Nearly 90% of UNESCO-designated sites are under high environmental stress, new report finds
Climate change impacts recorded in 98% of sites, including extreme heat, glacier loss and ocean acidification
Wildfires have emerged as the leading driver of forest change in World Heritage sites
Over 300,000 sq km of tree cover lost since 2000, with invasive species present in more than 80% of sites
More than a quarter of sites could reach critical, potentially irreversible tipping points by 2050
Nearly 90 per cent of sites designated by the United Nations Educational, Scientific and Cultural Organization (UNESCO) are currently experiencing high levels of environmental stress, a new report has found.
The UNESCO People and Nature Report is the first assessment across all UNESCO categories such as World Heritage Sites, Biosphere Reserves and Global Geoparks. It brings together a single network of more than 2,260 sites spanning over 13 million square kilometre, an area larger than China and India combined.
The report highlights growing human pressures and the intensifying impact of climate change across these globally significant landscapes.
Climate change has emerged as a major driver of vulnerability, with 98 per cent of sites experiencing at least one extreme climate condition, including extreme heat, glacier loss, ocean acidification and increased natural hazards, since 2000.
The authors note that extreme heat is the most widespread hazard, followed by heavy rainfall, rising sea levels and coral bleaching. Other pressures include habitat degradation, droughts, wildfires, pollution, invasive species, water stress and landslides.
Glacier loss in UNESCO sites has exceeded 2,500 gigatonnes of ice since 2000, with mountain glaciers losing around 9 per cent of their volume over the same period. Oceans within these sites have also become more acidic compared to levels recorded in 2000.
Extreme weather events such as droughts, floods and wildfires have increased by 40 per cent in the past decade.
The report finds that wildfires have now become the primary driver of forest change in World Heritage sites, followed by logging, land cleared for permanent agriculture and infrastructure development such as roads, railways and energy projects.
Since 2000, more than 300,000 sq km of tree cover has been lost, while invasive species have been recorded in over 80 per cent of UNESCO-designated sites.
The report warns that, with rising risks and increasing human disturbance, more than a quarter of UNESCO-designated sites could reach critical tipping points by 2050, some of which may be irreversible.
Among the most concerning risks is the potential collapse of ecosystems such as tropical coral reefs, where bleaching could become an annual event, leading to their functional disappearance.
More than 300 World Heritage sites are already facing chronic water stress, threatening freshwater ecosystems. Declining forest carbon stocks could also turn some carbon sinks into net carbon sources.
Despite mounting pressures, UNESCO sites continue to act as important buffers against biodiversity loss. The report notes that habitat degradation within these areas has been about half as severe as in surrounding landscapes over the past 50 years.
“While global wildlife populations have declined by approximately 73 per cent since 1970, populations within UNESCO-designated sites have remained stable,” the report states.
These sites are home to more than 60 per cent of globally mapped species, with around 40 per cent endemic to these areas, and together account for about one-fifth of the world’s key biodiversity areas.
They also support nearly a third of the remaining populations of iconic wildlife such as elephants, tigers and pandas, as well as critically endangered species including the vaquita, Javan rhino and pink iguana.
Beyond biodiversity, UNESCO-designated sites play a crucial role in climate stability, absorbing nearly 700 million tonnes of carbon dioxide annually — roughly equivalent to Germany’s annual fossil fuel emissions.
They store an estimated 240 gigatonnes of carbon in soils and sediments, with forests acting as major terrestrial sinks and coastal ecosystems such as mangroves and seagrasses capturing blue carbon.
These landscapes also support the livelihoods of nearly 900 million people or about 10 per cent of the global population, and contribute close to 10 per cent of global GDP. More than half of these sites are located in major tourism destinations, attracting nearly 1.5 billion visitors each year.
They underpin agricultural and food systems by providing freshwater, energy and raw materials. For example, the Arganeraie Biosphere Reserve in Morocco uses agroforestry systems to support food production and grazing.
The report also highlights the importance of pollinators, noting that nearly 75 per cent of global crops depend on species such as bees, contributing an estimated $500 billion to the global economy. UNESCO initiatives like “Women for Bees” support sustainable beekeeping, including in India’s Western Ghats.
Nature-based solutions within these sites help protect communities from hazards such as floods and landslides, potentially preventing up to $53.7 trillion in damages globally.
The report concludes that these sites can serve as models for sustainable development. For instance, it highlighted how community-led management in Lake Malawi National Park has curbed illegal fishing, safeguarding both food security and livelihoods for 34 local communities.
In another example, it pointed to sustainable agroforestry initiatives in the Amazon, where riverine families produce essential oils from rosewood and copal, supporting inclusive governance while building resilient, sustainable businesses. In Chile’s Lauca Biosphere Reserve, reviving ancestral vicuña shearing practices provides local communities with income from high-value vicuña fibre while protecting the species.
The report adds that integrating indigenous knowledge with modern science can strengthen resilience, enabling local communities to manage their landscapes and adapt to environmental change.