In Wales, there are nearly 2,500 coal tips -- sites where waste material removed from the ground during coal mining is dumped -- no longer in use. But these Welsh coal industry relics still pose a threat to people living nearby today. Due to heavier rainfall brought on by climate change, a Welsh government report concluded that even "legacy" tips can't be assumed safe and recommended setting up an alert system for landslides similar to the ones used for tsunamis.

"It makes you worried every time that it rains that something could happen, not just for me but for the 327 other high-risk tips out there in Wales," Phil Thomas told the BBC.

Why This Matters

The harms and risks of coal extend beyond burning it for fuel. Even without climate risks, coal waste piles were dangerous -- they can cause landslides, pollution, and spontaneous combustion. In Wales, record-breaking precipitation and multiple landslides in 2020 prompted the government to reassess the safety of coal tips in the era of climate change. The conclusion: current management policies are "​​neither sufficiently robust nor fit for purpose." As coal infrastructure is phased out around the world, the safe decommissioning of mines, waste sites, and power plants will be essential.

Coal Infrastructure, Repurposed

Just 10 years ago, 40% of the UK’s energy came from coal. Today, the country has two remaining coal plants and plans to end coal-fired power by the end of 2024. While the waste material sites pose their own problems, the mines themselves could be part of the solution: All of the coal mines that have closed across the country have naturally filled with warm water, and people are starting to harness their geothermal ability to provide heat. With about a quarter of UK residents living above an abandoned mine, the UK Coal Authority sees huge potential, and is looking into 70 projects that would use the warm below-ground water to heat buildings above.

The use of mine water for heating could help decarbonize the UK's heating sector, which consumes about half of the country's energy. Gas currently dominates as the energy source for heat at about 70%, but it will need to be phased out in order to hit net-zero emissions by 2050. Swapping out a carbon-emitting heat source for a neutral one like mine water could be especially important with the EU’s plans to create a carbon market for heating.

The switch could be, as the BBC wrote last year, "a serendipitous circle of history" where the coal industry's "extractive past could be repurposed for a greener, cleaner future."