Fortune 500 companies have significantly undercounted their GHG emissions

The Fortune 500 companies that account for roughly 27% of greenhouse gas emissions have significantly undercounted their contributions to global warming, according to a report from the carbon offset and monitoring firm Recapture.

Actual reported emissions from Fortune 500 companies equaled about 8.04 billion tonnes of carbon dioxide equivalent in 2018 and 7.56 billion tonnes of carbon dioxide equivalent for 2019. But over that period, Recapture estimated the true footprint of these firms to have been roughly 13.34 billion tonnes of CO2e in 2018 and 13.15 billion tonnes in 2019.

According to the Recapture study, the variation between estimated emissions and what companies reported was in part thanks to the inconsistent ways in which carbon measurements are obtained. The problem becomes especially apparent with corporate estimates of their Scope 3 emissions (the emissions that come from customers' use of a company's products or services).

For instance, in ExxonMobil's laughable public relations stunt of an announcement around its commitment to reduce its carbon footprint the company neglected to account for Scope 3 emissions in its statement.

"ExxonMobil's emissions reduction pledge misses the mark and is too little, too late," Kathy Mulvey, accountability campaign director in the Climate and Energy program at the nonprofit Union of Concerned Scientists, told ABC News in a statement. "This commitment solely covers operational emissions, known as scope 1 and 2, which make up only a small portion of the global warming emissions associated with a fossil fuel company's business."

"By not making any commitment to reduce the emissions that come from burning oil and gas, known as scope 3, ExxonMobil is shifting blame for the bulk of its emissions onto consumers who are using its products exactly as the company intended," Mulvey told ABC.

Beyond the discrepancies in reporting standards and the variability that causes in corporate numbers, these companies are also engaged in a shell game with consumers and stakeholders, the report from Recapture found.

In fact, emission footprint disclosures to stakeholders often cite lower volumes of emissions than these companies report to the CDP, a non-profit organization that tracks carbon footprints and offset data for companies and their investors.

And as companies increasingly turn to voluntary carbon removal credits to reach their net zero goals in the short term, they're going to find that there's not enough supply to meet their growing demand.

That's setting aside the fact that many advocates now believe that most carbon offsets are problematic at best.

"[Many] of the carbon credits given out in both the voluntary and offset markets in the past have not led to a change in emissions. For example, as much as 80 percent of the California forest offset credits failed an additionality test because most of the alleged additional carbon being stored was going to be stored with or without credits," wrote the authors of a recent opinion piece in the Yale School of. the Environment publication, Environment360. " If this poor performance continues, offset and voluntary markets will remain ineffective. If the money being spent on offsets and voluntary credits would otherwise have been spent on actual mitigation, the markets would actually be reducing mitigation, not increasing it."

What's missing, the study's authors conclude is an emphasis on renewable energy deployment and carbon removal in the offset market.

"Governmental regulation and centralized oversight is likely required to ensure emission reporting, carbon removal, an appropriately incentivized carbon market, and the development of other climate solutions accelerate on schedule with science-based targets," according to the study.