Canada’s explosive wildfire season has already pumped millions of tons of carbon dioxide into the atmosphere. Some of that carbon is coming from vegetation burned at a carbon offset project, highlighting the fragility of a tool the world is relying on to fight catastrophic climate change.

With Canada facing what’s on track to be its worst wildfire season on record — and climate change fueling ever more destructive blazes — climate experts and offset developers are concerned it could be a harbinger of what’s to come.

On June 3, British Columbia fire officials spotted a blaze that has impacted the BigCoast Forest Climate Initiative project, according to Domenico Iannidinardo, senior vice president for forests and climate at Mosaic Forest Management Corporation, which runs the project.

“About 100 hectares of our 40,000 hectare project was involved in this fire,” or about 0.25% of the project, Iannidinardo told Bloomberg Green. That’s an area equivalent to roughly 140 football pitches worth of forest.

So far, little is known about how the fire will impact BigCoast’s carbon removal capacity or how much carbon has been released. Werner Kurz, senior research scientist in the Canadian Forest Service, said its emissions could be up to 32,250 tons of carbon dioxide equivalent, depending on the fire’s severity. The impact is “clearly not trivial” for BigCoast or the local area, he said, but it’s a “rounding error” in terms of the climate impact of the wildfires that have ravaged the province.

As of June 23, crews had suppressed the fire so it was no longer spreading. Mosaic said that assessing the emissions from the area that was burned “will take some time.” They will be incorporated into future carbon accounting and be independently verified. Still, Iannidinardo described the “disturbance” as “negligible.”

Companies and countries are increasingly relying on carbon offsets to reach their emissions targets, a tool used in an attempt to compensate for their climate pollution by investing in projects that reduce or remove emissions elsewhere. But climate scientists and activists say the instruments, including those based on forests, aren’t generally effective at mitigating climate change, despite decades of experimentation and improvement. They point to forest fires — which are increasing in severity partly due to climate change — as a big reason why. Grayson Badgley, research scientist at CarbonPlan, a US-based non-profit, said it’s a “risky bet” to count on trees — temporary stores of carbon — to compensate for the carbon dioxide released by burning fossil fuels that stays in the atmosphere for centuries.

In 2018, Mosaic, a logging company, and its partners committed to stop cutting down trees in the project area and instead protect them for 30 years. The company is measuring the tons of additional CO2 stored and the forestry-related emissions avoided, and packaging each of those as a carbon credit for sale to companies or individuals looking to offset their carbon footprint. Each credit represents one ton of CO2 removed or not added to the atmosphere.

The project has already issued 1.4 million credits, an amount equivalent to the total emissions of Sierra Leone in 2021. They’ve been bought by UK-based AI company Dataiku, global insurance firm Aspen and the American Institute for Foreign Study, a travel and insurance company, among others, according to Bloomberg Green analysis of public data. There’s currently no information to indicate any of those companies’ credits have been impacted by this year’s fire.

Under the rules of the offset registry Verra, whose standard Mosaic uses, the company has 30 days to report any damage to its forests and up to two years to submit a “loss report” detailing its impact. As a type of insurance mechanism against wildfires and other risks, project developers must contribute a portion of their credits to what’s known as a buffer pool. If disaster strikes and impacts a project’s carbon inventory, the standard states that an equivalent number of credits are taken out of the pool.

BigCoast’s buffer pool is 15.5% of its issued credits, Mosaic said. But none of these are earmarked for natural risks like extreme weather, pest outbreaks and fire, according to project documentation. That’s because the company evaluates that risk — calculated according to a matrix of significance and likelihood — to be zero.

That assessment is “mind-boggling,” said William Anderegg, director of the Wilkes Center for Climate Science and Policy at the University of Utah. Fires are a “really dramatic risk” that forest offset projects face, he said, along with other risks such as drought stress and insect outbreaks.

Mosaic said its risk assessment is based on the fact that “the project is geographically and ecologically diverse and distributed,” meaning the likelihood of widespread damage due to fires or something else measures as “insignificant.”

Under Verra’s rules, credits allocated against other risks can backstop a fire incident, but in the long run this could have a serious impact on the insurance efficacy, Anderegg said. If wildfires eat up more than was budgeted, that has “very real impacts on whether these projects are likely to succeed over a century,” he said.

A team of researchers led by Barbara Haya at the University of California, Berkeley’s Goldman School of Public Policy recently identified a set of shortcomings in carbon offset registry methods, like those used by BigCoast, that could “critically undermine” their buffer pool policies. None take into account how climate change may increase fire risk, for example. In the US, CarbonPlan’s Badgley and a team of researchers found California’s buffer pool to be “severely undercapitalized.”

Verra relies on “the historical likelihood of an event occurring” to guide its buffer pool policies, said company spokesperson Joel Finkelstein. The company is set to update its insurance tool later in the summer to better account for changing risks due to climate change.

Canadian offset developers across the country are nervous about the rest of the fire season. “This is a wake-up call,” said André Gravel, chief executive of Société de gestion d’actifs forestiers (Solifor), which runs the Monet Forest Conservation Project. “The frequency of fires is increasing,” he said.

“Everyone is very concerned and on high alert,” said Adrian Leslie, manager of a Nature Conservancy of Canada forestry offsets project called Darkwoods in British Columbia. The group said approximately 4,485 hectares of the project burned in 2021, or less than 10% of the total area. That equates to about 36,700 tonnes of CO2 being released, according to a preliminary estimate shared by Leslie.

“The IPCC has made it very clear that every ton matters, every year matters, every degree matters,” Kurz said. Wildfire risk is increasing and project developers must recognize and address this: “We have to bend the curve.”

--With assistance from Demetrios Pogkas.