A fire damaged tree in forest along the Red Rock Parkway, Waterton National Park, Alberta, Canada. October 2021. © J. Ashley Nixon
Forests have long been recognized as a positive force in the global struggle against climate change. Growing trees, associated forest vegetation and soils act as carbon sinks, absorbing more than they emit when harvested, or forest land is cleared for agriculture or subject to fire. The global carbon flux in and out of forests is estimated to result in a net gain of 7.6 billion tonnes of CO2 per year from the atmosphere. Put in perspective, that’s 1.5 times more than the USA emits each year, but still a relatively small fraction of global emissions from the burning of fossil fuels which have risen to 36 billion tonnes of CO2 per year. Disturbingly, there are signs that this balance may be shifting, at least in some forests in the world.
UNESCO World Heritage sites
A report issued by UNESCO just ahead of the Climate Action Summit in Glasgow (COP26) has revealed that CO2 emissions from at least ten forests in World Heritage sites are now emitting more CO2 than they store. Researchers from UNESCO, World Resources Institute (WRI) and the International Conservation Union (IUCN) used satellite and on-the-ground information to estimate carbon fluxes in the 69 million hectares of forests located in all of the world’s 257 natural and mixed (natural and cultural) UNESCO World Heritage sites.
Overall, the research found that these forests absorb 190 million tonnes of CO2 each year, which is about half of what the UK emits annually from the burning of fossil fuels for energy and cement production.
Despite their global recognition and nationally protected status, ten of these sites were calculated to be net emitters between 2001-2020. That is due to a combination of human factors (logging and land-clearance for agriculture) and the increasing scale and severity of forest fires linked to severe drought and systemic climate change.
Waterton-Glacier International Peace Park
One of those sites is Waterton Glacier International Peace Park which straddles the Rocky Mountains across the Canada-USA border between Alberta and Montana. The researchers who compiled the UNESCO report calculated that these forests were emitting 280 thousand tonnes CO2e/ha/year more than they were absorbing and attributed this change to temperature changes and fire/fire suppression.
The Kenow Wildfire
The Kenow wildfire that struck Waterton National Park in September 2017 burned out more than 19,000 hectares of forest and grassland, which amounted to about 40 percent of the park. It is important to acknowledge that this wildfire, like many others, occurred naturally; the Kenow Wildfire began with an intense lightning storm outside the park boundary. Also, the environmental changes associated with forest fires, such as opening the canopy to let light in and trigger new vegetation growth on the forest floor, have positive attributes. On the other hand, there was massive damage to infrastructure in Waterton National Park, especially along the Akamina and Red Rock Parkways, where bridges, signs and tourist facilities were burned out.
The town of Waterton had to be evacuated, although, miraculously, the majority of buildings avoided damage, and business returned the following year after its planned and regular winter shut down. It was indeed a different experience hiking in the park in 2018, but my visit in 2021 revealed a widespread return of young trees and signs of good forest recovery.
The big fear is that delayed efforts to bring down global CO2 emissions to net-zero by the middle of the century may not be enough to avert the growing scale and intensity of forest fires in Western Canada and the United States in the decades to come.
World Heritage site net carbon emitters
Ten UNESCO World Heritage sites were found to be net carbon contributors from 2001-2020. These are 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).