(CNN) – Researchers have found that human activity and disasters caused by climate change have transformed the planet’s 10 internationally recognized forests, also known as World Heritage Sites, from absorbing carbon to emitting carbon.
A UNESCO report states that these places can absorb approximately 190 million tons of carbon dioxide from the atmosphere each year, about half of the UK’s annual fossil fuel emissions.

But in the past 20 years, many of these sites have shown increases in emissions, some even exceeding the amount of carbon they removed from the atmosphere.

According to UNESCO researchers, there are two main factors causing forests to change from being sinks to carbon sources: extreme weather events caused by climate change, such as Forest firesand storms and Drought, and human pressures on land use, such as illegal logging, logging and agricultural practices such as grazing.

Given the scale of these forests, Tales Carvalho Resende, Project Officer at UNESCO’s Natural Heritage Unit and co-author of the report, says this is an increasingly global problem, which means global action is needed.

“What the results reveal here is that it’s not necessarily a problem with a specific country or region, but it’s really a global problem,” Resende told CNN. “When we see the 10 places that have become carbon sources, they are scattered all over the world, so the conclusion of the results is that climate action is required at a global level.”

A woman sits near Yavapai Point, on the cliff of the South Rim, overlooking the Grand Canyon, one of the three United States World Heritage Sites, which, according to UNESCO, has become a carbon emitter.

From the Congo Basin to all Redwood National and State ParksThe planet’s 257 World Heritage forests cover nearly 700,000 square kilometers of land, nearly twice the size of Germany.

But the report shows that since 2000, threats from extractive industries, environmental degradation and climate change have been recorded in about 60% of World Heritage sites, which have lost more than 348,600 hectares of forest, an area larger than the size of Belgium. Of the ten sites that have become a source of carbon emissions, three are in the United States.

The report’s findings are a timely warning about restrictions on trees and forests as a climate solution. Leaders and negotiators will meet in Glasgow, Scotland from Sunday to discuss ways to limit global warming, and planting trees is one of the top four priorities identified by the UK government, which is chairing the event.

Protecting forests and planting trees have huge potential to absorb carbon from the atmosphere, but in a rapidly changing world, trees in fire-prone areas could become part of the world. The problem, not the solution, as these UNESCO sites show.

Two people walk through an area ravaged by fire in the Great Blue Mountains World Heritage Area near the town of Blackheath, Australia, on February 21, 2020. Credit: Brook Mitchell

The authors note that this is the first time researchers have determined how World Heritage forests sequester carbon dioxide in the atmosphere. Over the centuries, World Heritage forests have stored nearly 13 billion tons of carbon, which exceeds the total amount of carbon in Kuwait’s oil reserves.

“We can now see the important role that World Heritage forests play in stabilizing the global climate,” Nancy Harris, director of research at the Global Forest Observatory at the World Resources Institute and co-author of the report, told CNN. “The truth is that we completely underestimate them and underestimate them.”

Most of the places that sequester the most carbon dioxide are in tropical and temperate regions, such as South America and Australia. Although those places Keep sequestering carbonThere are indications that more of them could become carbon sources, the researchers said.

Forest fires, in particular, have burned large areas of these forests in recent years. Although fires are an important part of the forest ecosystem, since many plant species depend on them to disperse their seeds, scientists say they intensify, threatening to release carbon long stored in soil and trees.

A view of a Half Dome from Glacier Point in Yosemite National Park. According to UNESCO, this World Heritage site has become a carbon emitter rather than a sink.

In the past decade, rising temperatures and dry conditions have created much of the environment for wildfires. The report cites several examples of major fires in the past decade at World Heritage sites, including Lake Baikal in Russia in 2016, and in the Tasmanian wilderness and Great Blue Mountains in Australia in 2019 and 2020.

“We’ve seen some wildfires in some places that have emitted more than 30 million tons of carbon dioxide, which is roughly the same as Bolivia’s emissions of fossil fuels in one year,” Resende said.

“A single event can actually match the emissions of an entire country,” he added. “And you have to keep in mind that the emissions accounted for in the study are only within the site limits, meaning they only represent a small portion of the fires in the bigger picture.”

Emerald Pond and Waterfall in Morne Trois Pitons National Park in Dominica.

The report is based on recently published maps that track the global exchange of carbon between forests and the atmosphere over the period 2001-2020, using site-level monitoring to analyze the climatic impacts of forests, as well as the consequences of human activities at these World Heritage sites.

“Our analysis shows how we can stop taking nature for granted and start evaluating the climate benefits that these and other important forests around the world generate,” Harris said.

Forests play a vital role in all societies. According to the International Union for Conservation of Nature, which also contributed to the report, Almost 25% of the world’s populationIn developing countries, they depend to a large extent on forests for their livelihood. In addition, forests contribute up to $100 billion annually in goods and services. It is also home to 80% of the Earth’s biodiversity.

Tourists take pictures of Mount Kinabalu in Malaysia in 2015.

Resende said the ability of forests to prevent the climate crisis from spiraling out of control makes the threats they face even more worrisome.

World leaders will meet in Glasgow, Scotland next week for a party International Climate Negotiations Sponsored by the United Nations, which will try to get countries to commit to continuing to reduce fossil fuels and set a deadline for coal use. They will also discuss stronger commitments to protect and restore the planet’s forests, such as carbon sinks and ending deforestation.

“We hope to really unleash climate action, to protect these gems that are World Heritage sites,” Resende said. “They are laboratories for environmental changes as a whole, related not only to climate but also to biodiversity. We want to facilitate dialogue with key actors to fund and provide some sustainable investments for these sites.”