As climate change causes sea levels to rise to unprecedented levels, governments and citizens in vulnerable countries are looking at innovative ways to forecast, prevent, adapt to and insure against flooding.
Floods across West and Central Africa in the last two weeks have displaced more than 3.4m people, according to the UN Refugee Agency, punctuated by Nigeria’s worst floods in a decade, which have killed hundreds and affected 2.8m people.
Extreme flooding has killed more than 1300 people in Pakistan since June and is now threatening to trigger a food crisis.
Flooding is set to become more common going forwards. A UN report released last week found that the planet is on track to warm by between 2.1°C and 2.9°C above pre-industrial levels by the end of the century despite government action to fight climate change.
Vulnerable coastal mega-cities
With the world unable to address climate change in the short to medium term, countries must urgently find solutions to mitigate the devastating effects of extreme flooding.
More than 1.8bn people – roughly 23% of the world’s population – are exposed to high flood risk. Over 1.2bn of these are located in South and East Asia, including 395m in China and 390m in India. Of the 170m people facing both high flood risk and extreme poverty, 44% reside in sub-Saharan Africa.
These large numbers reflect the concurrent rise of sea levels and urbanisation, which render those living in coastal mega-cities among the most vulnerable.
Traditional engineering solutions like flood walls and embankments help but can be insufficient if drains or floodplains are non-existent, ageing or blocked. In Nigeria, for example, government officials say structures built along drains have contributed to the severity of the flooding in Lagos.
One approach is so-called sponge cities, which seek to develop and work with nature to absorb, clean and use excess water during extreme floods. For instance, the Chinese port city of Ningbo transformed 3 km of previously developed land that had fallen into disuse into an eco-corridor and public park.
Creating more sustainable ecosystems further out to sea is another approach to weather the surge of water during heavy storms. Some Southern and East African nations are seeking to build a so-called Great Blue Wall to protect coastal and marine areas running from Somalia to South Africa in the Indian Ocean.
Technology is playing a profound role in helping countries predict floods and forewarn residents of danger.
With 20% of the country estimated to be at risk for flooding, Malaysia has become a global leader in deploying forecasting and monitoring technologies.
By the end of 2022 Malaysia’s Department of Irrigation and Drainage (DID) will roll out its National Flood Forecasting and Warning System, which was developed with UK engineering consultancy company HR Wallingford.
The system collects data from 700 observation gauges spread throughout the country – often placed in challenging terrain – to create simulations and models that can better prepare residents and officials.
Drones are increasingly being employed to record precise image data that planners can use to prevent and forecast floods and assess damage afterwards.
The Malaysian Space Agency uses drones and two satellites – with a third planned to be launched in 2025 – to identify areas that are prone to flooding before the rainy season starts. The agency’s integrated disaster-management system and the satellite image-based information and logistics system known as eBanjir directly assist DID in its flood management initiatives.
Brazil is similarly leveraging data through its Waterproofing Data mobile phone app, developed locally in March 2022 in collaboration with researchers from Germany and the UK.
The app allows community members to become citizen scientists by recording rainfall and flood impact assessments that can be used to plan for or prevent serious flooding. The app is currently in use across 20 municipalities, and the research team behind the platform is seeking to deploy it in other countries around the world.
The use of higher-quality and larger volumes of data means that artificial intelligence can help forecast when floods might occur, enabling the construction of more targeted flood-resistant infrastructure. For instance, researchers at Stanford University in the US are using machine learning to track atmospheric patterns and predict when precipitation will trigger flooding.
In addition to uprooting people, flooding imperils food security in the short term by destroying infrastructure, cropland and livestock, and damaging water resources and sanitation in the months that follow.
To counter this, planting more resilient crops could help smallholder farmers who have lost an estimated $21bn in agricultural products and livestock to flooding over the past decade, second only to droughts.
Researchers are using genetic tools to breed the gene responsible for flood tolerance called Sub1. Use of the resulting flood-resistant rice, which yielded 60% more rice than standard varieties in a controlled experiment, could go a long way towards reducing the 4m tonnes of rice that are lost to floods each year.
Over the past decade, farmers in the Philippines have widely adopted Submarino rice, a strand that does not die when it is submerged under water for up to 14 days.
Other subsistence farmers are turning to an old practice of using floating farms to secure their crop yields amidst rising sea levels.
More than 6000 farmers in the deltas of south-western Bangladesh – which are already underwater for eight to 10 months of the year, up from five months a year roughly 200 years ago – are using the practice to grow fruits and vegetables on rafts made from invasive hyacinths.
Farmers in Mexico also revived the use of chinampas (farm islands) – long, narrow strips of land over shallow lakes near Mexico City that are anchored to the lake floor with a native willow tree – to meet agricultural demand when traditional markets closed during the Covid-19 pandemic.
Developed by the Aztecs more than 700 years ago, chinampas are highly fertile growing fields that accommodate a range of production, from fruits and vegetables to eggs and honey. They have the added benefit of meeting their water needs directly from the lakes themselves.
By Oxford Business Group
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