Well-adapted waste system

Risk to the system from climate change: heavy rainfall, landslides, sea-level rise, and coastal erosion impact the waste system.

Objective

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Waste sites are managed safely and do not harm people or the environment.

Proposed target: by 2035, all mining tips should have been assessed and tips in the highest risk categories should be effectively adapted to ensure they are no longer a risk to public safety from landslides.
Proposed target: by 2030, all sites should have been assessed and categorised by risk level to identify the sites where adaptation is most needed. By 2050, all sites classified as at high risk of harm from the release of hazardous waste into the environment due to flooding, waterlogging or coastal erosion, should be effectively adapted.

Actions

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Disused mining tips: site drainage, slope stabilisation.

The main approaches for reducing the risk of landslips from disused mining tips are to improve the drainage of the site and to stabilise slopes. Slopes can be re-profiled and stabilised with erosion control matting or with planting. The costs of earthworks and drainage will vary depending on site geography and estimates range from £100,000 to over £1 million per tip (2025 prices). However, remediation works following a major landslip can be more costly. For example, remediation following the Tylorstown landslip (£15 million, 2025 prices) included emergency drainage, reinstatement of a riverbank, and the relocation of a large volume of material. Besides costs, the potential risk to life and from wider damages makes an urgent case for adapting high-risk sites.

Historic landfills: defending waste sites with coastal or flood defences or new covers, waste treatment to stabilise or remove hazardous materials, and partial or full excavation of waste to another site.

Defending the waste site: waste sites can be defended by either installing a coastal or flood defence, or a new cover system to the landfill. This protects landfill sites from erosion or flooding and reduces the risk of pollutant release into waterways. The cost of coastal or flood defences can vary significantly depending on the site and type of defence. Case studies have estimated costs of £2.7 million to defend sites with coastal revetments, up to £12 million for installing a sea wall, with limited evidence available for inland sites (2025 prices). More costly schemes may only be viable in cases when other types of infrastructure or homes would also be protected.
Treat wastes to stabilise or remove hazardous materials: wastes can be treated so they are stabilised, or the most hazardous materials are removed. This could involve physical extraction and sorting of hazardous materials or applying chemical or biological agents to de-contaminate or stabilise the materials.
Excavation of wastes to another site: wastes can be permanently removed and re-located to another site. Full excavation of a site is often the costliest option, particularly where sites contain a large volume of material. Partial excavation is an option particularly when only certain parts of the site are vulnerable or contain hazardous materials. Landfill mining to recover and reuse excavated materials could be an option to improve cost effectiveness. However, this is a novel approach requiring further research.

These adaptation actions are connected with adaptation in the built environment and communities system.

Enablers

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Resources: to support responsible bodies to fund monitoring and adaptation of waste sites.

Often local authorities own historic waste sites, or it is challenging to identify a liable private landowner, which means that the costs of adaptation fall to local authorities or government bodies. Funding constraints on local authorities are commonly identified as a barrier to adapting historic waste sites, given the potentially significant cost. Currently the landfill tax is cited as financial barrier to excavating and relocating wastes in historic landfills. Governments could consider whether exemptions may be appropriate in circumstances where excavation is the best adaptation option.

Clear plans, roles, and responsibilities: for responsible bodies to monitor and manage climate risks to mining tips and historic waste sites, providing consistency and accountability.

Wales has recently set up a public body with the responsibility for ensuring the safety of all tips in Wales. In Great Britain, the Mining Remediation Authority is responsible for managing tips that it owns, but this is less than 1% of the total number of tips. Local authorities can act to undertake emergency works on other tips, but this is generally on a more reactive basis and there is no obligation for proactive monitoring. For historic landfills, local authorities in England, Scotland, and Wales have powers to monitor and manage sites causing pollution. However, often these powers are not being used due to a lack of technical expertise and resources. In Northern Ireland, regulation giving local authorities powers to enforce remediation has not been commenced.

Data and monitoring processes: to assess which sites require adaptation action and how that might change in the future, and the associated costs.

Better data are needed to make an initial assessment of which historic landfills require adaptation. Whilst there is already a relatively good understanding of the scale of risk posed by coal tips in Wales, assessments also need to be made for coal tips in other nations and non-coal mining tips. Monitoring is then needed at high-risk sites to assess whether conditions change.

Assessments by local authorities to identify which historic landfills require adaptation action are not consistent and data to inform this are missing or patchy. Historic landfill maps are not publicly available for Northern Ireland or Scotland. Good data on changing exposure to erosion rates and flooding would also support this.
The Department for Environment, Food and Rural Affairs (Defra) are undertaking a desk review to assess which coastal landfill sites in England have a higher risk profile using existing datasets. However, sampling and monitoring of sites identified as higher risk is needed to fully understand the type of intervention required. Data to inform prioritisation are also needed for inland sites in England, and throughout Northern Ireland, Scotland, and Wales.
Data to assess the costs of adapting historic landfills are limited to a very small number of case studies, which makes it challenging for local government to build a business case for action.
Whilst the risk of disruption to municipal and commercial waste services and sites is low, better monitoring of how much disruption is related to climate hazards would enable governments to assess if further action may be needed in the future.

Policies

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Regulatory powers: to clarify responsibility and assign sufficient resource for managing historic landfill sites and mining tips across the UK.

Clear responsibility and sufficient resource will improve knowledge of which sites require adaptation and accountability for delivery. This should include developing a framework for assessing when intervention is required, and compelling landowners or local authorities to intervene immediately at sites which pose an imminent risk.

For mining tips, the Welsh Disused Mine and Quarry Tips Act is a good example of how mining tips can be managed. However, this kind of approach is absent from other nations. This means that the risk from mining tips outside Wales is not being consistently monitored, and powers to intervene are weaker.
For historic landfill sites:

In Northern Ireland, the commencement of powers to manage contaminated land is needed, alongside appropriate guidance and resource for councils for monitoring and enforcement.
In England, Scotland, and Wales, local authorities have powers to manage historic landfills, but they are not being fully used due to a lack of capacity and technical expertise. Funding and better guidance is needed to overcome this barrier, including defining a methodology for systematically assessing the risk level and the threshold at which intervention is required. For sites which pose an imminent risk, responsible bodies should be required to adapt sites immediately.