Over the last 30 years, global and UK tide-gauge records show a clear acceleration in sea-level rise.

London’s relationship with water is as old as the city itself. Today, that relationship is changing faster than many residents realise: sea levels around the UK are rising, storm surges are becoming more frequent, and the choices made now about homes, insurance, and planning will shape which neighbourhoods thrive, and which may be lost, over the next decades. The local picture: how sea-level rise is already affecting the Thames Estuary community.

For properties along the tidal Thames, from Greenwich and Tower Hamlets through to riverside communities upstream, the immediate effects are concrete: increased frequency of nuisance flooding, costly temporary closures of riverside infrastructure, and rising premiums or difficulties renewing home insurance for some households. The City of London and Environment Agency maintain and upgrade tidal defences (most visibly the Thames Barrier), but the need for more frequent closures and long-term adaptations is growing. The Thames-side economy, offices, cultural venues, and riverside housing now face both physical risk and higher operating costs that feed through to rents and living costs. (City of London, 2024; TE2100, Environment Agency). 

Long-run trends: 1975–2025 and why the last 30 years matter: Global and UK tide-gauge records show a clear acceleration in sea-level rise. Long-term measurements indicate roughly 19–20 cm of rise around the UK since 1901, with much of that increase concentrated in recent decades; recent analyses suggest the UK’s Sea levels have risen faster than the global average in the past 30 years. The Met Office’s UK marine projections and Environment Agency analyses confirm that mean and extreme sea levels have increased and that extremes are becoming more common. These observed trends, driven by ocean thermal expansion, melting land ice, and changing ocean circulation, mean that the 1975–2025 period saw both steady mean sea-level rise and a marked increase in damaging coastal flood events. (Financial Times)

Looking forward: projections to 2050 and beyond (2025–2050+): Official UK projections present a range of futures depending on global emissions and ice-sheet behaviour. Updated UK projections and the 2024/25 national assessment underscore a sobering possibility: by 2100, UK sea levels could rise by over a metre under high-end scenarios, and extreme “once-in-a-century” tidal events may become annual occurrences before the end of the century. For 2025–2050 specifically, the expected rise is smaller in absolute terms than later decades but still material, enough to increase the frequency of coastal flooding events and to make some low-lying assets repeatedly vulnerable unless defences and planning are strengthened. Local plans such as the Thames Estuary 2100 (TE2100) lay out staged short, medium, and long-term responses because the lead times for large defences and managed retreat are long (GOV.UK).

Insurance, markets, and the social consequences: The insurance market is already shifting in response. Insurers reported record weather-related claims in 2024, and industry bodies warn of steadily increasing payouts for flood and storm damage; some insurers have reduced exposure in high-risk areas, and underwriting has become tighter. In the UK, the government-industry Flood-Fire insurance programme has improved the availability and affordability of insurance for many homes at flood risk since 2016. Still, it is time-limited and ends in 2039, raising concerns about the transition to fully risk-reflective pricing. Where premiums rise, or coverage becomes harder to secure, mortgage availability and property values can be affected, compounding the social impact in lower-income and high-risk communities. 

Planning and coastal geography: defence, retreat and nature-based options: Local and national authorities are pursuing a mix of responses: hard engineering (barriers, sea walls), nature-based solutions (saltmarsh restoration, managed realignment), property-level resilience measures, and, in some places, planned retreat. TE2100 exemplifies phased planning: short-term actions for the next 25 years, medium-term measures to 2050, and strategic options to the end of the century, including potential major infrastructure upgrades (e.g., barrier works). Nature-based approaches are gaining traction because they can provide adaptive flood storage, biodiversity benefits, and reduced long-term costs, but their application requires space and significant land-use changes. 

