Forests and woodlands are important stores of planet-warming carbon dioxide, soaking up 30 per cent of emissions from industry and fossil fuels. But every year, the world loses 10 million hectares of forests, an area larger than Portugal. The Green Gigaton Challenge, backed by the United Nations Environment Programme and partners, catalyzes public and private funds to combat deforestation, with the goal to cut annual emissions by 1 gigaton by 2025.