Choosing Carbon Projects Built to Last
Our mission at OffsetC is to build trust and confidence in carbon credits. We explain how they work and which attributes we use to determine their quality and efficacy. In the last post, we emphasized that every carbon credit possesses attributes that: (1) indicate whether purchasing that credit is a good value and (2) whether it will meet our planet’s urgent needs for carbon reduction.
While the definition of quality varies somewhat, everyone agrees on three attributes that a high-quality (a.k.a. high-integrity) carbon credit must address: time, money, and information. In this post, we focus on the role of time.
Lock it away: Durability and Permanence
To be considered high quality, credits must be ‘durable’ or ‘permanent.’ Whatever activity the project engages in, it must result in carbon removal or avoidance that lasts a long time. A high-quality credit offsets carbon longer than the lifetime of carbon dioxide in the atmosphere, typically about 100 years. Credits with low durability re-emit the carbon before the reductions have an appreciable impact. They are not effective in halting climate change.
OffsetC offers projects projected to have durability greater than 100 years. In some cases, they’re projected to last more than 1,000 years. These long time scales give humanity much-needed runway to develop technologies and implement policies for a carbon-sustainable future.
Durability encompasses various natural and human risks to the longevity of a project’s carbon reductions. Some newer technologies, like direct air capture or enhanced rock weathering, chemically transform carbon dioxide into solid form and store it underground for hundreds to thousands of years. They are highly durable.
Don’t Get Burned
Conversely, sometimes projects we feel good about, like planting trees, may be at risk from processes that undo their carbon benefits, like wildfires or illegal logging. Those events re-emit sequestered carbon into the atmosphere, making such projects significantly less durable.
Beyond the project type, carbon credit durability is also driven by project specifics and context. Consider two reforestation projects. One is on the US west coast and faces mounting risk of wildfire. The other project is in the US southeast where wildfire is rare. All else being equal, the second project would have higher durability, because in any given year there is a lower probability that it will suffer a wildfire.
Depending on the project type, assessments of durability may need to be updated as climate change and local conditions evolve. Generally, however, projects that stably store carbon (e.g. deep underground) or remove potent greenhouse gasses (e.g. methane mitigation) have high durability.
To learn how well a project spends its money to achieve its carbon reduction targets, read our next post on ‘additionality’.
Heard enough and want to start taking climate action by offsetting your fuel purchases? Join our carbon crusade!
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Our Understanding Carbon Offsets Series:
Part 2: Choosing Carbon Projects Built to Last
Part 4: Trust, but Verify
Part 5: Beyond Carbon: Do Good, Not Harm
