The investigation analysed the top 50 emission offset projects, selected because they have sold the most carbon credits within the global VCM, and found that most of them exaggerate climate benefits and underestimate the potential harm caused by the project's activity.

The most popular projects traded globally include forestry schemes, hydroelectric dams, solar and wind farms, waste disposal and greener household appliance schemes across 20 countries, most of which have developing economies. The data comes from Allied Offsets, the world's biggest and most comprehensive emissions trading database, which aggregates information about projects traded within the VCM from their inception.

The analysis found that 39, or 78%, of the 50 projects were categorised as "likely junk or worthless" due to one or more "fundamental failing" that undermines its alleged emissions offsetting power.

Eight others, or 16%, look "problematic". There is evidence to suggest that they may have at least one fundamental failing and could therefore be "junk".