In recent years, record numbers of corporate and public entities have set individual net-zero emissions targets for varying completion dates, with the vast majority relying on voluntary carbon offsets to neutralize some of their emissions.
The logic of offsets implies that the polluter pays someone else to reduce their emissions, leading to a reduction in overall emissions. Offsets are very appealing to companies when their costs are lower than the cost of the company reducing its own emissions.
In principle, offsets can be a great tool to monetise ecosystem services. The co-benefits some of them offer, such as biodiversity conservation, poverty alleviation and local community support, can be substantial. However, carbon offsets are currently nearly all emissions avoidances, with the majority generated from the forestry and land-use sector, with only a tiny supply of long term carbon removals, and it will likely take years to develop scalable and affordable production of such removals.
The different tech and nature-based carbon removal solutions were discussed by a panel of experts from academia and industry at an Innovation Showcase event during COP26, hosted by Edinburgh Innovations.
Subsequent to this, at another event hosted by EI called AIMday, Adrian Smith from Ecometrica put forward a question about offset comparison. He wanted to know if there is a link between the price of voluntary offset credits and the permanence of the carbon storage methods. This led to a project funded by EPSRC IAA to compare the cost and durability of carbon dioxide abatement.
Beatrice Mocci’s research confirmed that the more the offset costs, the more permanent the carbon solution: there is a very strong correlation between cost and durability. For example, restoring and/or avoiding the loss of forestation is one of the most popular carbon abatement options as it is relatively cheap – but it is also not very durable.
Another University of Edinburgh research by Jana Schebera  has found that the few existing long term carbon removal options such as Climeworks (which performs direct air capture and solidifies CO2 for long term storage) cost several orders of magnitude more than emissions avoidances. Currently, 1 tonne of CO2e at Climeworks sells at over $1,000, whereas the average wholesale price of carbon offsets certified by the well-established registries was well below $10 per CO2te.
Jana concludes that companies and public entities must focus as much on bringing down their own emissions as relying on carbon offsets to reach net-zero.
Understanding where and how different carbon offsets are created, and how their storage security is verified and monitored (as part of the business drive to net-zero) is a great example of geosciences research and is a strong selling point for the Edinburgh Climate Change Institute (ECCI) when approaching industry partners.
Indeed, there has been considerable interest from leading players in sectors such as geothermal, hydrogen, biochar, and space (for monitoring and verification). Such businesses are keen to work with the geosciences expertise at the University covering various tech and nature-based solutions.
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 Beatrice Mocci, a former MSc carbon management student, was commissioned to research and compare different CDR options.
 Edited from MSc dissertation by Jana Schebera Supervisors: Dr Frances Warren and Clare Wharmby.
Image: Aiokr Chen/Unsplash