Carbon offsets can support genuine greenhouse gas reductions or removals, but their effectiveness depends on the quality of the carbon credits used. Not all carbon credits provide the same level of assurance that the claimed emissions reduction or removal is additional, accurately measured and likely to last.
A credible carbon credit should represent an emission reduction or removal that would not otherwise have occurred. This is known as additionality. Other important considerations include how accurately the carbon saving has been calculated, whether the benefit will be maintained over time and whether the same reduction could be counted more than once.
There is evidence that some carbon credit projects have overstated their climate benefit. A 2024 systematic assessment published in Nature Communications examined 2,346 projects across several project types and found substantial differences between the number of credits issued and the reductions independently estimated to have occurred. The research did not assess every type of carbon project, so its findings should not be applied equally to every credit available on the market.
Carbon offsets should therefore be assessed carefully and used alongside a credible emissions reduction strategy rather than as a replacement for reducing a business’s own emissions. This is also the approach recommended in the UK Government’s voluntary carbon market integrity principles.
