Photo: IUCN/Wendy Strahm
Climate change is the biggest threat to natural World Heritage sites, but these sites can be part of the solution
Impact on natural World Heritage sites
Climate change continues to affect more and more natural World Heritage sites. It has now become the most prevalent threat to these sites, according to the IUCN World Heritage Outlook, which tracks the conservation of all natural World Heritage sites.
The IUCN World Heritage Outlook 3, published on 2 December 2020, assesses climate change as a high or very high threat in 33% (83 out of 252) of natural World Heritage sites – up from 26% in 2017 (62 out of 241), and from 15% in 2014 (35 out of 228 sites listed at the time). Invasive alien species, which was assessed as the top threat both in 2014 and 2017, follows closely behind climate change as now the second most prevalent threat to natural World Heritage.
Given the evidence that links the spread of invasive alien species with climate change impacts on ecological parameters, a strong link between these two threats is highly likely. Examples where climate change has facilitated the spread of invasive alien species include Cape Floral Region Protected Areas (South Africa) and Garajonay National Park (Spain).
In some sites, increasing impacts associated with climate change (sometimes accompanied by other threats and issues) have resulted in a deteriorated conservation outlook, as is the case with the Great Barrier Reef (Australia), which is now assessed as having a “critical” outlook. Ocean warming, acidification and extreme weather have contributed to dramatic coral decline in the site, and as a result decreasing populations of marine species.
Climate change is also associated with increasing frequency and severity of fires, as was exemplified by some sites that have faced unprecedented fires in 2019-2020, such as Gondwana Rainforests of Australia (Australia) and Pantanal Conservation Area (Brazil). In some cases the combination of climate change, increasing fires and the associated spread of invasive alien species is already changing the sites’ ecosystems.
In Kluane Lake, located in the Kluane / Wrangell-St Elias / Glacier Bay / Tatshenshini-Alsek World Heritage site (Canada/USA), the rapidly melting Kaskawulsh Glacier has changed the river flow, depleting fish populations. According to a 2019 study co-authored by IUCN, glaciers are set to disappear completely from almost half of World Heritage sites by 2100 if business-as-usual emissions continue.
While only coordinated global efforts can help address the threat of climate change, it is important to increase resilience of threatened sites by limiting other pressures to a minimum.
Nature-based solutions to climate change
Natural World Heritage sites are not just iconic places with exceptional nature, they also provide benefits that contribute to human well-being, according to ‘The Benefits of Natural World Heritage’ study by IUCN and UNEP’s World Conservation Monitoring Centre.
Natural World Heritage sites contribute to global climate stability by storing significant amounts of carbon. Forests found in World Heritage sites across the tropical regions store 5.7 billion tons of carbon.
Two-thirds of natural sites on the UNESCO World Heritage List are crucial sources of water and about half help prevent natural disasters such as floods or landslides.
In India and Bangladesh, the Sundarbans’ 2,200km mangrove coastline offers flood protection, which would otherwise require an investment of US$ 300 million in man-made infrastructure.
The Benefits report features a total of 23 case studies, including three which highlight how World Heritage sites contribute to responding to climate change:
- Sundarbans National Park (India) and The Sundarbans (Bangladesh)
- Ibiza, Biodiversity and Nature (Spain)
- Canadian Rocky Mountain Parks (Canada)
A wilderness approach to help respond to climate change
IUCN's 2017 report, “World Heritage, Wilderness, and Large Landscapes and Seascapes”, argues that protecting large intact land- and seascapes is a crucial strategy to address climate change and biodiversity loss, as these irreplaceable areas provide greater benefits and host more plant and animal species than smaller, more disturbed areas.
Natural World Heritage sites often include very large areas: the 241 sites listed for their natural values account for 8% of the total surface covered by all 230,000+ protected areas worldwide. Large sites with wilderness values include iconic places such as the Galapagos Islands in Ecuador, Yellowstone National Park in the USA and the Okavango Delta in Botswana.
Wilderness areas help respond to climate change, for instance stocking huge amounts of carbon and serving as refuge for species which are forced to migrate due to a changing climate. However, they are also under severe threat from climate change, and are continuously being cleared, degraded and fragmented, largely due to industrial activities such as oil and gas extraction, mining, logging, agriculture, construction of roads and dams. The wilderness left on land now covers less than a quarter of Earth’s total land surface.
On land, natural World Heritage sites cover 1.8% of the world’s remaining wilderness area, while at sea 0.9% of marine wilderness has World Heritage status. The World Heritage Convention can do more to protect wilderness. Providing guidance on how this can be achieved, the report identifies broad gaps in the World Heritage List’s wilderness coverage.
