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| Children in Bangladesh go to their floating school - not all solutions to flooding are high tech or hugely expensive |
Whether we like it or not, whether we believe in it or not, Climate Change is already here. Whole new words such as 'heat dome,' 'rain bomb,' 'megafire' and "microburst' have entered our lexicon in recent times and, while we should continue to work very hard on reducing our emissions, we should also be preparing for worst case scenarios, because even our best efforts look like falling short of the mark and even if we were to stop pumping CO2 into the atmosphere right this minute, the inbuilt momentum of the emissions already there would mean that it would take many decades before our climate returned to normal, if it ever did.
I have already written about some of the things individuals can do to protect themselves against extreme heat and climate related disasters, but now I want to look at some of the large -scale ways in which governments are tackling the risks which they are most likely to encounter.
Much of this information has come from an important but largely unsung Climate Adaptation Conference held in New Zealand in June and The Climate Adaptation Platform website.
It builds on the Sendai Framework for Disaster Risk Reduction 2015–2030 -a global agreement adopted by UN member states to guide efforts in reducing disaster risk and building resilience.
The Aims of the Sendai Protocol include the following:
1. Reduce global disaster mortality
2. Reduce the number of affected people
3. Reduce economic loss
4. Reduce damage to critical infrastructure and disruption of basic services
5. Increase national and local disaster risk reduction strategies
6. Enhance international cooperation
7. Increase access to multi-hazard early warning systems and disaster risk information
Key Areas of Concern
1. Coastal Inundation, Flooding, Storm Surges and Sea Level Rise
2. Heatwaves, Heat Domes, Megafires
3. Rain Bombs and Cyclones, Water Stress, Impact on Agriculture
4. Rising Ocean Temperatures, Coral Bleaching, Algal Blooms, Ocean Currents
5. Melting Ice Caps , Glaciers and Permafrost
6. Impact on Infrastructure
Of necessity, I’ll discuss each of these in turn, but be aware that many issues are interrelated. For example, what we do about flooding – e.g. restoring wetlands, may provide greater water availability and reduce ambient temperatures in urban areas at the same time, or for example, rapid melting of ice caps may mean flooding on the one hand, but less water availability at other times of the year.
Nor are measures mutually exclusive, with many countries employing multiple strategies. See Singapore for example, which is using both sea barriers and land reclamation across 70% of its coastline.
1. Coastal Inundation, Flooding, Storm Surges and Sea Level Rise
A 2021 study using LIDAR data found that 410 million people currently live on land less than 2 meters above sea level, with up to 570 cities being affected by the end of the 21st Century. Among the most vulnerable are Amsterdam and Venice in Europe, Asian cities such as Shanghai, Bangkok and Jakarta, Lagos in Nigeria, US cities such as New Orleans and Miami, and whole countries such as Bangladesh, Kiribati and the Maldives.
Responses fall broadly into four main categories - the erection of physical barriers, nature - based solutions to manage water flow, physical relocation and adaptation to rising water levels. Some examples of each follow.
Flood Barriers and Sea Walls
Venice - another very vulnerable city, is also relying on a system of 78 sea gates which block high tides from entering the Venetian Lagoon. While they have successfully prevented flooding of important landmarks, its MOSE (Modulo Sperimentale Elettromeccanico) system faces future challenges as sea levels continue to rise and storm surges become more frequent. MOSE has already had to be deployed 30 times in 2024 -25 compared to less than 20 times in earlier years.
There are now fears that it may have to operate up to 260 times a year if global warming continues and that this would lead to detrimental effects on the lagoon ecosystem, which has already been experiencing fish kills. MOSE has bought Venice time, but alternative solutions are also being investigated such as relocating some of the population, elevating buildings and wetland restoration.
New Orleans has been working on improving its flood defences since Hurricane Katrina flooded 80% of the city in 2005. This includes building huge dam barriers, a series of reinforced levees and flood walls for 560 km around the city as well as water parks and wetlands.
Nature - Based Solutions
Mangroves have been called "The silent climate warriors" because they not only sequester four to ten times more carbon than conventional forests, but protect coastlines, buffer storms, provide habitat for fish and sustain coastal communities.
It's a shame that people didn't know this when they cut so many of them down, especially in the 1980s and 1990s -to make way for shrimp farms in Thailand for example, to provide firewood and timber as in Kenya, for palm oil plantations, tourist developments and so forth. Now the race is on to replace them, with many countries from Mombassa to India, Sri Lanka and Thailand, Indonesia, Malaysia and parts of the Americas working hard to restore them. Ironically, abandoned shrimp ponds in Thailand are proving to be one of the most effective environments for replanting.
- Bangladesh also faces difficulties with two thirds of the country being less than 5 m above sea level. Impacts such as salinity intrusion, land erosion, water -logging and the emergence of char islands are already affecting agriculture and livelihoods. It too is planting mangroves to intercept storm surges and prevent erosion. Communities are also involved in embankment building, but one of its most innovative efforts is the building of floating schools.
