Why planting trees is not a silver bullet against climate change

“Nature-based solutions” are gaining ground as a means to combat climate change and protect biodiversity. Tree planting, a key part of several countries’ COP26 pledges, is one such proposal, but experts say reforestation, while essential, is far from a silver bullet to climate crises.

Two of the world’s largest fossil fuel producers, Russia and Saudi Arabia, have vowed in recent weeks to become carbon neutral by 2060. Both Moscow and Riyadh plan to offset much of their carbon emissions from fossil fuels by planting millions of trees.

And they are not alone. COP26 host Boris Johnson wants tree planting to be a priority at the UN climate conference alongside additional actions on “coal, cars and cash.”

“To have zero net carbon emissions, it must be net positive for trees, and by 2030 we want to plant many more trees around the world than we are losing,” the British prime minister said in August.

Tree planting belongs to a broader set of environmental measures known as “nature-based solutions”, which according to the UN and many scientists are critical to preventing catastrophic climate change, and which COP26 organizers hope to boost the mainstream.

The International Union for Conservation of Nature (IUCN), which coined the term, defines nature-based solutions as “actions to protect, sustainably manage and restore natural and modified ecosystems.” The protection and expansion of forests is central to this approach.

“Forests, and in particular tropical forests, absorb around a third of the greenhouse gases emitted each year,” explained Anne Larigauderie, executive secretary of the Intergovernmental Science and Policy Platform on Biodiversity and Ecosystem Services (IPBES ), who works with the UN to protect biodiversity, in an interview with FRANCE 24. “They could do much more if we stopped deforestation and invested more in forest management and the protection of these ecosystems.”

Mangrove restoration is often cited as a key example, as these unique ecosystems act as natural barriers against coastal erosion and flooding.

However, simply planting trees doesn’t cut it.

“Nature-based solutions should have a double benefit,” said Freddy Rey, an ecological engineering specialist at the French National Institute for Agronomic Research (INRAE). “At least one should be of concern to nature and the other to society, for example, the fight against climate change, health, food safety or protection against natural hazards.”

In France, INRAE ​​researchers have added vegetation along the banks of some waterways to combat erosion and thus flooding. Rey said this offers a more durable alternative to traditional dams.

“Over time, vegetation will spread, while artificial barriers will wear out,” he told FRANCE 24. According to IUCN, nature-based solutions tend to be less expensive in the long term than building and maintaining technological infrastructure. .

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‘Buzz’ around nature-based solutions

Of course, planting trees and expanding green spaces are not new ideas. But Rey said that, in France at least, the label of “nature-based solutions” has managed to “create a stir” around green practices, especially among elected officials. Legislators are working with INRAE ​​to develop solutions to local environmental problems. NGOs such as the France Nature Environment group are also involved, which last year published a guide for cities seeking to implement this type of solution.

While practices such as reforestation may be “low-tech,” they still require highly specialized research and innovation.

“Far from being simply ornamental greening projects, the maintenance of which often involves intensive use of water, energy and fertilizers, nature-based solutions are based on scientific knowledge and technical knowledge drawn largely from ecological engineering.” said a recent study.

Larigauderie from IPBES laments that, in major international climate talks, “people often talk about technical and technological solutions … and do not pay enough attention to nature as a source of solutions.”

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Despite all the promise they hold, nature-based solutions should not be viewed as a miracle cure for the climate. The natural world is constantly changing and evolving, and researchers must adapt accordingly. Planting along coasts and streams, for example, has its limits.

“Although we have mastered the design methods for civil engineering based on mechanical and physical properties, the same is not the case with plant engineering, which brings into play living materials whose properties are much more difficult to control,” said the INRAE ​​researcher André Evette in a statement.

Mountainous regions, lakes and actively used waterways present particular challenges.

Disguise ‘climate destruction’

“We shouldn’t think that we are going to change the world with plant stems. We are not going to stop the tidal waves with branches, ”Rey said. “You need a balance between these nature-based solutions and civil engineering knowledge.”

Meanwhile, some NGOs, such as Friends of the Earth, fear that nature-based solutions could “disguise business that destroys the climate as usual.”

“Under the guise of Nature-Based Solutions, big business and governments continue to expand … industrial agriculture and fossil fuel extraction, while claiming to address their climate impacts through investment in activities such as the massive planting of trees, “wrote Friends of the Earth in a recent statement.

Larigauderie also noted that the concept can be slippery and cautions against putting too much at stake.

“Nature will not be able to absorb a frenzied increase in our consumption,” he warned. “The number one message is that we must reduce our energy consumption and rethink our lifestyles and agriculture. Nature can do a lot for us, but we must also correct ourselves. ”

The COP26 summit will take stock of the actions taken by governments to meet the targets set by the 2015 Paris Agreement and the tough challenges that remain to keep global warming below 1.5 ° or even 2 ° Celsius. Building on recent COP15 talks on biodiversity, COP26 has nature-based solutions on the agenda, with one of its 10 days of work dedicated to the nature issue.

Many hope it is just the beginning of what the UN calls “an essential part of the overall global effort to achieve the goals of the Paris Agreement.”