How Much Carbon Can Trees Take In?

With climate change one of the major challenges of the modern era, more and more focus is being placed on how countries, governments and individuals across the world can reduce their carbon footprint. While altering our daily lifestyles to emit less amounts of greenhouse gases (GHGs) into the environment is key to preventing the worst effects of climate change, addressing the carbon that is already present in the atmosphere is another important area of research.

Much has been made about the potential of carbon capture and storage (CCs) in this respect, although there are still many obstacles to be overcome before CCS is viable on a mass scale. One natural solution that already provides a great carbon sink is the Earth’s forested areas, which have come under unprecedented threat in recent decades.

With more and more of the planet’s land surface being given over to agriculture, industry and urbanisation, deforestation is occurring on a never-before-seen scale. However, one study from China illustrates the value that the humble tree holds when it comes to removing carbon from our environment.

The Chinese example

China is notorious for being the biggest emitter of human-produced carbon dioxide (CO2), responsible for over a quarter (28%) of global emissions. However, it has been making strikes to shake that ignominious reputation in recent years, and one key part of its strategy has been to plant billions of trees across the nation in order to act as natural carbon sinks.

As well as absorbing CO2 from the environment, these new forests can also alleviate the ill-effects of soil erosion and desertification, as well as providing an economic boon in the form of a lucrative timber and paper industry.

Until now, the effects of those reforesting efforts had not been fully quantified, but a study conducted by the Chinese Academy of Sciences aimed to right that wrong. Using a mixture of the most modern ground-based monitoring solutions and corroborating satellite data, the team behind the research were able to create a reliable picture of how well those sinks are working.

In particular, forested areas in the southwestern provinces of Guangxi, Guizhou and Yunnan showed remarkable promise, capable of absorbing up to 0.35 petagrams per year, while another area in the northeastern provinces of Heilongjiang and Jilin had the capacity to remove a further 0.05 petagrams per annum.

“Not a free pass”

For context, the total amount of carbon being released into the atmosphere from fossil fuel-based activities across China in 2017 was 2.67, signalling that these new sinks are removing a significant chunk from the environment. Therefore, the study makes for highly encouraging reading, but observers have warned that there is still much work ahead.

“With China setting out its ambition for net zero, it's obviously crucial to know the size of the national carbon sink, so this is an important study,” explained Richard Black, director of the environmental thinktank Energy and Climate Intelligence Unit (ECIU).  

“However, although the forest sink is bigger than thought, no-one should mistake this as constituting a 'free pass' way to reach net zero. For one thing, carbon absorption will be needed to compensate for ongoing emissions of all greenhouse gases, not just CO2; for another, the carbon balance of China's forests may be compromised by climate change impacts, as we're seeing now in places such as California, Australia and Russia.”