We are burning too many fossil fuels to fix it by planting trees

Achieving net zero emissions with ‘offset’ systems will be impossible, science warns

The idea that we can mitigate the carbon emissions current ones by ‘offsetting’ them with CO2 reduction initiatives elsewhere It has become a central axis of government and business strategies to combat climate change. But it is an idea that we must seriously question.

Basically, the compensation strategy It assumes that the release into the atmosphere of carbon stored one hundred million years ago by biology can be mitigated in the current biological cycle. Since the Kyoto protocol was signed, offsetting has become the preferred option globally. (…)

Planting trees to mitigate the effects of forest clearing – or to provide shade, stabilize land and improve biodiversity – means that carbon in the atmosphere can be sequestered where it would not otherwise be possible.

But That does not automatically mean that the planet can absorb all the fossil carbon that human industry continues to release.. The idea that the damage caused in the present can be “compensated” somewhere else in the future – something that is also observed in the field of water ecology – cannot be taken literally.

How the carbon cycle works

To put things into perspective, global carbon emissions from burning fossil fuels currently amount to around 10 billion tonnes per year. If we continue emitting at this rate, total fossil fuel emissions between now and 2050 will be approximately 280 billion tons, seven times more than the estimated maximum biological sequestrationwhich is 38 billion tons between 2015 and 2050.

Before humans began extracting fossil fuels, carbon circulated in a dynamic equilibrium: the total amount ‘in’ was balanced by the total amount ‘out’, so the amount of carbon stored did not change.

But then, starting with coal and later oil and gas, this balance was destroyed and carbon stored for millennia is being released.

Despite its ancient origin, this fossil CO2 is ‘new’ carbon added to the current active land-atmosphere-ocean carbon cycle. The reality is that the long-term storage of said material in plants, soils, geological formations and oceans it can only mitigate carbon from the current cycle, but not any additional fossil carbon.

While the tree’s carbon atom is the same as the carbon atom in burning fossil fuels, that’s where the similarity ends. The fossil carbon that the tree supposedly mitigates is a separate and distinct thing.

Planting a tree only mitigates the carbon loss of another tree that no longer exists (the one we cut down, for example). Furthermore, planting trees to mitigate fossil carbon emissions condemns future generations to converting land into forests, which will remain forever.

This entails many risks, including forest fires and storm damage, all caused by drought and rising temperatures. The feedback loop resulting from climate extremes caused by climate change can limit and even stop carbon sequestration in forests.

Planting forests to mitigate this situation means that the land will not be available for possibly better uses, including food production. Still, the world is currently removing trees at twice the rate at which they are replanted.

The carbon trading trap

The now ubiquitous notion of “net zero” emissions It is, at best, a delaying tactic and, at worst, a form of self-deception. because it justifies allowing more fossil carbon to be released endlessly.

In New Zealand, this translates into subtracting from total emissions the carbon sequestered by forests planted since 1990, giving the false impression that they are 27% lower than they really are.

After subtracting sequestered carbon from total emissions, the remainder is called “net emissions,” even though each tree planted replaced a preexisting tree, so fossil emissions were not offset.

Trading fraudulent carbon credits has been a problem in the past, as has the sale of “ghost credits.” In general, it has been shown that “The compensation credits negotiated today in the market do not represent real emissions reductions.”

But the underlying assumption remains that we can mitigate fossil carbon in the current carbon cycle. And this, despite the New Zealand Climate Change Commission making clear that the addition of fossil carbon to the atmosphere is permanent on a human time scale.

More trees alone won’t work

In addition to natural sequestration strategies, artificial carbon capture and storage techniques. However, these technologies require large amounts of energy, are extraordinarily expensive and have limited potential. Most attempts so far they have failed.

Furthermore, as the Intergovernmental Panel on Climate Change (IPCC) has noted, the carbon captured through such technologies will not necessarily be permanent. Crucially, the net energy yield of fossil fuels – that is, the energy they provide versus the energy needed to extract them – is already in sharp decline.

Any carbon capture system will significantly accelerate that decline. According to the IPCC, between 13% and 44% of the energy obtained from the extraction of fossil fuels would be lost in the form of energy necessary for the carbon capture process.

The notion that the planet can reach net zero equilibrium without a widespread economic and social change It only serves to delay the inevitable.

Even if the entire country or planet were replanted with trees, at best they would absorb the equivalent of a decade of current emissions.

It is necessary to reverse deforestation and plant more trees to sequester the carbon emitted by changes made in land use. But Planting trees instead of stopping fossil emissions is not the answer. Planting them and, furthermore, not emitting fossil carbon is the only solution.

Reference article: https://theconversation.com/were-burning-too-much-fossil-fuel-to-fix-by-planting-trees-making-net-zero-emissions-impossible-with-offsets-217437

Mike Joy

He is a senior researcher in Water Ecology at the Morgan Foundation at Victoria University of Wellington (New Zealand).

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