The devastating wildfires scorching California point to the perils of relying on tree planting for carbon offsets when there’s a risk that the investment will literally go up in smoke, Carbon Market Watch argues in an opinion piece published last month.
“Companies are increasingly adopting ‘climate-neutrality’ targets, which often include relying on forests to compensate for pollution,” writes Policy Officer Gilles Dufrasne. But “after yet another such offset project was swallowed by flames in California, unresolved questions about forest and land offsets resurface.”
Dufrasne’s assessment points to a list of problems with land-based offsets, beginning with confirming that the trees wouldn’t have been planted without the offset program, and ensuring that emissions are actually reduced, not just shifted to another location.
But the risk with forest offsets, brought into focus by the U.S. wildfire season in California and elsewhere, is that “any emissions absorbed and stored by a tree could be released after a very short amount of time” when it burns.
“Trees store carbon and use it to grow,” Dufrasne explains. “When a tree dies, the carbon is released back into the atmosphere. For a polluting activity (by a company, country, or an individual) to be carbon-neutral, in theory, the tree should store the carbon for at least as long as the emitted greenhouse gases stay in the atmosphere. This can take several millennia, but it is often assumed, for simplicity, that carbon remains in the atmosphere for 100 years.”
Forest offset providers often set aside “buffer pools” of trees as a form of insurance against wildfire—they’re planted as back-ups, with no carbon credits attached to them, then brought into the offset scheme if other trees die. The question is whether the approach works in the real world, and “the simple answer is that nobody knows. Advocates of this strategy, implemented by all major voluntary programs, point to the fact that there have always been enough of these credits to balance the few reversal events which have occurred until now.”
But with only 11 years of experience for the longest-standing forest offset program, “no buffer has yet existed for long enough to face a very significant amount of risk—and the warming climate will increase those risks,” Dufrasne writes. “Stating today that buffers are effective is like purchasing fire insurance for your house, and after 10 years declaring that the insurance is working because the house is still standing.”
The experience in California and elsewhere raises a series of questions, he says:
• Whether enough credits have been set aside;
• Whether an offset meant to run 10 to 40 years offers enough “permanence” in a system that is supposed to run at least 100;
• Whether the trees will be lost after the offset monitoring period has ended—in which case the carbon they store would enter the atmosphere, with no accounting system in place to take notice [If a tree burns in the wilderness…?—Ed.].
The question, Dufrasne says, is whether a forest offset is still better than nothing. “Actually, it might not be,” he writes. “Protecting forests requires finance and should be a top climate policy priority.” But “when a company finances a forestry offset project, it is not financing an emissions reduction/removal. It is financing an emission postponement, temporary storage of carbon. Claiming carbon neutrality is therefore inaccurate. Credits should at most be temporary and expire after a certain number of years,” as they did under a past United Nations carbon market, the Clean Development Mechanism.