In recent years, the idea of using afforestation to absorb carbon dioxide and combat climate change has been widely publicized. However, the actual effect and impact during the operation are far from expected.
How trees absorb carbon
Carbon dioxide in the atmosphere is absorbed by trees through photosynthesis, and then converted into organic matter needed for tree growth, and the carbon is fixed in the wood and root systems. This process literally removes carbon from the atmosphere and is a key link in the natural cycle that cannot be ignored.
There are great differences in the carbon sequestration ability of different types of trees. Fast-growing tree species sequester carbon relatively quickly in the early stages, but the rate decreases as they mature. In addition, carbon sequestration by trees is a relatively slow process that lasts for decades, and there is no way to offset the large amount of greenhouse gases continuously emitted by human activities in a short period of time.
The practical dilemma of large-scale afforestation
From 1974 to 2012, millions of hectares of new forests were planted globally with the goal of increasing carbon sequestration. However, subsequent independent analysis concluded that these investments failed to result in a significant reduction in atmospheric carbon concentrations.
Large-scale tree planting projects often face problems such as low survival rates. For example, in 2019, a report was released stating that in an afforestation project in India, most of the land planned to be used was already covered with forests, and the so-called "new tree planting" only replaced the original vegetation and did not produce additional carbon absorption.
Monoculture and ecological risks
In order to pursue efficiency, many afforestation projects will select single tree species and plant them in an intensive manner to form artificial forests. Although this situation is convenient in management, it will cause damage to the biodiversity and stability of the original ecosystem.
This type of artificial forest ecosystem is fragile and susceptible to attacks by pests and diseases, and may also affect the local climate by changing the surface albedo. Planting trees in non-native forest areas may even cause warming, such as in high latitudes or high altitudes.
Land and food security conflicts
Carbon neutrality plans, such as those developed by some companies and governments, require extremely large afforestation areas. In 2021, a report prepared and published by Oxfam calculated that four large oil and gas companies will need to occupy an area equivalent to two British areas in order to achieve tree planting goals.
This has created fierce competition for agricultural land, which could pose a threat to global food security. Using land suitable for farming to plant trees and relocating local communities from the land will cause serious social equity problems.
Misleading Carbon Offset Markets
Sometimes, afforestation is packaged as a so-called "carbon offset" product. In this case, it allows emitters to claim that they have achieved "carbon neutrality" by investing in tree planting. In this way, it is easy for the public and enterprises to misunderstand and think that the high-emission model can be continued.
In reality, the carbon sequestration effects of many such projects are difficult to accurately measure and maintain over the long term. Forests are prone to releasing stored carbon due to fire, logging, or pests and diseases, making so-called "carbon credits" extremely unreliable.
More fundamental climate solutions
Fundamental to addressing climate change is the rapid and ongoing reduction or elimination of fossil fuel use and the shift towards renewable energy sources. Placing too much hope on the carbon sinks contained in future forests will delay ongoing efforts to reduce emissions.
We need to protect the existing natural carbon pools such as virgin forests, wetlands and peatlands. Their carbon sequestration and ecological value are much higher than those of newly created plantations. Real climate action should be based on scientific, fair and systematic emission reduction.
As far as the propaganda of relying on tree planting to achieve "net-zero emissions" is concerned, how do you think we can build a more effective supervision system to ensure that it is actually beneficial to the environment, rather than becoming a tool of greenwashing? You are welcome to share your views in the comment area, and please like this article to support it and encourage more people to participate in the discussion.
