Flood risk: strengthening resilience of coastal communities through improved forecasting and projection

IOC/UNESCO

Flood risk: strengthening resilience of coastal communities through improved forecasting and projection

Flood risk: strengthening resilience of coastal communities through improved forecasting and projection 667 533 Ocean Decade

With over 40% of the global population living within 100km of the coast – a trend on the rise – and increasingly exposed to climate risks, urgent and innovative adaptation solutions are needed to face the many and diverse challenges to the communities and the ecosystems in these areas. Through a joint call for fellows launched by the AXA Research Fund and UNESCO’s Intergovernmental Oceanographic Commission as part of the Ocean Decade, seven ground-breaking postdoctoral research projects have been endorsed as part of the Ocean Decade and will strengthen science-based interventions for coastal livelihood preservation and resilience.

One of the seven selected fellows of the AXA – IOC/UNESCO joint call, Dr. Andrea Ficchì is a hydrologist, data scientist and environmental engineer specializing in flood forecasting, based at the Politecnico di Milano, Italy, in the Environmental Intelligence Lab led by Professor Andrea Castelletti. His research project, launched in November 2022, seeks to improve compound flood forecasting and understanding of uncertainties in future projections.

“My work deals with forecast evaluation, machine learning, forecast-based action and humanitarian applications, among other aspects,” says Andrea. “The goal is to advance the understanding of flood forecast predictability and flood drivers, and consequently improve resilience to natural hazards, in particular in communities in sub-Saharan Africa.”

More than 600 million people around the world live less than 10 meters above mean sea level;[1] at the same time, climate change is accelerating sea-level rise and making coastal flooding more severe and destructive. Compound riverine and coastal flooding endangers the lives of millions of people in coastal areas and can wash away their habitats, destroy their livelihoods and damage infrastructures.

Andrea’s project will have a particular focus on Mozambique. Situated in Southern Africa, it is one of the world’s most natural disaster-prone countries, with a high risk of compound floods caused by tropical cyclones.

“Economic damages from global coastal floods and storm surges currently range between US$10 billion and US$40 billion a year. In the absence of solid adaptation measures, previous studies agree that these damages are expected to increase significantly, despite a wide range of uncertainties;[2] considering major coastal cities only, damages are expected to rise to more than US$1 trillion annually by 2050,”[3] he alerts.

In Mozambique, the government recently concluded that, on average, the country is affected by a tropical cyclone or flood event every two years.[4] In 2019, cyclones Idai and Kenneth caused more than 700 fatalities, displaced some 420,000 and affected more than two million people. A case study led by the World Meteorological Organization determined that the loss of life and damage could have been reduced with better flood forecasting and improved warnings.[5]

Faced with the inevitability of rising sea levels and episodic flooding events, local and national coastal authorities around the world have historically pursued two possible courses of action.

‘Soft-path’ measures, such as early warning and early action systems, real-time emergency management, insurance and disaster financial risk hedging mechanisms, are examples of short-term solutions to increase coastal communities’ resilience to climate change.

On the other hand, long-term solutions typically rely on ‘hard-path’ measures. These consist of coastal protection structures – barriers, seawalls and revetments – the reinforcement of houses and infrastructures, as well as the implementation of nature-based solutions, such as land-use planning to reduce impervious surfaces and restore coastal ecosystems. However, as sea levels continue to rise, so will the cost to maintain and improve those defenses, and so will the cost of failure.

“Hard infrastructures and nature-based solutions, though effective, face practical challenges,” says Andrea. “They necessitate huge and risky investments while being subject to significant uncertainty in terms of climate risk, government financial capacity, infrastructure investment decisions and local land-use regulation.”

Such challenges can be overcome by modulating investments over time, and integrating hard-path measures with soft-path solutions as hedging mechanisms, using decision analytics methods and climate data, to identify robust and optimal pathways.

During his two-year AXA Research Fund fellowship, Andrea will employ machine learning to better predict compound flood risk and identify high-risk areas. He will base his work on climate services; in other words, climate information and products generated to inform and assist in decision-making processes related to climate risk management.[6]

“Climate services are part of a complex climate-environment-society system in which climate is one of the many factors to be considered. Still, they remain the basis of any adaptation strategy,” he states. “In my case, I will use flood risk forecasts and projections to help coastal communities increase their resilience in the short and long term.”

