Trees and land absorbed almost no carbon dioxide (CO2) last year, and scientists are struggling to work out why.
Carbon sinks, such as forests, oceans and soils, are an essential part of regulating the Earth’s climate. Through natural processes, these land and ocean masses absorb almost half of all human carbon emissions from the atmosphere.
But preliminary findings for 2023 – the hottest year ever recorded on Earth – have found that the amount of carbon absorbed by land has temporarily collapsed.
Researchers discovered forests, plants and soil, as a net category, absorbed almost no CO2 last year.
This was completely unexpected, and therefore not something factored into most predictions and calculations about how quickly the Earth will heat up as a result of climate change.
Rising temperatures, extreme weather and droughts are destabilising ecosystems, pushing them into uncharted territory, the Guardian reports.
The breakdown of the land carbon sink could be temporary, but if it isn’t, this will drastically increase the rate of global heating.
Global carbon emissions continue to increase. In 2023, global energy-relate CO2 emissions reached a record 37.4bn tonnes.
It will be impossible for the world to reach net zero without carbon sinks, because there is simply no human technology that can absorb carbon on the same scale as the forests, grasslands, peat bogs and oceans of the world.
It’s not just land carbon sinks that are showing worrying signs either. As Greenland’s glaciers and Arctic ice sheets continue to melt at ever quickening rates, the Gulf Stream is being disrupted. This in turn is slowing the rate at which the ocean absorbs carbon.
Meanwhile, melting sea ice is exposing zooplankton to more sunlight. These organisms rise to the surface of the ocean at night to feed on microscopic algae, with the waste from this then sinking to the ocean floor, removing millions of tonnes of carbon from the atmosphere each year.
If exposed to more daylight, scientists fear the zooplankton could end up staying in the depths longer, disrupting their feeding that stores carbon on the ocean floor.
Speaking at New York Climate Week in September, Johan Rockström, director of the Potsdam Institute for Climate Impact Research, said: “We’re seeing cracks in the resilience of the Earth’s systems. We’re seeing massive cracks on land – terrestrial ecosystems are losing their carbon store and carbon uptake capacity, but the oceans are also showing signs of instability.
“Nature has so far balanced our abuse. This is coming to an end.”
“This stressed planet has been silently helping us and allowing us to shove our debt under the carpet thanks to biodiversity,” he said. “We are lulled into a comfort zone – we cannot really see the crisis.”
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