In flood season, these solar-powered boats transform into classrooms, libraries, and clinics and this model is now being applied to climate-resilient floating farms and training centres. The floating farms are essentially hydroponic gardens on rafts to ensure food security.
Wetlands
- In the USA, San Francisco Bay aims to restore 100,000 acres of tidal marshlands to reduce erosion and the impact of storm surges. It has already purchased and or restored 78,000 acres.
North Carolina is stabilising its dunes with native grasses. Chile is using wetland restoration to prevent flood damage and saltwater intrusion. This benefits agriculture, property values and tourism. In the BiobÃo –Rocuant –Andalién Region restoration of 579 hectares of degraded wetlands is underway to buffer against flooding, saline intrusion, and biodiversity loss.
These wetlands act as natural sponges, increasing water retention and reducing flood damage. They also improve drinking water quality and soil health, not to mention improving the lives of residents by creating employment and recreational opportunities.
- Created green roofs on thousands of buildings. These use plants to capture rainwater
- Established wetlands along the Huangpu River
- Replaced asphalt footpaths with permeable pavements
Benefits include reduced flooding, better air quality, and increased urban biodiversity, creation of public spaces – parks, riverbank cycleways and the like, which filter pollutants before they reach waterways and recharge aquifers as well as creating more green space and promoting urban cooling.
Although China has taken to ‘sponge cities’ in a big way, it was in fact Denmark which started the ball rolling. After a 2011 'once -in -a millennium flood' - how often have we heard that lately? - which affected roads, hospitals, businesses and homes, it brought together city planners, architects and landscape designers to redesign Copenhagen to better withstand such events.
The result was a series of underground and above -ground features including a university square which doubles as bicycle storage but could also retain and filter storm water for later release. Even skate parks could be used in this manner and these were supplemented with bioswales – grassed depressions between streets, pocket gardens with water absorbing plants, green roofs and permeable footpaths. Although the main purpose was to reduce flood risks, the system now also provides additional water in times of drought.
For more on creating sponge cities, click here
Other cities applying the same principles include:
- Bangkok – Facing flooding due to both land subsidence and climate change, Bangkok could be below sea level as early as 2030 by worst estimates. The city has built an 11-acre park which can hold up to 1 million gallons of water to prevent flooding during its summer rainy season.
Rotterdam – Based on a pilot study in 2008 -2009 Rotterdam has created water plazas that double as public squares and flood reservoirs
Philadelphia – With flooding resulting in sewerage overflows, the city’s new “Green City, Clean Waters” program is replacing outdated sewers with green infrastructure. A 25 -year project, it too is about capturing stormwater close to the source with the use of large-scale tree planting, rain gardens, porous paving and the like, the bonus being not only flood control but an additional 500 acres of public green space.
Going with the Flow
- Oceanix (Butan) South Korea is a prototype floating city for 5,000 people with modular neighbourhoods, designed to rise and fall with the tide. Though attractive in theory, takers are still few.
- The Maldives are only 1 metre above sea level and apart from raising one its main islands by adding more sand, it is also taking to the water. Its government is in the process of developing a ‘green’ modular floating city for 20,000 by 2027.
- In Vietnam elevated stilt housing in the Mekong Delta is being created to float with the rising flood waters, but adapted with local materials and community-led design.
Relocation and Managed Retreat
- In Fiji some 40 villages are being relocated over
the next 5-10 years.
- Low lying Pacific Islands like Tuvalu and Kiribati are at the front line of Climate Change. Kiribati has already made contingency plans by buying up 50,000 ha in Fiji to relocate its population of 113,000 when it becomes unavoidable. Tuvalu is still fighting with sandbags and seawalls but arrangements are in place for Australia to accept around 280 Tuvaluans a year should their islands become unlivable.
- Jakarta is sinking more due to groundwater extraction than sea level rise, but water intrusion and flooding are still a problem, so it is relocating its administrative centre to a 'green city' in the heart of Kalimantan (Borneo). With Dutch support it is also building a huge seawall.
- Egypt similarly plans to relocate a major part of its capital 30 km inland from the low lying Nile delta.
Bhutan is also building a new city – Gelephu -Mindfulness City. Although carbon neutral itself, the country is facing increased flooding and landslides from melting Himalayan glaciers and heavier rainfall. There are is also fears that agriculture on which the country depends, along with its hydro schemes, will be negatively affected by changes in the available water flows.
The new city – initially for 100,000 but expected to rise to 1 million by 2065, will have many climate smart features and hopes to become a model for other countries.
It will for example, retain 60% of its forest cover, have elevated infrastructure, use carbon neutral or carbon negative materials and Green Infrastructure features such as wetlands.It will also be located at some distance up the slope, not on the floodplain as was common for most of the world’s cities, so that there is less risk of flooding and waste water is filtered before reaching the river. Walkways and public transport will connect the various elements to avoid the need for private cars.
