The oil company Shell recently miscalculated the extent of its reserves on a pretty massive scale. The mistake meant its new scenario for meeting the internationally agreed 1.5°C climate target would need a new forest about the size of Brazil. And that renewed a debate about just what trees can do to ease the climate crisis.
Tree planting to tackle possibly irreversible climate change is one hopeful route. Trees not only breathe carbon dioxide in; they also breathe out oxygen. But tree planting is more complex than it may seem, Climate News Network reports.
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In its 2018 Special Report, the Intergovernmental Panel on Climate Change (IPCC) says that if the world wants to limit temperature rise to 1.5°C by 2050, an extra one billion hectares (2.4 billion acres) of trees will be needed. But what types of trees, and where? Many different initiatives across the world have tried to restore woodland, but what works best for people and the biosphere?
The UK-based Rapid Transition Alliance (RTA) argues that humankind must undertake “widespread behaviour change to sustainable lifestyles…to live within planetary ecological boundaries and to limit global warming to below 1.5°C” (the more stringent limit set by the Paris Agreement). It has several suggestions for understanding how trees might best help to cool the climate crisis, not least relying on natural forest regeneration rather than commercial plantations.
Over the last decade, several reforestation and afforestation schemes have sprung up under the program of the UN Convention to Combat Desertification (UNCCD).
National and regional reforestation initiatives include China’s forest rehabilitation program and Africa’s Great Green Wall scheme linking North Africa, the Sahel (the area south of the Sahara desert), and the Horn of Africa.
In 2019 the UN Food and Agriculture Organization (FAO) launched a similar reforestation plan targeting cities—the Great Green Wall for Cities initiative. This is expected to remove from 0.5 to 5.0 gigatonnes of CO2 from the atmosphere every year.
In 2017, Pakistan met its target of planting a billion trees and made a commitment to reach 10 billion trees within five years. In neighbouring India, 66 million trees were planted in a record-breaking, 12-hour campaign involving 1.5 million volunteers. Some other countries have relied on equally novel methods; Myanmar used drones to plant trees.
Ambitious projects like these can sound attractive. But their ability to achieve their goals sometimes proves controversial.
Several climate and forest scientists favour what they call “natural forest regeneration”—essentially letting the forest grow back naturally—which often proves to be the most efficient and cheapest approach in achieving natural carbon sequestration.
And yet, only 34% of the total area dedicated to forest restoration plans covered by the Bonn Challenge is earmarked for this approach.
A further 21% of land is reserved for agroforestry, a method promoting the production of multiple plants and crops side by side. The remaining 45% of the land area is given up to the monoculture production of trees.
Better ways of doing things are exemplified by Ghana and Malaysia, for example, where people restored their local forests after being granted ownership of the land.
In Ghana, the forest restoration projects found to be most successful were those which included a “rights-based approach”. Strengthening community rights contributed to the protection of forests from appropriation and privatization and ensured greater accountability and the right to speak out, while providing safeguards against illegal practices.
In Malaysia, an NGO supported Penan Indigenous communities in fighting for their legitimate entitlement to land rights in court. The Penan have strong ties with the land and forests, which play a strong role in maintaining local biodiversity.
Tree planting programs have had very mixed results. Many failures occurred because the trees planted were not suitable for local climate conditions, and others depleted groundwater reserves, leaving nearby soils dried out and damaging local agricultural production.
Natural forest restoration is the most effective way to store carbon from the atmosphere, the RTA argues. These forests are 40 times more effective than plantations and six times better than agroforestry at retaining carbon. Their complex ecological systems are also better for biodiversity.
The RTA says there are four main ways for countries to encourage the successful restoration of natural forests so as to temper the effects of the climate crisis:
• They should increase the proportion of their land allocated for regeneration to natural forest;
• Priority should be given to humid tropical areas, such as Amazonia, Borneo, and the Congo Basin, which support high biomass forest, using international climate adaptation and conservation funds to support such action;
• Countries should focus on naturally regenerating existing carbon stocks such as degraded forests and partly wooded areas, using treeless regions for plantations or agroforestry;
• Restored forest must be protected, perhaps by giving title rights to Indigenous peoples who protect forested land, changing the legal definition of land use so that it cannot be converted to agriculture, and ensuring that commodities companies cannot clear restored forests.
Restoring natural forests, the Alliance concludes, is the most efficient, fast, safe, and under-valued carbon sequestration tool. – Climate News Network