When we think about traveling, one of the first decisions we make is how we are going to get around. Will we do it walking, with a bicycle, by public or private transport? The decision, if we have multiple options, will depend mainly on the conditions and needs of our trip, rather than whether one vehicle is better than the other.
Similarly, the selection of which methodology to use for a climate risk analysis in an adaptation planning process will depend on the objective of the assessment, its scope, the sector it is aimed at, and the needs of the process itself.
Today, we face one of the most pressing challenges of our era: climate change. The risks associated with climate are increasingly evident and their impact is being felt on a global, national and local scale. The need to identify, understand and estimate these risks is key to managing them.
What are climate risks?
Climate threats are inherent to the earth’s existence, but they are also exacerbated by anthropogenic global warming. Risk arises from the coexistence between society and the natural environment. This coexistence, when out of balance, generates a space where populations and assets are exposed to climate threats, while social, economic, cultural and political factors generate conditions that make society vulnerable to their impacts. In this way, risk results from the dynamic interaction between threats, exposure and vulnerability.
The estimation of climate risks includes the assessment of threats from extreme weather events, changes in weather patterns, and sea level rise. To achieve this, climate models are used to predict possible scenarios, from floods to droughts. Additionally, the possible adverse consequences on ecological and human systems must be evaluated [1]. Climate risk analyses, therefore, allow us to identify threats associated with climate, the degree of exposure of the system and the vulnerability factors. This information is essential to anticipate, reduce and minimize adverse consequences.
How are climate risks estimated?
There are various approaches and methodologies to estimate climate risks. On the one hand, deterministic approaches make assumptions about the relationships between the factors that describe the risk, so that they “predict” system behavior given certain conditions. On the other hand, probabilistic approaches associate statistical probabilities to the behaviors of the system, presented at random and, therefore, have an associated degree of uncertainty.
| Deterministic | Probabilistic | Qualitative |
| a. Global Circulation Models (GCM) b. Development of Climate Scenarios c. Historical Data Analysis d. Hydrological model e. Vulnerability f. AssessmentSocioeconomic impact analysis g. Climate Risk Maps | a. Montecarlo analysis b. Bayesian Risk Analysis c. Advanced Statistical Models d. Re e. Cadenas de Markov f. Simulaciones Estocásticas g. Modelos de Eventos Extremos h. Funciones de Distribución Acumulativa (FDA) i. Enfoques de Incertidumbre Paramétrica | a. Investigación participativaMapeo b. participativo Técnicas de c. valoración cualitativa |
In the deterministic approach, climate models such as Global Circulation (GCM) and Regional Models (RCM) are used to predict climate patterns at a global or regional level. Historical data analysis, which analyzes past climate records to project possible future risks, and Climate Scenario Analysis, which represents different possible trajectories of climate change, are also used.
Complementarily, the vulnerability assessment examines the susceptibility of natural and human systems to climate changes, while the development of socioeconomic scenarios makes it possible to evaluate how climate changes will affect specific communities, economies and sectors. Hydrological models are particularly useful for predicting behavior in watersheds under changes in variables (for example, precipitation). Finally, climate risk maps help visualize areas exposed to extreme weather events.
The probabilistic approach can help understand the probability of occurrence of extreme events and their possible impacts. Some of the methodologies used in risk analysis are the Monte Carlo Analysis, which uses computer simulations to evaluate possible climate scenarios and their consequences. Bayesian Risk Analysis applies Bayesian theory to update the probabilities of extreme weather events as new data is obtained. Advanced statistical models use probability distributions to represent the variability and uncertainty associated with extreme climate events.
In addition, other methodologies such as the return period, Markov chains, stochastic simulations, extreme event models and cumulative distribution functions are methodological alternatives to understand the probability and magnitude of extreme climate events. However, it is important to consider uncertainty in climate models and evaluate how it affects climate risk projections.
The application of these probabilistic methodologies improves the ability of researchers and decision makers to understand and quantify climate risks, considering the variability and uncertainty associated with climate change.
Often, quantitative information does not exist or is not accessible and, in other cases, it is not possible to establish a direct link between climate threats and their impacts. For this reason, qualitative alternatives are frequently used, such as participatory research, participatory mapping or qualitative assessment techniques. This participatory approach involves multiple actors in climate risk assessments and integrates local knowledge and experiences, improving the understanding and effectiveness of adaptation measures.
Which is the best methodology?
Determining the “best” methodology for climate risk assessment becomes a balancing exercise between various factors. The intrinsic complexity of climate change demands integrated approaches that address the interconnectedness of climatic, social, economic, cultural, political and regulatory factors, just to name a few.
The methodologies presented, some of the most common, offer valuable tools to describe the relationships between the factors that make up the risk, understand the probability and magnitude of extreme climate events, and evaluate their impact on communities and ecosystems. However, there is no single methodology that can comprehensively address the diversity of challenges associated with climate risks.
The choice and combination between these methodologies should be guided by the specific nature of the analysis, the resources available and the objectives pursued. Each approach has advantages and limitations, and will be more relevant in one case or another. Complementarity between approaches can enrich assessments, providing a more robust understanding of risks.
Ultimately, the search for the optimal methodology must go hand in hand with an adaptive and flexible approach, capable of evolving as our understanding of climate change and its impacts develops. The task is urgent, but we can build solid strategies to understand and manage the risks generated by climate change.
With special thanks to Raquel Gómez, María Teresa Abogado and Angela Prías, adaptation to climate change specialists.
[1] ‘Reisinger, Andy, Mark Howden, Carolina Vera, et al. (2020) The Concept of Risk in the IPCC Sixth Assessment Report: A Summary of Cross-Working Group Discussions. Intergovernmental Panel on Climate Change, Geneva, Switzerland. pp15. Consultado 18 Enero 2024 de https://www.ipcc.ch/site/assets/uploads/2021/02/Risk-guidance-FINAL_15Feb2021.pdf
