Keep it in the ground – mangrove carbon, that is

Keep it in the ground – mangrove carbon, that is

“Keep it in the ground” has been the motto of climate change campaigners for years. Until now this was in reference to crude oil – but thanks to research recently published in Nature, this could equally mean soil carbon. The research, led by Conservation International scientists, has identified carbon-rich landscapes, including mangrove forests, that contain so much carbon that their conservation is pivotal to avoiding a climate catastrophe – they are calling this ‘irrecoverable carbon’.

Carbon stored by ecosystems is lost to the atmosphere when those ecosystems are destroyed. When the ground is disturbed, as happens when forests are cut down, the soil becomes exposed to the air and the organic carbon is degraded into carbon dioxide. In mangrove forests, deforestation is happening at an alarming rate globally. Mangroves are cut down to make way for shrimp farming, marinas, coastal development and as a source of timber for building and firewood. They are also threatened by pollution, sedimentation and climate change.

Climate scientists have warned that we must reach net-zero emissions by 2050 if we are to limit warming to 1.5 degrees Celsius. Keeping natural carbon sinks – as carbon-rich habitats are known – intact is a vital part to achieving this goal. We must take action to reverse the decline of these habitats to keep that carbon in the ground.

It’s hard to imagine just how much carbon is stored in these habitats. The numbers become unimaginably huge – what does 260 billion tonnes, the amount of this ‘irrecoverable carbon’ – look like? In 2019, global fossil fuel emissions reached nearly 37 billion tonnes CO2, or 10 billion tonnes of carbon. That means that 26 years worth of global emissions, at 2019 emission levels, are locked away in our ecosystems. Losing them would catapult us 26 years closer to climate catastrophe – and it is clear that we don’t have that kind of time on our hands to lose.

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