Resilience is key. Andrea’s research will help tackle Ocean Decade Challenge 6, which aims to enhance multi-hazard early warning services for all geophysical, ecological, biological, weather, climate and anthropogenic related ocean and coastal hazards, and mainstream community preparedness and resilience.[7]

Nevertheless, many issues hinder the uptake of current climate services for policy and decision-making. These include forecasts and projections uncertainties, limited skill level of forecasts, lack of understanding of the accuracy associated with existing models and data, institutional barriers, as well as local technical/capacity limitations.

Thanks to a multi-source flood extent and impact database, Andrea will assess the skill level of current state-of-the-art predictions and guide the machine learning algorithms to enhance them. He will demonstrate the potential value of existing climate services and of the improved predictions by focusing on their capacity to support humanitarian emergency management and weather-based insurance.

“The research will also consider the needs and preferences of local stakeholders and users of climate services to improve compound flood forecasting,” details Andrea. “Through tailored predictions, coastal communities will be able to mitigate and better manage natural disaster risks and, in turn, become more resilient.”

Listen to Andrea’s full interview here:


For more details on Andrea’s project, visit his Action page on the Ocean Decade website and his project page on the AXA Research Fund website.

For more details on all the winning projects, visit the AXA Postdoctoral Fellows page.

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About IOC/UNESCO:

The Intergovernmental Oceanographic Commission of UNESCO (IOC/UNESCO) promotes international cooperation in marine sciences to improve management of the ocean, coasts and marine resources. The IOC enables its 150 Member States to work together by coordinating programmes in capacity development, ocean observations and services, ocean science and tsunami warning. The work of the IOC contributes to the mission of UNESCO to promote the advancement of science and its applications to develop knowledge and capacity, key to economic and social progress, the basis of peace and sustainable development.

About the Ocean Decade:

Proclaimed in 2017 by the United Nations General Assembly, the UN Decade of Ocean Science for Sustainable Development (2021-2030) (‘the Ocean Decade’) seeks to stimulate ocean science and knowledge generation to reverse the decline of the state of the ocean system and catalyse new opportunities for sustainable development of this massive marine ecosystem. The vision of the Ocean Decade is ‘the science we need for the ocean we want’. The Ocean Decade provides a convening framework for scientists and stakeholders from diverse sectors to develop the scientific knowledge and the partnerships needed to accelerate and harness advances in ocean science to achieve a better understanding of the ocean system, and deliver science-based solutions to achieve the 2030 Agenda. The UN General Assembly mandated UNESCO’s Intergovernmental Oceanographic Commission (IOC/UNESCO) to coordinate the preparations and implementation of the Decade.

About the AXA Research Fund:

The AXA Research Fund was launched in 2008 to address the most important issues facing our planet. Its mission is to support scientific research in key areas related to risk and to help inform science-based decision-making in both the public and private sectors. Since its launch, the AXA Research Fund has committed a total of €250M to scientific funding and supported nearly 700 research projects in the areas of health, climate and environment, and socio-economics.

[1] UNESCO-IOC. 2022. UNESCO Ocean Programmes. Paris, UNESCO.

[2] Hinkel et al. 2014. Coastal flood damage and adaptation costs under 21st century sea-level rise. Proceedings of the National Academy of Sciences, 111(9), 3292–3297. https://doi.org/10.1073/pnas.1222469111

[3] Hallegatte, S., Green, C., Nicholls, R. et al. 2013. Future flood losses in major coastal cities. Nature Climate Change 3, 802–806. https://doi.org/10.1038/nclimate1979

[4] Government of Mozambique. 2021. Update of the First Nationally Determined Contribution to the United Nations Framework Convention on Climate Change.

[5] World Meteorological Organization. 2020. 2020 State of Climate Services: Risk Information and Early Warning Systems. Geneva, World Meteorological Organization.

[6] https://www.wfp.org/climate-services

[7] https://oceandecade.org/challenges/

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