Dobson, Andy; Hopcraft Grant; Simon Mduma; Joseph O. Gutu; John Fryxell; T. Michael Anderson; Sally Archibald; Caroline Lemann; Joyce Poole; Tim Caro; Monique Borgerhoff Mulder; Robert D. Holt; Joel Berger; Daniel I. Rubenstein; Paula Kahumbu; Emmanuel N. Chidumayo; E. J. Milner-Gulland; Dolph Schluter; Sarah Otto; Andrew Balmford; David Wilcove; Stuart Pimm; Joseph W. Veldman; Han Olff; Reed Noss; Ricard Holdo; Colin Beale; Gareth Hempson; Yustina Kiwango; David Lindenmayer; William Bond; Mark Ritchie and Anthony R. E. Sinclair
On the second day of the 2021 United Nations Climate Change Conference (COP26), 130 nations announced a decision to halt global deforestation by 2030 (1). This is a welcome move and a political success, but ecologically it falls short. The plan needs to be expanded to include savannas, which cover an area of 20 million km2—more than the 17 million km2 covered by tropical forests (2)—and are potentially more important carbon sinks than forests. In the course of a year, each hectare of the Serengeti plains in Tanzania removes between 500 and 2000 kg of carbon dioxide (3) from the atmosphere, enough in total to offset every airline flight to East Africa and all the emissions produced in the region (4, 5). The repeated grazing of wildebeests, zebras, and a variety of insects (6) stimulates vegetative growth multiple times within a year (7, 8), which considerably increases the volume of carbon dioxide absorbed from the atmosphere. Wildlife feces and carcasses enrich the store of carbon and nitrogen in the soil. The Serengeti and other tropical and temperate savannas, which store carbon in the soil rather than in the biomass of trees (4), can capture at least as much carbon as tropical forests if managed correctly (9, 10). They are as threatened as tropical forests by agriculture expansion and land clearing. Like tropical forests, they are crucially in need of protection (11, 12); excessive grazing and fires are diminishing the abundance of wild herbivores and thus their potential to store carbon (8, 10). Substantial amounts of biodiversity, as well as many pastoralist peoples, depend on savannahs. They also generate employment and foreign currency through tourism (5).