-level rise may impact different regions. Understanding what could happen helps us recognize favourable and unfavourable conditions, enabling more informed planning to achieve a desirable future or to prepare for a range of potential futures.
Prioritizing Scenarios in Planning: The choice of which scenario to prioritize in planning largely depends on the user’s needs and risk tolerance. High-risk scenarios may require more stringent policies and preparations, while low-risk scenarios offer a more optimistic approach. Ultimately, users 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.
Guiding Adaptation Actions: Insights gained from scenario analysis and their resulting effects on regional risk can guide adaptation actions that focus on resilience. 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. Additionally, pursuing adaptation strategies that can evolve over time ensures communities can respond to unforeseen challenges.
Preventing 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, reducing wasted resources.

Scenarios development#

Creating climate scenarios is essential for preparing for future risks, but how do we develop such scenarios? This section provides theoretical guidance on what to consider when starting the process. These insights can help you tailor climate risk scenarios to your region, identify vulnerabilities, and make better-informed decisions.

Hint

Before, one starts out with finding out if relevant scenarios that have already been developed. These can be scenarios leading in local legislation or that relevant stakeholders use.

Characteristics of Effective Scenarios#

What makes a scenario a useful scenario to take along in the CRA? Here we provide a list of characteristics to keep in mind when creating scenarios.

Relevant: Focus on the specific issue or question you’re trying to understand. Provide information that supports targeted decision-making and future planning, rather than being too general or off-topic.
Plausible: Ensure the scenario is realistic and credible, based on facts or logical assumptions. It should represent something that could actually happen, even if it’s a projection about the future.
Consistent: Maintain coherence where all parts fit together logically. Facts and assumptions should align without contradictions, ensuring the scenario makes sense as a whole.
Distinctive: Create scenarios that are unique compared to others. This allows exploration of different possibilities or outcomes, helping you consider various futures rather than repeating the same ideas.

Climate scenarios#

To analyse climate impacts multiple approaches can be taken. Firstly, we can learn a lot from historical events and how these might impact society if they occur again in a different form. Secondly, we can analyse climate projections to find how future climate might change

Learning from past events: Even before diving into future climates we can already learn from events that have already occurred. Because of their ability to represent small scale process such as intense rainfall events which are not available in current climate models, we can leverage them for ‘what if’ scenarios.
Displacement of Events: One way to learn from events is to examine historical events that occurred in other regions but could happen locally due to changing climate patterns or just by randomness of where the event actually occurred.
Intensification of Events: Data from historical events can be modified to replicate what would happen in a warmer world. One could intensify rainfall events, intensify hurricanes, or droughts.
Consecutive Events: A useful exercise can be to consider the impact of multiple events occurring in succession, such as back-to-back wind storms and flooding or simultaneously such as multiple wildfires in different locations. These can help to identify bottlenecks.
Climate projections: Climate projections are estimates of future climate conditions coming from global climate models (GCMs) based on a range of emission scenarios.
Climate uncertainty: Climate projections cannot provide a simple answer to what will happen. Many models, emissions scenarios and model runs result in many different projections. Disagreement exist due to uncertainties in future emission, model uncertainty (how models represent physical processes) and internal variability (randomness of the weather).
Emissions as guiding scenarios: Often global emissions are used to aggregate model projections in regions. The idea is to obtain a climate change signal that is caused by emissions. On large scales such as global or continental such aggregation can lead to clear signals. Unfortunately, for local analysis climate patterns in projections are mainly determined by internal variability and climate model uncertainty. This result in unclear climate signals across emission scenarios, and does not help to explore a range of potential future impacts.
Key climate variables driving impact: Instead of relying on emission scenarios for future projections, one can also focus on basing scenarios on climate variables that drive impact in the region. This can lead to scenarios leading to a better exploration of future impact than emission based scenarios can.

Socioeconomic scenarios#

While climate change influences hazards like floods, heatwaves, and storms, societal factors significantly shape overall risk. Urban development, infrastructure design, and land-use decisions can either amplify or reduce climate-related risks. Poorly planned urban areas may suffer more from extreme weather, while well-designed cities with resilient infrastructure can better withstand these events.

Shared Socioeconomic Pathways (SSPs): SSPs help assess how different social and economic futures could alter climate impacts. Are we going to be in a world of sustainable development, fossil-fuelled growth or something entirely different? Based on assumptions associated with these narratives population, urbanisation and GDP datasets have been created together with many spin off variables that try to capture what the future might hold. Many studies have information on national scale and some even on the local level.
Exploring Future Regional Development: Understanding how a region might develop in the future is crucial for assessing how societal choices may increase or decrease climate risks. Factors like population growth, economic policies, and building practices can make some areas more vulnerable, while sustainable planning and adaptation measures can reduce risk. By considering these societal drivers alongside climate projections, we can create more effective strategies to minimize future harm.

Combining scenarios#

Once you have defined the most important drivers of risk and identified their potential changes, these drivers can be combined in a scenario matrix to account for combination effects. The matrix is a versatile tool for examining how different combinations of these drivers could influence risk levels. Here we provide a few simple examples:

The scenario matrix helps understanding not only isolated impacts but also how combinations of risk drivers might interact, compound, or even mitigate each other, thereby supporting robust decision-making and adaptation planning across various plausible futures.

Conclusion#

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.