Unprecedented wildfires raged across Russia in 2021, burning vast swaths of forest, sending smoke as far as the North Pole and unleashing astounding amounts of greenhouse gases into the atmosphere.

Logging operations continued. Insect infestations wreaked havoc. The relentless expansion of agriculture, meanwhile, fueled the disappearance of critical tropical forests in Brazil and elsewhere at a rate of 10 soccer fields a minute.

Around the globe, 2021 brought more devastating losses for the world’s forests, according to a satellite-based survey by the University of Maryland and Global Forest Watch. Earth saw more than 97,500 square miles of tree cover vanish last year, an area roughly the size of Oregon.

“When we lose forests, it’s kind of like locking in emissions,” said Stephanie Roe, lead global climate scientist for the World Wildlife Fund, comparing it to building a coal plant that will emit planet-warming pollutants for decades. Roe was not involved in the Global Forest Watch analysis.

The latest findings include silver linings, however modest.

The recent figures represent a 2 percent decline compared with losses in 2020, researchers said. And in some places, such as Indonesia and Malaysia, loss of primary forests – defined as mature, native forests undisturbed in recent history – has continued to wane in recent years.
In addition, not all the losses represent permanent deforestation, especially outside the tropics.

Many of the areas that vanished in 2021, such as the boreal forests dominated by hardy spruce and pine that were burned by wildfires in Canada, Russia and the United States, are expected to grow back over time – though perhaps not soon enough to aid the world in its efforts to pull as much carbon from the atmosphere as possible.

Forested plots cut down in managed tree plantations also do not necessarily result in permanent losses.

But the latest data hardly offers cause for celebration.

Russia experienced its “worst fire season ever,” said Elizabeth Goldman, a researcher with the World Resources Institute (WRI), which launched the Global Forest Watch project 25 years ago. While such blazes are a natural part of the boreal ecosystem, “the Russian fires are particularly worrying because of Siberia’s vast peatland area and melting permafrost, both of which can release massive amounts of stored carbon when peat is dried or burned, or when permafrost melts,” she said.

This can result in feedback loops that can worsen fires and hasten climate change.

There are signs that the problem might get worse. In a recent assessment, the Intergovernmental Panel on Climate Change found that human-caused emissions have significantly increased the area burned by wildfires the American West and British Columbia.

Fires have scorched growing areas in the Amazon, the Arctic, Australia and parts of Africa and Asia, the authors found. And wildfires now generate up as much as a third of all carbon emissions from the world’s forests and landscapes.

Already this spring, meanwhile, wildfires have appeared on the peatlands of Russia’s Far East and elsewhere, and the country’s federal forestry agency reported that it extinguished more than 600 fires over roughly 91,000 acres last week.

Meanwhile, in places such as Bolivia and parts of the Brazilian Amazon, the destruction of forests to make way for livestock and crops such as soy could mean more lasting losses that carry serious implications not only for the climate, but also for biodiversity.

It is these forests in the tropics, researchers say, that have experienced “stubbornly consistent” losses in recent years.

“They are really critical when it comes to the climate story,” Roe said of tropical forests.

Hopeful case studies do exist.

Last year marked Indonesia’s fifth year in a row of declining forest loss, after the government announced in 2016 a moratorium on all activities that could damage the nation’s primary forests and peat-filled wetlands.

“Corporate commitments and government actions are clearly working,” said Hidayah Hamzah, a research analyst at WRI.

The precarious state of the world’s forests underscores an essential challenge as its tries to combat climate change.

To slow Earth’s warming, humans will need a huge helping hand from the world’s land — in particular its forests, which soak up large amounts of carbon dioxide each year. But as wildfires burn, insect infestations take their toll and wetlands are drained for agriculture, the land can become yet another source of greenhouse gas emissions.

If forests continue to wither, so will the likelihood that Earth’s warming can be limited to 2.7 degrees Fahrenheit compared with preindustrial levels – a central aim of the Paris climate accord.

Since a key U.N. climate summit in Glasgow last fall, at least 140 countries have committed to collectively halt and reverse deforestation by the end of this decade. Thursday’s analysis shows what a monumental challenge that will be.

It’s a lofty goal – and a short timeline.

“We’ve got 20 years of data now showing the persistent annual loss of millions of hectares of primary tropical forest alone,” said Frances Seymour, a distinguished senior fellow at WRI. “But we don’t run out of fingers counting the number of years we have to bring those numbers down to zero.”

“Those actions,” Seymour said, “are going to have to be dramatic.”