Massive tree planting schemes are not the answer to the biodiversity and climate crises

In October 2021, the first phase of the postponed Conference of the Parties to the Convention on Biological Diversity (COP15) took place online. Included among the proposals for COP15 are plans to protect 30% of the planet by 2030 (30×30).

The High Ambition Coalition for Nature and People, an intergovernmental group led by France and Costa Rica with 78 member governments, is pushing for the 30×30 target to be approved at COP15.

The High Ambition Coalition argues that,

In order to address both the biodiversity crisis and the climate crisis, there is growing scientific research that half of the planet must be kept in a natural state.

This is based on the late-E. O. Wilson’s 2016 book, Half-Earth: Our Planet’s Fight for Life. But this proposal is extremely controversial and could affect more than one billion people living in and around the proposed protected areas.

Massive tree planting schemes

IUCN defines “nature-based solutions” as “actions to protect, sustainably manage, and restore natural and modified ecosystems”. IUCN hopes that such initiatives will provide “human well-being and biodiversity benefits”, there is a serious danger that “nature-based solutions” will distract from real climate solutions, and have serious impacts on both biodiversity and local communities.

During the first phase of COP15, Ian Scoones, Professorial Fellow at the Institute of Development Studies at the University of Sussex in the UK, wrote an article questioning the role of tree-planting and “nature-based solutions” in addressing the biodiversity and climate crises.

Scoones notes that there are several massive tree-planting schemes already underway:

• The UN Bonn Challenge, covering 350 million hectares – 45% of which is planned to become monoculture tree plantations;

• The Sahel’s Great Green Wall – in January 2021, France, the World Bank and others promised US$14 billion to the Great Green Wall initiative at the One Planet Summit. A report by the World Bank’s Independent Evaluation Group found that “the use of area enclosures – a land management practice that seeks to restore degraded land by excluding livestock and humans from openly accessing it in the short to medium term – [which] runs the risk of exacerbating vulnerability” of those reliant on communal lands. The Bretton Woods Project described the Great Green Wall as “a desert mirage”.

• The African Forest Landscape Restoration Initiative aims to restore 100 million hectares of land in Africa by 2030. A 2019 paper argues that, “[T]he afforestation envisaged by the global tree planting programmes is based on wrong assumptions. Far from being deforested and degraded, Africa’s savannas and grasslands existed, alongside forests, for millions of years before humans began felling forests.” And a 2021 Global Forest Coalition found that AFR100’s targets include a vast area of industrial tree plantations.

• The World Economic Forum’s Trillion Trees Initiative aims to plant one trillion trees by 2030. A 2020 paper in BioScience highlights ten pitfalls with the initiative. The pitfalls include (among others) the following: Ecosystems, not tree planting campaigns, capture and store carbon; Tree plantations sequester less carbon than naturally regenerated forests; Trees can reduce water availability; Tree planting threatens rural livelihoods; and Tree planting targets the global south to capture emissions from the global north.

“Bad Science”

Scoones notes that the World Resources Institute and the Crowther Lab at ETH Zürich identify millions of hectares of grasslands for forest ‘restoration’. The assumption is that these grasslands are “‘degraded’ forests in need of rehabilitation, rather than highly productive, biodiverse ecosystems that support many livestock and people,” Scoones writes.

William Bond, a grasslands researcher an d emeritus professor atthe University of Cape Town, told Mongabay that maps such as WRI’s Atlas of Forest Landscape Restoration Opportunities, published together with IUCN, “have been extremely damaging”. Bond added that,

“It was really superficial, bad science, but then international policies are feeding into this. The vast areas then became the targets for reforestation, supported by the World Bank, the IUCN, the German government and so on.”

Scoones argues that from a climate perspective, planting trees on grasslands makes little sense. Carbon forestry schemes “focus on the above-ground biomass, and tree biomass is much more visible and measurable that the poorly-understood underground carbon dynamics among root networks and in the soil”. Scoones writes that,

Grasslands may also fix carbon more effectively than forests, although estimates vary wildly. In the geological past, the expansion of grasslands may have locked up so much carbon it resulted in a cooling of the atmosphere, precipitating an ice age. Grasslands have extensive root systems and high turnover, with dead vegetation matter regularly incorporated into the soil, often assisted by grazers. Grasslands can be more reflective of solar radiation too compared to darker forests, and so may act to cool the earth.

Putting people first

Scoones highlights seven problems with tree planting, based in part on the 2020 paper in BioScience mentioned above. One of the problems is that, “Carbon projects require managed tree planting to claim carbon credits against an assumed degraded baseline.” Industrial tree plantations are easy to manage, and consulting firms can quickly calculate the number of carbon credits generated. But industrial tree plantations exclude people, livestock, and wildlife. Monoculture tree plantations are the opposite of biodiverse.

A recent Oxfam report highlights the dangers of “net zero” climate targets:

[T]hese targets risk being reliant on using vast swathes of land in low-income countries to capture carbon emissions, allowing the biggest emitters to avoid making significant cuts in their own emissions. ‘Net zero’ could end up being a dangerous distraction that could delay the rapid reductions in emissions that high-emitting countries and companies need to make if we are to avoid catastrophic climate breakdown. It could also lead to an explosion in demand for land which, if not subject to careful safeguards, might risk increasing hunger and fuelling land inequality.

Scoones points out that trees are part of grassland landscapes and have benefits for people and environments, providing shade, fruits, food for grazing animals, leaf litter, and so on. Scoones suggests that it often makes more sense to encourage regrowth of existing trees and that the people living in these grassland ecosystems are crucial to their management. Scoones writes that,

Pastoralists know a lot about highly dynamic rangeland environments. As guardians of these rich, open ecosystems, excluding pastoralists and their animals in the name of carbon offsetting and forest rehabilitation can be disastrous, both for people and for the environment.

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