391 million hectares of world’s tropical forest at high risk of loss: UN report

Tropical forests comprising 391 million of the world’s total 1.6 billion hectares forestland are at high risk of loss, the United Nations Environment Programme (UNEP) said in a new report. These forests sustain 53 million people.

In High-risk forests, high-value returns — Co-benefits assessment for decision-makers, UNEP noted that one in every four people living near pantropical forests — about 53 million residing within 5 km of these forests — depend on forests at high risk of loss.

High-risk forests are areas with high carbon stocks, significant additional ecosystem services and a high likelihood of deforestation. Together they cover about 391 million hectares, an area comparable to the size of the European Union landmass.

Africa accounted for the highest number of forest-proximate people living within 5 km of forests, but the Asia-Pacific has the highest number of forest-proximate people living within 5 km of high-risk forests, UNEP observed.

This number represents the minimum extent of tropical forests needed for protection to achieve the 1 gigatonnes of carbon dioxide-equivalent (GtCO2e) per year emission reduction target while securing co-benefits, according to the report.

Between 1990 and 2019, forests absorbed about 13.1 (± 1.4) GtCO2e anually — around half of global fossil fuel emissions. This highlights the essential role of forest conservation, sustainable management and restoration in climate mitigation, UNEP noted.

Still, tropical forests remain vulnerable to intense pressures from agricultural expansion, infrastructure development, logging and resource extraction. In the past two decades alone, the world lost nearly 10 million hectares of tropical forests every year, an area equivalent to the size of the Republic of Korea, according to the analysis.  

The authors of the report said that protecting these high-risk forests annually become crucial as they provide key ecosystem services such as regulating water resources, improving water quality and preventing soil erosion.

The report highlighted that 10-14 per cent of rainfall is recycled by forests, which allows the rivers to keep flowing, making it available for people, farms and energy needs.

In the Amazon, the rainfall recycling process manifests in so-called flying rivers — vast air currents that transport moisture thousands of kilometres across South America, feeding rainfall as far away as the Andes and agricultural regions of southern Brazil. Disruption of these atmospheric rivers through deforestation directly threatens water security far beyond the forest itself, the report cited.

It underlined that such systems are approaching critical thresholds as deforestation and climate change may weaken this feedback, triggering abrupt ecological transitions.

“In the Amazon, studies suggest that 20-40 per cent deforestation could push parts of the basin past a tipping point, weakening the forest-rainfall feedback and reducing regional precipitation. This could risk large-scale forest dieback and a transition to a savannah state,” UNEP warned in the report.

Each year, these forests retain about 2.3 million tonnes of nitrogen — equivalent to Canada’s annual fertiliser use — preventing harmful nutrient pollution that can trigger algal blooms, kill fish, and contaminate drinking water. They also keep 527 million tonnes of soil and sediment from washing into rivers, the same as filling 150,000 Olympic-size swimming pools with mud, the authors of the report noted, adding the process helps keep rivers clean and protects reservoirs, irrigation canals, and hydropower dams from clogging and damage.

It added that 10 million people received the equivalent of their annual nutrition from crops that are dependent on pollinators from the high-risk forests.

Further, 111 million tonnes of fuelwood every year in addition to the fruits, nuts, fibres and medicinal plants that millions of people depend on, come from these tropical forests. “These resources meet the basic energy, food and income needs of about 25 million materially poor people. Women and Indigenous Peoples, in particular, depend on these resources for household cooking, heating and nutrition, as well as for local trade and cultural practices,” the report said.

These forests also prevent loss of GDP of $81 billion, thus protecting from natural hazards by stabilising soils, slowing water runoff and buffering extreme weather events, high-risk forests reduce the risks of floods, landslides and storms, the report noted.

Protecting these areas prevents about 527 million tonnes of soil and sediment from washing into rivers each year, equivalent to filling 150,000 Olympic-size swimming pools with mud. This keeps rivers clean and protects downstream infrastructure, the authors said.

It observed that such protection prevents an estimated $81 billion in annual GDP losses by avoiding damage to roads, bridges, homes, farmland, and other infrastructure — safeguarding both lives and national economies.