Low-Carbon Agriculture in South America to Mitigate Climate Change and Advance Food Security

João Carlos de Moraes Sá
Seminar

The worldwide historical C losses due to Land Use (LU) and Land Use Change (LUC) are estimated at 145 Pg. South America (SA) is chosen for this study because its soils contain 10.29% (160 Pg C to 1-m depth) of the C stock of the world soils (1550 Pg C to 1-m depth), it is home to 5.67% (0.415 billion people) of world population, and it accounts for 8.64% of the world food production (491 million tons of cereals, vegetables, fruits, roots and tubers, fibers, oil crops and tree nuts) and 20.97 % of the meat (355.3 million tons of cattle and buffalo). The annual C emissions from fossil fuel combustion and cement production in SA represent only 2.39% (0.242 Pg C) of the total world emissions. However, SA contributes 31.27% (0.342 Pg C) of global annual greenhouse gas (GHG) emissions through LU and LUC based on 12.40% (177 million ha) and 8.27% (359 million ha) of the world arable and pasture land area, respectively. Conversely, the potential of SA as a C sink for mitigating climate change with additional Low-Carbon Agriculture (LCA) strategies is 0.62 for 2015 to 2020, 3.36 for 2021 to 2035 and 5.38 Pg C for 2036 to 2050, which can offset 12.1 to 47.8% of the global annual GHG emissions by LU and LUC. Although no-till could contribute 42% (weighted average of 9.396 Pg C for 2015 to 2050 period) towards mitigating GHG emissions, other BMPs can be used synergistically with NT to mitigate climate change. The pay-back time of the SA historical C losses through LCA strategies may be 55 to 120 years. While offsetting anthropogenic emissions, LCA can also increase annual food production in the SA by 132 to 225 million tons [cereals (∼50%), meat (∼40%), and fibers, vegetables and fruits (∼10%)].