New Scientist: Carbon offsets are one of the five worst ideas of the 21st century

Along with Bitcoin, Social media, Alternative fuels, and Effective altruism.

PHOTO Credit: Chris Lang.

“They offered so much promise, but ultimately turned sour,” New Scientist writes. “These are the most disappointing ideas since the turn of the millennium.” One of these ideas is carbon offsets.

Michael Le Page, who has been a journalist with New Scientist for the past 11 years writes that offsetting “sounds like such a simple idea”. A polluting corporation can offset its emissions by buying carbon offsets from projects that reduce or avoid CO₂ emissions, or remove CO₂ from the atmosphere. The hope is that the offsetting project cancels out the corporation’s emissions.

Except, of course, that rarely happens in reality. And I would disagree that carbon offsets ever offered any promise, apart from to the fossil industry, which saw offsets as a way of continuing to profit from business as usual for as long as possible.

Le Page runs through the fundamental structural problems inherent in all carbon offsets:

• Counterfactual baselines: Offset projects are based on a story about what would have happened in the absence of the project. Obviously, when the project goes ahead, there is no way of proving what would have happened. Le Page gives the example of a plot of land that is planted with trees. Carbon offsets are sold based on how much carbon the trees removed from the atmosphere. The assumption is that no trees would grow without the reforestation project. But it is possible that trees could have naturally regrown, resulting in a more biodiverse forest than a plantation. A biodiverse forest is more resistant to droughts and diseases than a monoculture plantation. The result of the tree planting is more CO₂ in the atmosphere, not less.

• Additionality: Carbon offsets can only be issued to projects that would not have happened without the carbon finance. “This is easy to fake,” Le Page points out. Professor Myles Allen at the University of Oxford tells Le Page that, “With a good enough accountant, there seem to be unlimited ways of proving additionality.”

• Exaggerated benefits: Many offsets are based on avoided emissions by protecting forests — REDD projects. A long list of academic papers, investigative journalism, and NGO reports in recent years has exposed the fact that many of these projects have exaggerated the number of carbon credits generated. “And that can have real consequences,” Le Page writes. “People might, say, take more flights because they think their emissions are being offset, when that is far from the case.”

• Alternative to investing in greener tech: Instead of investing in cleaner technology, corporations can continue polluting while buying carbon offsets and claiming to be addressing the climate crisis.

• Permanence: Particularly with nature-based offsets there is no way of guaranteeing that the carbon will remain stored for as long as needed. When fossil fuels are burned, some of the CO₂ remains in the atmosphere for a very long time. “A CO₂ storage period of less than 1,000 years is insufficient for neutralising remaining fossil CO₂ emissions,” according to a 2024 paper published in Nature. Trees can be killed by wildfire, drought, or disease — all of which are getting worse as the climate crisis intensifies.

Le Page ends by referring to the Oxford Offsetting Principles, developed by Myles Allen and colleagues. The first two words of the Principles are the most important: “Cut emissions”.

A brief history of offsetting

To be pedantic, carbon offsets raised their ugly heads well before the 21st century. Back in 1977, Freeman Dyson, a theoretical physicist and mathematician, decided that it should be possible “to plant enough trees and other fast-growing plants to absorb the excess CO₂ and bring the annual increase to a halt.”

Carbon Brief goes back even further in its 60-year history of carbon offsets to 1960 and Ronald H Coase’s paper, “The Problem of Social Cost”.

The first land-based carbon offset scheme was in 1988. A tree planting scheme in Guatemala was supposed to offset the emissions from a new coal-fired power plant in the USA. Mark Trexler, who was hired by the World Resources Institute to oversee the project told Carbon Brief that,

“No one ever thought that carbon offsets were going to save the world. That just wasn’t the way we were thinking about this. We were thinking: this is an interim measure until public policy gets going. It was a way of getting the conversation started. No one then thought that we would be doing offsets 35 years later.”