World Heritage Day 2025: Heritage Under Threat

April 18 is World Heritage Day, a moment to celebrate the world’s cultural and natural treasures—and to reflect on the challenges they face. This year, the global theme is “Heritage under Threat from Disasters and Conflicts: Preparedness and Learning from 60 Years of ICOMOS Actions.”

At Historic Houses, we stand with our international peers in recognising the importance of protecting historic places not only in times of peace and prosperity, but also in moments of crisis. The UK’s independent historic homes are deeply woven into the nation’s cultural fabric. They have endured centuries of change—wars, fires, economic upheaval, and natural disasters. Today, they continue to face new and complex risks, from climate change to the evolving demands of modern conservation.

Climate change is perhaps the most serious threat facing heritage—an existential challenge for the world and for the buildings and landscapes we treasure. But more specifically, the climate crisis produces several challenges for heritage buildings and gardens. Although they may have stood for centuries, historic buildings were not designed for the increasingly erratic weather that climate change throws at them. Storms in recent years have affected many of our members across the country, such as Cirencester Park in Gloucestershire, which had to close multiple times this winter due to storms, and Plas Cadnant Hidden Gardens, which suffered severe damage in 2015. Last year, Broughton Castle’s 13th century kitchen was inundated, posing serious risks of damp and of an infestation in the Oak Room. Thankfully this was averted but it could have proved disastrous.

Climate change’s challenges aren’t just restricted to buildings. They are even more keenly felt in historic gardens. Rising temperatures and changing weather patterns could wipe out decades of careful cultivation and planting, whilst declining biodiversity makes disease a bigger threat to the UK’s historic gardens. At Easton Walled Gardens, migratory species are in decline, with fewer swallows and flycatchers having almost vanished.

At Brook Hall, meanwhile, rising sea levels are already leading to increased salinity in the soil of the walled garden, making it harder to grow heritage varieties of produce that have thrived there for generations. This kind of subtle but steady environmental change threatens the long-term sustainability of these cherished landscapes and the cultural practices tied to them.

The ripple effects of these changes go far beyond planting plans. Birds, insects, and other wildlife play a crucial role in garden health – pollinating plants, keeping pests in check and maintaining ecological balance. Their disappearance not only makes the gardens less dynamic, but it also undermines the very systems that help them thrive.

This might feel overwhelming but without urgent action, the consequences will be catastrophic. Fortunately, there is some positive and important work already being done to respond to the threat of climate change. In East Anglia, there have been significant rewilding efforts at Somerleyton and at Holkham, whilst on the Knepp Estate in Sussex, the course of the River Adur has been changed back to its more natural shape and its floodplains restored to reduce flooding.

Penpont offers a powerful example of how heritage and sustainability can work hand in hand. With its Victorian walled garden producing organic vegetables, broadleaf woodlands managed for biomass and biodiversity

Places like Athelhampton, Muncaster Castle and Larchfield (one of the few carbon negative companies in the UK) show how historic estates can decarbonise through investing in energy efficiency and renewable energy sources like biomass. Domestic homes represent a huge portion of the UK’s total carbon emissions, and older properties tend to be less energy efficient than the average, so it’s clear that heritage must be part of the conversation on building decarbonisation.

Historic buildings face significant barriers to becoming more climate resilient and decarbonising, primarily through the planning system. In a survey of our members, 87% said that they actively want to decarbonise but that the planning system was a barrier to them doing so. We continue to advocate for policy changes, such as Local Listed Building Consent Orders like those in Kensington and Chelsea, to enable heritage to become more climate resilient and decarbonise. Historic buildings and gardens can play important roles in the transition to net zero but only with the right support.

The disasters facing heritage in the UK are by no means as severe as those for many across the world, but World Heritage Day is a chance to us to reflect on challenges and embrace opportunities to act. With the right policies, investment, and urgency, we can ensure that historic buildings and gardens continue to thrive for generations to come.