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 CO2 emitted 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.