- Faced with over 200,000 properties likely to be at risk from coastal erosion, sea level rise and flooding by 2050, the UK is having to be selective about what can be saved – for example seawalls and barriers will be used in places such as the Thames, but others are likely to be sacrificed. Small villages such as Happisburgh, which are already crumbling into the sea, will most likely opt for staggered relocation further inland, leaving the question of how this is to be funded.
- New Zealand is taking a multipronged approach and is assessing the impact of climate change
on the environment, on communities, on infrastructure and its economy. As part of its climate adaptation strategy, the government will no longer permit public housing to be built in areas subject to inundation and is encouraging private developers to follow suit.
Prospective buyers must be made aware of any climate risks associated with a property.
Additionally, sectors such as energy, transport, water, and waste services are being supported to become more climate-aware and resilient.
Changes to Building Codes, Zoning and Infrastructure
Australia: Flood Design Standards & Community Retrofitting
The "NSW Flood Resilient Buildings Design Guide" offers practical retrofitting strategies: elevated floor levels, flood vents, water-resistant materials.
The ABCB Handbook complements the National Construction Code, guiding structural safety and elevation in flood zones.
Local councils (e.g. Lismore, Brisbane) have piloted community-led rebuilding with modular, elevated housing and flexible zoning overlays.
- Queensland ‘s traditional housing used to be on stilts to take advantage of cooling breezes, but now this idea is regaining traction as a way of reducing the impact of flooding in consequence of heavier rainfall and repeated flooding.
- Following a Parliamentary Inquiry into Resilient Roads, Australia is urging a change of design and construction standards and the use of more resilient and recycled materials to cope with repeated flooding and more intense rainfall.
- Queensland and NSW have trialled elevated roadways and flood-resilient bridges in flood-prone regions, often integrating community feedback and local landscape assessments.
National water boards coordinate with municipalities to enforce zoning restrictions and building elevation mandates.
Homes in places such as Maasbommel, which are designed to float during floods, have buoyant foundations and flexible utilities.
The 'Room for the River' program redesigns landscapes to accommodate flooding, integrating housing, agriculture, and ecology.
After Hurricane Sandy, NYC revised its building codes: elevating utilities, restricting basement use, and mandating floodproof materials.
The FEMA Flood Mapping Program informs zoning and insurance, while HUD funds resilient housing prototypes in vulnerable areas.
Community initiatives in Louisiana and Florida explore elevated modular housing, often co-designed with residents.
These countries are revising national building codes to incorporate flood resilience into both urban and coastal infrastructure. I noticed in Austria recently that electrical connections were no longer allowed to be in basements as they previously were. Other updates include:
-Elevated floor levels
-Waterproofing standards
-Flexible zoning for flood-prone areas
In Denmark, the integration of *ensures that structural design reflects local climate risks, while the *embed functional resilience into planning.
UNDP-supported projects have elevated roads, bridges, and drainage systems to withstand extreme weather.*
The * is climate-proofing over 130 infrastructure units, including irrigation and water supply systems.
Traditional stilt housing, once common in Timor-Leste, proved more flood-resilient than modern concrete structures—once again highlighting the value of vernacular design in climate adaptation.
This is more than enough for now. Suffice to say, instead of filling in wetlands and creating straight concrete channels as former town planners did, to remove water as fast as possible, the aim now is to work with nature and to slow it down as it moves through the landscape and to at least move housing and roads out of its path where that isn't possible. To misquote the Danish planner in the video about Copenhagen, "Yes, at around € 2 million the cost of retrofitting Copenhagen was expensive, but the 2011 flood already cost the community at least half that much" - a harsh reality which many communities and governments are facing or are likely to face more often in future.
Next: We'll take a look at how governments are dealing with rising temperatures.
Much help from both Copilot and Blogger on this post, sometimes too much! I don't always want my work 'refined' or elaborated, but rather to sketch out broad outlines so that people can find the solutions that best fit their circumstances and preferably inspire a whole lot of new ones. I also hate to use jargon. My aim is to make the science accessible to as many people as possible, especially if English is not their first language.
* New feature on Blogger which is supposed to add custom Google links. Not sure if it works yet.
Fairbourne, a coastal village in Gwynedd, has been designated for managed retreat due to rising sea levels and storm surge risk.
- Timeline: The council announced it will cease maintaining flood defences after 2054, effectively surrendering the village to the sea.
- Population: Around 750 residents, many of whom now face mortgage denial, property devaluation, and identity loss.
- Cost of retreat: Estimated at £27 million to dismantle homes, roads, and infrastructure.
- Emotional toll: Residents describe it as being branded “climate refugees,” with no clear relocation plan or compensation.
The 60 residents of Isle de Jean Charles, Louisiana are also being relocated in America’s First Federally Funded Climate Retreat.
This narrow island in the bayous of southern Louisiana has lost 98% of its land since 1955 and is losing 75 km 2 every year and Louisiana is now attempting to restore the marshlands which used to protect the shoreline.
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