Planet-warming emissions released by CanadaSA国际影视传媒檚 record-breaking 2023 wildfires were quadruple the countrySA国际影视传媒檚 fossil fuel emissions for the previous year, and were surpassed only by the three most high-emitting countries, a new NASA study has found.

The study published Wednesday in the journal Nature says only China, India and the United States release more carbon per year than CanadaSA国际影视传媒檚 2023 wildfires did from May to September.

Lead author Brendan Byrne called the results SA国际影视传媒減retty shocking,SA国际影视传媒� and said they raised concerns about whether CanadaSA国际影视传媒檚 boreal forest can be relied on in the future to absorb more carbon than it emits.

SA国际影视传媒淭hereSA国际影视传媒檚 a concern that the more frequent fires could really limit the ability of the forest to take up carbon,SA国际影视传媒� said Byrne, a carbon cycle scientist at NASASA国际影视传媒檚 Jet Propulsion Laboratory in California.

The study says extreme hot and dry conditions helped drive wildfires that burned through four per cent of CanadaSA国际影视传媒檚 forest area and led to the evacuation of 232,000 people.

Climate models project that those conditions may become normal by mid-century and lead to increased fire activity.

That raises questions about one of humanitySA国际影视传媒檚 important allies in the fight to slow climate change.

CanadaSA国际影视传媒檚 forests have long absorbed more carbon than they release and forests around the world are thought to absorb about 25 per cent of human-caused emissions. Increased fire activity, however, SA国际影视传媒渨ill reduce the capacity of these Canadian forests to continue to act as a carbon sink,SA国际影视传媒� the study says.

Any reduction will then have to be reflected in global climate targets to limit global warming, Byrne said.

SA国际影视传媒淚f those ecosystems start releasing carbon, thatSA国际影视传媒檚 not something you really account for and itSA国际影视传媒檚 not something that gets picked up in the Paris AgreementSA国际影视传媒檚 commitments to reduce emissions,SA国际影视传媒� Byrne said.

How Canada accounts for wildfire emissions has drawn the ire of environmental groups in recent years.

The study notes Canada does not count wildfire emissions toward its national greenhouse gas emissions, a decision that differs from United Nations guidelines. Those guidelines suggest countries should treat all carbon emissions on managed lands as human caused.

Instead, Canada treats wildfires as natural disturbances.

Environmental groups have argued that accounting obfuscates the forestry industrySA国际影视传媒檚 climate impact. It is not charged with wildfire emissions but gets credited for emissions absorbed by forests once they are old enough to be harvested, even if they grew back after wildfires, the groups have argued.

Natural Resources Canada has said its forest sector reporting is backed by continuous scientific consultation and review.

In a shift this year, CanadaSA国际影视传媒檚 greenhouse gas inventory report to the United Nations did for the first time report that the forestry sector had been emitting more carbon than it absorbs. The government said the revised number was based off new estimates that showed the logging industry had harvested a smaller area than assumed before 1990.

Nature Canada, an environmental charity, has called the shift SA国际影视传媒渕eaningful,SA国际影视传媒� but said it still underreported emissions.