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.