Hidden carbon: Fungi and their 'necromass' absorb one-third of the carbon emitted by burning fossil fuels every year

• These mycorrhizal fungi live in partnership with plants, offering nutrients, water and protection from pests in exchange for carbon-rich sugars.
• Now, new research shows this single group of fungi may quietly be playing a bigger role in storing carbon than we thought.
• These microscopic filaments take up the equivalent of more than a third (36%) of the world’s annual carbon emissions from fossil fuels – every year.

This fungi-plant partnership is 400 million years old

• They thread networks of microscopic filaments through the soil and into the roots of almost every plant on earth.
• They’ve been partnering with plants for more than 400 million years.
• In return, plants pump sugars and fat made by photosynthesis in their leaves down through their roots to the fungi.

How do these fungi fit into the carbon cycle?

• Now we know the carbon transfer from plants to mycorrhizal fungi isn’t a side note – it’s a substantial part of this equation.
• By analysing almost 200 datasets, the researchers estimate the world’s plants are transferring a staggering 3.58 billion tonnes of carbon per year to this underground network.
• Here's what the evidence says

  To be clear, fungal carbon doesn’t present a climate solution by itself.

What does this mean for the climate?

• Once in the soil, these compounds can be used by other soil microorganisms, such as bacteria.
• In fact, other studies suggest this fungal necromass might contribute more to the carbon content of soil than living fungi.
• What does this mean for climate change?
• While atmospheric CO₂ concentrations keep rising, it doesn’t necessarily mean fungi are storing more of it.

Protecting our fungal networks

• When we cut down forests or clear land, we not only disrupt life above the ground, but underground as well.
• We need to safeguard these hidden fungal networks which give our plants resilience – and play a key role in the carbon cycle.
• But as we learn more about how fungi and plants cooperate and store carbon, it’s well past time for that to change.