What is being done, how long it will take, and at what cost: Nationally, successive packages of capital funding have been committed to flood and coastal defence; the precise programs vary year to year. Large defence projects and estuary-scale plans typically run on multi-decadal timetables, with planning, consents, and construction spanning 5–30 years, depending on scale. The TE2100 phasing explicitly contemplates short, medium, and long-term timeframes because interventions must align with the evolving hazard. Costs vary enormously by approach: local property-level measures (raising electrics, flood-resilient fittings) cost thousands per dwelling; local seawalls or embankments can run into tens or hundreds of millions for communities; major estuary-wide or barrier projects run to the billions. Government and industry documents and announcements since 2022 show targeted funding increases and programmes to accelerate resilience, but the need for sustained, long-term investment remains acute. 

Trade-offs and limits: Should development in at-risk areas be restricted? From a resilience perspective, it is increasingly hard to justify unrestricted new development in areas that modelling shows will be repeatedly flooded before mid-century. Many experts and the CCC recommend stronger planning rules to avoid locking in assets and communities to high future risk; where development proceeds, it should be conditionally permitted only when combined with robust, funded adaptation measures and demonstrable long-term defence commitments. 

 Sea-level rise is no longer a distant imagination: it is a present, accelerating reality that demands combined solutions, engineering, ecological restoration, fair insurance policy, and intelligent planning. For the Thames Estuary and similar UK communities, the practical prescription is clear: (1) accelerate stepped-up planning restrictions, stronger building standards, and incentives for relocation (where appropriate) will be needed to avoid social injustice; otherwise, low-income households are likely to bear disproportionate costs. (Committee on Climate Change, 2025). 

The human story: what it looks like on the ground in the Thames Estuary: For riverside residents, the narrative is familiar: a few more disrupted commutes due to closures, a higher-priced insurance renewal, a council consultation about potential managed realignment or a new sea wall, and the slow, grinding work of adapting riverside businesses. For others, particularly private renters, mobile home residents, and owners of older stock built in floodplains, the reality can be losing insurance cover entirely or living with precarious, recurring flood damage. These effects ripple: local economies suffer, household finances are stressed, and community cohesion can fray after repeated events. Coverage programs like Flood Re cushion many households but do not eliminate the long-term economic and social costs. 

Conclusion: (1) Prioritize defence and nature-based adaptation where net benefits are clear; (2) reform planning to stop high-exposure building without funded protection; (3) transition insurance arrangements so that premiums and risk signals incentivise resilience but do not leave vulnerable households unprotected; and (4) invest in social support for areas where retreat becomes the most responsible option. These are costly and politically hard choices but postponing them will multiply human and economic losses.

This Post was submitted by Climate Scorecard UK Country Manager, Cesar A. A. Da Silva. 

Resources

Association of British Insurers (ABI) (2024). Weather-related insurance claims reach new highs, industry statement. ABI, London.

City of London Corporation (2024) City of London Riverside Strategy. City of London Corporation, London.

Committee on Climate Change (2025) Progress in Adapting to Climate Change: 2025 Report. Committee on Climate Change, London.

Environment Agency (2021) Exploratory Sea Level Projections for the UK to 2300. Environment Agency, Bristol.

Environment Agency (n.d.) Thames Estuary 2100 (TE2100) Plan. Available at: https://www.gov.uk/government/publications/thames-estuary-2100-te2100 (Accessed: 20 November 2025).

Financial Times (2025) ‘UK sea level rising faster than the global average, study finds’, Financial Times, 14 January.

Flood Re (2022) Build Back Better Scheme Overview. Flood Re, London.

Flood Re (2024) Annual Review 2024: Flood Risk and Insurance Trends. Flood Re, London.

Met Office (2023) UKCP Sea-Level Rise and Storm Surge Factsheet. Met Office, Exeter.

Reuters (2024) ‘UK insurers pay out record claims as extreme weather events surge’, Reuters, 12 August.

UK Government (2025) National Assessment of Flood and Coastal Erosion Risk in England: 2024 Summary Report. Department for Environment, Food & Rural Affairs, London.