Logging devastation in Mapuche Territory, Chile. Photo: Langelle
Restoring Natural Forests is the Best Way to Remove Atmospheric Carbon
Nature April 2, 2019
Simon L. Lewis, Charlotte E. Wheeler, Edward T.A. Mitchard & Alexander Koch
Keeping global warming below 1.5 °C to avoid dangerous climate change1requires the removal of vast amounts of carbon dioxide from the atmosphere, as well as drastic cuts in emissions. The Intergovernmental Panel on Climate Change (IPCC) suggests that around 730 billion tonnes of CO2 (730 petagrams of CO2, or 199 petagrams of carbon, Pg C) must be taken out of the atmosphere by the end of this century2. That is equivalent to all the CO2emitted by the United States, the United Kingdom, Germany and China since the Industrial Revolution. No one knows how to capture so much CO2.
Forests must play a part. Locking up carbon in ecosystems is proven, safe and often affordable3. Increasing tree cover has other benefits, from protecting biodiversity to managing water and creating jobs.
The IPCC suggests that boosting the total area of the world’s forests, woodlands and woody savannahs could store around one-quarter of the atmospheric carbon necessary to limit global warming to 1.5 °C above pre-industrial levels2. In the near term, this means adding up to 24 million hectares (Mha) of forest every year from now until 2030.
Policymakers are sowing the seeds. For example, in 2011, the German government and the International Union for Conservation of Nature launched the Bonn Challenge, which aims to restore 350 Mha of forest by 2030. Under this initiative and others, 43 countries across the tropics and subtropics where trees grow quickly, including Brazil, India and China, have committed nearly 300 Mha of degraded land (see Supplementary Information, Table S1). That’s encouraging.
But will this policy work? Here we show that, under current plans, it will not. A closer look at countries’ reports reveals that almost half of the pledged area is set to become plantations of commercial trees (see Table S1). Although these can support local economies, plantations are much poorer at storing carbon than are natural forests, which develop with little or no disturbance from humans. The regular harvesting and clearing of plantations releases stored CO2 back into the atmosphere every 10–20 years. By contrast, natural forests continue to sequester carbon for many decades4.
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