The Earth's Carbon Sinks Are Collapsing
Climate change might be far worse than we thought.
Forests are the planet’s lungs, supplying us with oxygen and burying atmospheric carbon deep in their rich soils. Thousands of studies, articles, and documentaries confidently state that around 30% of humanity’s carbon emissions get absorbed by Earth’s mighty forests. In fact, some even claim these leafy carbon sinks will pull more carbon out of the air as we increase the levels of atmospheric carbon dioxide and, in turn, make trees more efficient. However, while some of this might have once been true, a new paper disputes these claims. As a result, climate change is a much slippier slope than we thought. This paper is a preliminary report first published by the Guardian. It found that in 2023, there was practically zero net carbon absorbed by land. This means that trees still absorbed carbon dioxide, but forests produced an equal amount of carbon dioxide, meaning that overall, no carbon was absorbed by the atmosphere.
Why did this happen? Well, 2023 was the hottest year on record, and as such, almost every significant land ecosystem was hit by unprecedented droughts and wildfires. Both of these events hinder the forest’s ability to bury carbon away and force enormous amounts of stored carbon dioxide to be released back into the atmosphere.
Wildfires do this in the most obvious way: trees can’t photosynthesise if they are burned to the ground, and burning huge swathes of forests will obviously unleash vast quantities of carbon into the air. Droughts also prevent photosynthesis, as every plant needs a water source to photosynthesise properly. However, droughts can also cause carbon trapped in the soil to be released. Wet soils, such as those in swampy forests, can be an anoxic environment, meaning they contain no oxygen, and as such, decomposition can’t occur, so dead biomass stays intact, keeping the carbon it contains locked away. If these soils dry out, like during a drought, bacteria can go wild, the biomass decomposes, and the carbon is released into the atmosphere.
This preliminary report found that the record heat of last year, which human carbon emissions are responsible for, caused enough droughts and wildfires to completely negate the carbon tucked away by the globe’s land ecosystems.
Okay, so what are the implications of that?
Well, this news came as a considerable shock to climate scientists. Their models didn’t consider this negative feedback loop of higher global temperatures causing a collapse of land-based carbon sinks, which will increase the amount of carbon that stays in the atmosphere, which will cause hotter global temperatures, and so on. They presumed that these carbon sinks’ annual capacity would decrease over time but not entirely disappear as suddenly as they have done or potentially reverse and become carbon producers, as this paper suggests they could do in the future. As such, climate change could happen significantly faster than our current predictions suggest.
Considering we are already a country mile away from meeting our climate target of limiting global warming to two degrees Celsius, this is horrific news! It means we could be barreling towards rapid climate change, decimating crucial ecosystems, and causing frequent deadly, infrastructure-ruining, economy-crushing, and refugee crisis-sparking extreme weather far sooner than expected.
So, can we stop this? Or is our fate sealed?
Well, the window to change our climate future is still open, but only just. We need to take massive and decisive action fast.
For example, a study from a few years ago found we could meet our global emissions targets by doing one simple thing: rapidly phasing out coal.
Coal accounts for only 25% of the globe’s energy mix. Yet, it is responsible for around 40% of humanity’s total carbon emissions!
Coal power is mainly used by rapidly developing countries, like India and China, as it was historically by far the cheapest and fastest to expand form of energy we had. However, it is also by far the dirtiest form of energy, producing twice the carbon emissions per kWh of energy as natural gas and up to 200 times more per kWh as renewables. In fact, coal is so dirty that it actually produces more environmental radiation than nuclear power per kWh!
But, over the past five years, renewables have become the new cheapest and fastest energy in town. Some renewable projects can cost half as much as coal plants to run! This cost disparity is so great that it is now actually more profitable to close coal plants early and replace them with renewables than it is to keep the coal plants running to their expected lifespan.
Rapidly replacing a quarter of the world’s energy supply might sound impossible, but it isn’t. A decade ago, coal used to make up 40% of the UK’s energy mix, but the country has now completely phased their usage out. This has made the UK’s carbon emissions drop faster than any other European country despite not building as many renewables as other European countries.
If we could get countries like India and China to adopt an equal or faster coal phase-out, we could reduce our emissions quickly enough to meet our climate goals early and avoid the negative feedback loops highlighted by this preliminary report.
So, yes, climate change could be a far slippier slope than we thought, thanks to land carbon sinks collapsing, but we aren’t powerless to stop this oncoming catastrophe. We have the technology and means to rapidly decarbonise fast enough to save the planet and ourselves. The only question is, will we?
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Sources: Arxive.org , The Guardian, Ecowatch, Down To Earth, Will Lockett, The Brink, Our World In Data, Will Lockett