The first ever scientific assessment of the amounts of greenhouse gases emitted from and absorbed by forests in UNESCO World Heritage sites has found that at least 10 key sites have been net carbon sources over the past 20 years, meaning that they have given off more carbon than they sequestered, due to pressure from human activity and climate change.
World Heritage forests absorb 190m tons of CO2 each year
By combining satellite-derived data with monitoring information at site level, researchers at UNESCO, the World Resources Institute (WRI) and the International Union for Conservation of Nature (IUCN) were able to estimate the gross and net carbon absorbed and emitted by UNESCO World Heritage forests between 2001 and 2020 and determine the causes of some emissions.
The research found that, as a whole, forests contained in natural World Heritage sites, absorb the equivalent of approximately 190 million tons of CO2 from the atmosphere each year, comparable to roughly half the United Kingdom’s annual CO2 emissions from fossil fuels. “We now have the most detailed picture to date of the vital role that forests in World Heritage sites play in mitigating climate change,” said Tales Carvalho Resende from UNESCO who co-authored the report.
World Heritage forests, whose combined area of 69 million hectares is roughly twice the size of Germany, are biodiversity-rich ecosystems. As well as absorbing CO2 from the atmosphere they also store substantial amounts of carbon. Carbon sequestration by these forests over centuries has led to total carbon storage of approximately 13 billion tons of carbon, which is more than the carbon in Kuwait’s known oil reserves. If all this stored carbon were to be released into the atmosphere as CO2, it would be akin to emitting 1.3 times the world’s total annual CO2 emissions from fossil fuels.
Findings from 10 World Heritage forests are cause for concern
However, given that World Heritage sites are highly prized and protected, the fact that 10 of these forests emitted more carbon than they captured due to different disturbances and pressures is alarming.
Causes of increased emissions vary, according to findings on threats from the IUCN World Heritage Outlook. At many sites, human activities such as logging and the clearance of land for agriculture cause emissions to be greater than sequestration. The increasing scale and severity of wildfires, often linked to severe periods of drought, is also a predominant factor in several cases. Other extreme weather phenomena, such as hurricanes, contributed at certain sites. IUCN’s Outlook 3 report issued in December 2020 assessed climate change as the biggest threat to natural World Heritage.
“All forests should be assets in the fight against climate change. Our report’s finding that even some of the most iconic and best protected forests such as those found in World Heritage sites can actually contribute to climate change is alarming and brings to light evidence of the severity of this climate emergency”, said Tales Carvalho Resende.
In the coming years, ongoing sequestration and carbon stores are likely to be affected at a growing number of sites worldwide as a result of increasingly fragmented and degraded landscapes, and more frequent and intense climate-related events.
Better management of sites can yield results
The report urges strong and sustained protection of UNESCO World Heritage sites and their surrounding landscapes to ensure their forests can continue to act as strong carbon sinks and stores for future generations. To achieve this, the report recommends rapidly responding to climate-related events, as well as maintaining and strengthening ecological connectivity through improved landscape management.
For example, in Indonesia, government agencies have been using near real-time fire alert systems to significantly reduce their average fire response time. Rapid response is integral to preventing fires from developing into destructive conflagrations that produce extensive emissions.
And at the Sangha Trinational World Heritage site, located within Cameroon, the Central African Republic and the Republic of Congo, the creation of a buffer zone around the site has helped to ensure that surrounding human activity is not adversely impacting the site. The buffer zone itself is also an important carbon sink.
The report also recommends integrating the continued protection of UNESCO World Heritage sites into international, national and local climate, biodiversity and sustainable development strategies in line with the Paris climate agreement, the Post-2020 Global Biodiversity Framework and the Sustainable Development Goals.
“This analysis of iconic World Heritage sites shows that combining satellite data with on-the-ground information can improve local decision-making and strengthen accountability, thereby helping forests, climate, and people,” said David Gibbs, WRI Research Associate and co-author of the report.
“World Heritage sites include some of the planet’s largest undisturbed forests that not only stock huge amounts of carbon but also serve as refuge for many iconic species. Protecting these sites from increasing fragmentation and escalating threats will be central to our collective ability to address climate change and biodiversity loss”, said Tim Badman, Director of IUCN’s World Heritage Programme.
The following UNESCO World Heritage sites were found to be net carbon contributors from 2001-2020; the Tropical Rainforest in Sumatra (Indonesia), the Río Plátano Biosphere Reserve (Honduras), the Yosemite National Park (USA), the Waterton Glacier International Peace Park (Canada, USA), the Barberton Makhonjwa Mountains (South Africa), Kinabalu Park (Malaysia), the Uvs Nuur Basin (Russian Federation, Mongolia), Grand Canyon National Park (USA), the Greater Blue Mountains Area (Australia) and the Morne Trois Pitons National Park (Dominica).
Header image: Peter Howard/IUCN.