According to a joint investigation by the Guardian newspaper and the nonprofit climate watchdog, Corporate Accountability has questioned the efficacy of the “vast majority” of environmental projects most commonly used within the voluntary carbon market.

The analysis was first reported last week by the trade website Power Technology. 

Such projects aim to offset greenhouse gas emissions by finding endeavors with low enough carbon footprints to bring into equilibrium carbon produced by manufacturers. Still, the report says the “fundamental failings” cannot be relied upon to tackle global warming, the report claims.

The investigation analyzed 50 emission offset projects that have sold the most carbon credits within the global VCM, and found most of them “…exaggerate climate benefits and underestimate the potential harm caused by the project’s activity.”

The most prevalent projects cited in the report 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 Guardian and Corporate Accountability data come from Allied Offsets, the world’s most extensive and comprehensive emissions trading database, aggregating information about projects traded within the VCM from their inception.

The analysis found that 78% of the 50 projects, or 39 of the 50 companies analyzed, were categorized as “likely junk or worthless” due to one or more “fundamental failing” undermining its alleged emissions offsetting power.

Eight others, or 16%, look “problematic”; evidence suggests they may have at least one fundamental failing and could therefore be “junk.”

The analysis also found that $1.16b worth of carbon credits have been traded so far from those projects classified as “likely junk or worthless,” the report claims.

The criteria for assessing whether a project is likely junk was based on whether there was “compelling evidence” or high risk that the project could not guarantee additional GHG emission cuts. In some cases, there was evidence to suggest that projects were leaking further, additional emissions, or simply shifting emissions elsewhere. Evidence suggested that a project’s climate benefits had been exaggerated in other cases.

In January, a joint investigation by the Guardian, the German newspaper Die Zeit and online climate reporters at SourceMaterial revealed that more than 90% of rainforest offsets offered by Verra, the world’s leading carbon credits certifier, were likely to be “phantom credits” and did not represent genuine emissions reductions.

Verra published a statement on September 21 in response to the latest Guardian and Corporate Accountability investigation, suggesting that the Guardian has gone “dangerously off track when it comes to reporting on the VCM.”