One of the biggest holes in the carbon rulebook was plugged last week when the Greenhouse Gas Protocol finalized its standard for land-sector emissions and removals. 

The 133-page document, which was five years in the making, has implications for companies in food, agriculture, apparel and other industries. The new rules are being widely hailed as a welcome step forward, but they are also generating questions about how they will work in practice.

The protocol’s Land Sector and Removals Standard details accounting rules for the many scenarios by which land-sector activities generate and remove greenhouse gases — from emissions in bovine burps and tractor tailpipes to carbon-capture by soil microbes, crops and trees. Overseen by the protocol’s backers, the World Resources Institute and the World Business Council for Sustainable Development, it received input from more than 300 external reviewers.

Uncertainty about how to account for these processes in emissions disclosures has been blamed for limiting investment in projects that reduce land-sector emissions. “This is not just a standard, this is a catalyst for transformation the sector urgently needs,” said Christopher Schwarz, associate director for implementation at South Pole, a consultancy.

More flexible accounting — to a point

Identifying precisely where the wheat in your breakfast cereal was harvested is often all but impossible; like many other ingredients, it is aggregated from multiple farms during processing. This makes it difficult for buyers to claim the benefits of supporting suppliers that cut fertilizer use or take other emissions-reduction measures.

The new standard helps by giving the green light to an approach known as “mass balance.” This allows conventional and low-carbon crops to be mixed in supply chains, provided the emissions savings are claimed by an appropriate proportion of the resulting products. The approach, which was not included in the previous draft of the standard, provides welcome flexibility, particularly because it allows for mixing across sites in a supply chain, said Alice Chang, senior manager for sustainability standards at Indigo, a sustainable agriculture company.

Yet the protocol stopped short of including an even more flexible accounting mechanism, known as “book and claim,” in which the environmental benefits associated with an ingredient can be traded independently of the ingredient itself. Advocates for such market-based mechanisms emphasize that integration with existing standards, including the protocol, is essential to the success of the approach. Another important standard-setter, the Science Based Targets initiative, opened the door to these mechanisms in a recent update.

The decision will likely not be the final word from the protocol on the debate, however. A separate workstream within the organization, tasked with tackling what the protocol calls “Actions and Markets Instruments,” released a white paper in December outlining how book-and-claim and related mechanisms might be used. The land-sector document notes at several points that the standard may be amended when the workstream publishes its recommendations.

Yes to removals — but with indefinite monitoring

Many companies want to cut their carbon footprints by investing in on-farm projects that capture carbon dioxide from the atmosphere, such as integrating trees into cropland. The emissions savings can be sizable: Nestlé plans to remove 13 million metric tons of carbon dioxide equivalent emissions from the atmosphere annually to hit its target of halving emissions by 2030.

The good news for companies with such plans is that the new standard provides detailed i