From nuts to kelp: The 'carbon-negative' foods that help reverse climate change

Eating low-carbon foods helps reduce emissions, but some foods actually suck up carbon from the atmosphere, leaving the climate in a better place.

However, there are some foods that remove more greenhouse gases than they emit, often referred to as "carbon negative" foods. These foods leave the climate better than they found it. Producing and eating more of these could help reduce the carbon impact of our food and, in some cases, restore ecosystems in the process.

When plants grow, they take carbon dioxide (CO2) from the air, but when we (or animals) metabolise these plants, this CO2 usually gets released straight back into the air.

These removals last until the trees reach maturity, usually at around 20 years. If the trees are used to make long-lasting wood products at the end of their life, this carbon can remain stored for much longer.

For all the potential of carbon negative foods, they may always only make up a small part of our diets; there just aren't enough products with carbon negative potential, and regenerative practices probably can't offset high emissions foods. So, we need other strategies for carbon negativity too.

While carbon labelling and new technologies are vital for our shift to carbon negativity, swapping from products that use lots of land (generally meat and dairy) to products that use little land (generally plant-based foods) is probably the most effective way to make our diets carbon negative.

* Joseph Poore is director of the Oxford Martin Programme on Food Sustainability. He researches the environmental impacts of global agriculture and how to reduce these impacts.