Climate change top threat to natural World Heritage
The IUCN World Heritage Outlook 3 builds on previous reports from 2014 and 2017 to track whether the conservation of the world’s 252 natural World Heritage sites is sufficient to protect them in the long term
Updated On - 12:47 AM, Mon - 11 January 21
Climate change is now the biggest threat to natural World Heritage, according to a report published today by International Union for Conservation of Nature(IUCN). A third (33%) of natural World Heritage sites are threatened by climate change, including the world’s largest coral reef, the Great Barrier Reef, assessed as having a “critical” outlook for the first time.
The IUCN World Heritage Outlook 3 builds on previous reports from 2014 and 2017 to track whether the conservation of the world’s 252 natural World Heritage sites is sufficient to protect them in the long term. It finds that climate change has overtaken invasive species as the top threat to natural World Heritage.
Marine population declining
Among the 83 natural World Heritage sites now threatened by climate change is the Great Barrier Reef, where ocean warming, acidification and extreme weather have contributed to dramatic coral decline and as a result decreasing populations of marine species.
In the Cape Floral Region Protected Areas of South Africa, climate change has exacerbated the spread of invasive species, while the Pantanal Conservation Area of Brazil was badly damaged by the unprecedented 2019-2020 wildfires.
Glacier melting

In Kluane Lake, located in a World Heritage site in Canada and the USA, the rapidly melting Kaskawulsh Glacier has changed the river flow, depleting fish populations.
Impact
While lower tourist numbers may ease pressure on some ecosystems, in more cases impacts appear negative. Closing sites to tourism causes significant revenue loss, and illegal activities are on the rise with fewer staff deployed to prevent them.
Assessment
The IUCN Outlook assesses the prospects for World Heritage site values – the unique features which have earned them their World Heritage status – based on threats, and how good protection and management is.
It assesses 63% of sites as either “good” or “good with some concerns”, while 30% are of “significant concern” and 7% are “critical”. Half of the sites are found to have “effective” or “highly effective” protection and management, with the sustainability of the sites’ funding being the most common issue rated as a “serious concern”.
The Outlook finds that 16 natural World Heritage sites have deteriorated since 2017, while only eight have improved.
Some relief

The outlook of Comoé National Park continues to improve and is now “good with some concerns” after moving from “critical” in 2014 to “significant concern” in 2017. Thanks to political stability, effective management and international support, populations of chimpanzees, elephants and buffalos are stable, and rare birds are starting to return.