Why scientists say Canada's logging industry produces far more emissions than tallied

Canada's forestry sector is responsible for far more greenhouse gas emissions than show up in official tallies, potentially leading to policies that aren't in line with the country's climate goals, a new study suggests.

The peer-reviewed study, published in the academic journal Frontiers in Forests and Global Change, found that annual greenhouse gas emissions attributable to forestry between 2005 and 2021 were, on average, nearly 91 million tonnes of carbon dioxide equivalent which would put the sector on par with emissions from the agricultural sector.

By contrast, Canada's official inventory report shows the forestry sector acting as a carbon sink, which means it absorbs more carbon from the air than it sends into the atmosphere. The report has the sector absorbing an average of five million tonnes of carbon dioxide equivalent annually over the same period.

Canada's forest can be viewed as a natural way of regulating carbon emissions. Roughly two-thirds of the country's forested area is defined as "managed," which includes areas where wood is harvested.

As trees grow, they draw carbon from the atmosphere into their leaves, trunks and down into their roots and soil. But when trees die, whether from logging, wildfire, or otherwise, some of their carbon is eventually lost into the atmosphere as the wood is burned or decomposes.

The debate over how much carbon is being absorbed or lost by Canada's forestry sector comes down to the way the federal government does its emissions accounting, said Anthony Taylor, an associate professor of forest management at the University of New Brunswick and one of the study's co-authors.

"Forests are often claimed to be a natural climate solution," Taylor said in an interview from his office in Fredericton.

"But studies like the one we just published here, they begin to identify, is that really the case? Can we really use our forest to offset other sectors if indeed they may be a net source of carbon rather than a net sink, which is what's currently portrayed?"

According to the study's authors, the underreporting of emissions from the forestry sector comes from failing to account for all the carbon emissions associated with managed forests.

In particular, the government doesn't count the emissions from things like insect outbreaks and wildfires (which produced a record amount of emissions last summer) as part of the forestry sector's total.

However, once those forests grow back and reach an age of commercial maturity, the government designates the carbon they absorb to the forestry sector.

The "inclusion of that sink is what's causing the biggest difference between what Canada is currently reporting as the emissions from the forestry sector versus what we found in this study," Taylor said.

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Growing criticism

The study adds to a growing body of research and reports calling into question the way forestry sector emissions are calculated, and the way the industry is managed.

A report last year from the Commissioner of the Environment and Sustainable Development, an independent government watchdog within the auditor general's office, found the federal government "did not provide a full and transparent picture of how Canada's forests remove carbon from the atmosphere or contribute carbon to it."

A recent analysis by Nature Canada, which advocates for protection of endangered species and habitats, argued forestry was responsible for more than 10 per cent of Canada's total planet-heating emissions.

In a statement, Environment and Climate Change Canada said the reporting categories and emission sources presented in its annual inventory report are based on guidelines from the Intergovernmental Panel on Climate Change (IPCC).

"These methodologies are built on authoritative information that is accepted by subject matter experts and based on mature science," said Cecelia Parsons, a ministry spokesperson.

Parsons said the federal inventory report includes all processes involved in "forest management, from forest inventories to forest harvest for the production of wood products."

A spokesperson for the Forest Products Association of Canada, an industry group, said it didn't have time to review the study in detail, but stressed that overall "Canada's forest sector remains committed to supporting Canada's greenhouse gas emissions reduction targets" and sustainable harvesting practices.

A global issue

Tim Searchinger, a senior research scholar at Princeton's Center for Policy Research on Energy and the Environment, reviewed the study for CBC News.

He said it's among a number of studies that show countries around the world are underreporting logging emissions.

He was co-author of a recent study published in the scientific journal Nature that estimated global wood harvests will add 3.5 to 4.2 billion metric tons of greenhouse gases to the atmosphere annually over the coming decades.

That amounts to roughly 10 per cent of recent annual emissions of carbon dioxide, and more than three times the annual emissions from aviation.

Searchinger has argued many assessments of timber or paper production wrongly treat the harvest of wood as having no effect on the climate as being "carbon neutral" so long as the harvest is sustainable.

That assessment, he explained, ignores the reality that if new wood harvests didn't occur, forests would continue growing and take more carbon out of the air.

In an interview, Searchinger likened this to the flawed logic of someone saying, "I'm just going to steal some money out of your pension, but don't worry about it. I'm only going to take out the amount that you put in this year. So you're not going to be any poorer."

Better management needed, author says

In Canada, Taylor and his co-authors say stricter government policies are needed to reduce logging emissions, through longer harvest rotations, protection of older forests and reducing the production of short-lived forest products.

"The most straightforward way through which our forest can improve our ability to sequester carbon would be to reduce deforestation," he said.