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Food production's climate impact
Global food systems generate roughly a quarter of all human-driven greenhouse gas emissions, stemming from sources like farm machinery, fertilizer production, and livestock digestion. Yet some foods go beyond merely reducing emissions-they actively remove carbon from the atmosphere, offering a potential tool to combat climate change.
What are carbon-negative foods?
Carbon-negative foods absorb more greenhouse gases than they emit during production. Unlike most crops, which release stored carbon when consumed, these foods lock carbon away in long-term storage-such as soil, deep ocean sediments, or durable wood products. While still rare, they could play a role in restoring ecosystems alongside cutting emissions.
Kelp: Ocean-based carbon storage
Fast-growing macroalgae like kelp draw CO₂ from the air as they develop. Fragments that sink to the ocean floor trap carbon in deep-sea sediments. However, the removals per kilogram are modest, so supply chains must minimize energy use in transport, packaging, and processing to achieve net-negative emissions. Local sourcing helps, though most kelp products today fall short of this standard.
Beyond climate benefits, increased kelp consumption could incentivize the restoration of depleted underwater forests, enhancing biodiversity.
Methane-eating bacteria: A novel protein source
Certain bacteria consume methane-a greenhouse gas 30 times more potent than CO₂ over a century-to generate energy. When processed into food products like protein powders or meat substitutes, these bacteria convert methane into far less harmful CO₂. They can also utilize waste streams, such as food scraps or manure, for nutrients.
While no commercial products exist yet, Finnish startup Solar Foods demonstrated the concept in 2023 with a bacteria-based protein used in Singaporean ice cream, hinting at future market potential.
Peatland crops and tree nuts
Rewetted peatlands accumulate carbon faster than it decomposes, making crops like blueberries, cranberries, and celery grown in these environments candidates for carbon negativity-if supply chains remain low-emission. Most fresh blueberries, however, are shipped globally in plastic packaging, offsetting their benefits.
Tree nuts, meanwhile, store carbon as they grow. Global nut cultivation has doubled in 20 years, often on former cropland. A typical nut product removes about 1.3 kg of CO₂ per kilogram, with storage lasting until trees mature (roughly 20 years). Long-lived wood products can extend this storage further.
Regenerative farming: Progress and limits
Practices like reduced tillage and hedgerow planting boost soil carbon storage. UK-based Wildfarmed reports its regenerative wheat removes 1.5 kg of CO₂ per kilogram produced. London's Gipsy Hill Brewery claims its beer is carbon-negative, backed by lifecycle assessments.
Yet high-emission foods like beef are unlikely to achieve carbon negativity through these methods alone. An Argentinian farm certified its beef as removing 0.3 kg of CO₂ per kilogram-but required 500 square meters of land per kilogram of meat. Scaling this globally would demand an additional 3 billion hectares of farmland, an area larger than Africa.
Land sparing: The most effective strategy
Carbon-negative foods alone may never dominate diets due to limited scalability. A more powerful approach involves reducing land use. For example, beef requires 100 square meters per 100 grams of protein, while plant-based alternatives like beans or tofu need just 5 square meters.
A climate model found that shifting entirely to plant-based diets could free 3.1 billion hectares-an area the size of the U.S., China, the EU, and Australia combined-for rewilding. This would remove 8 billion tons of CO₂ annually for a century, offsetting all food-related emissions and turning global diets carbon-negative.
On average, such a shift would reduce per-person food emissions from 2,000 kg CO₂ equivalent yearly to -160 kg CO₂ equivalent.
Challenges and future solutions
Identifying carbon-negative foods today is difficult, but emerging carbon labeling systems could help. New Zealand now requires farms to quantify emissions, while France plans a national carbon-labeling rollout. Once standardized and regulated, these schemes may make it easier for consumers to choose climate-friendly options.
While carbon-negative foods offer promise, broader dietary changes-particularly reducing land-intensive animal products-remain the most effective way to achieve net-negative food systems.
"Swapping high-land-use products like meat and dairy for low-land-use alternatives is likely the most impactful way to make diets carbon-negative," says Joseph Poore, director of the Oxford Martin Programme on Food Sustainability.
