Building on a previous study 24 , we used ten climate change and six trade scenarios, and analysed hunger effects at the global and regional levels. Four RCPs (2.6 W m −2 , 4.5 W m −2 , 6.0 W m −2 and 8.5 W m −2

Satisfying China's food demand without harming the environment is one of the greatest sustainability challenges for the coming decades. Here we provide a comprehensive forward-looking assessment of the environmental impacts of China's growing demand on the country itself and on its trading partners. We find that the increasing food demand, especially for livestock products (~16%-30% across all scenarios), would domestically require ~3-12 Mha of additional pasture between 2020 and 2050, resulting in ~−2% to +16% growth in agricultural greenhouse gas (GHG) emissions. The projected ~15%-24% reliance on agricultural imports in 2050 would result in ~90-175 Mha of agricultural land area and ~88-226 MtCO 2 -equivalent yr −1 of GHG emissions virtually imported to China, which account for ~26%-46% and ~13%-32% of China's global environmental impacts, respectively. The distribution of the environmental impacts between China and the rest of the world would substantially depend on development of trade openness. Thus, to limit the negative environmental impacts of its growing food consumption, besides domestic policies, China needs to also take responsibility in the development of sustainable international trade.

Developing and integrating agricultural markets may be key to address Africa's sustainability challenges. By modelling trade costs from farm-gate to potential import markets across eight African regions, we investigate the impact of individual components of continental free trade and the complementary role of domestic agricultural development through increased market access for farmers and agricultural intensification. We find that free trade would increase intra-African agricultural trade six-fold by 2030, butas it does not address local supply constraintsoutside food imports and undernourishment would reduce only marginally. Agricultural development could almost eliminate undernourishment in Africa by 2050, at only a small cost of increased global greenhouse gas emissions. While continental free trade will be enabled in Africa through the African Continental Free Trade Area, aligning this with local agricultural development policies will be crucial to increase intra-African trade gains, promote food security and achieve climate objectives. MainAgriculture plays a key role in ensuring a sustainable future for Africa. Currently, about 19% of the African population is undernourished 1 . Despite rapid growth in agricultural production in Sub-Saharan Africa since 2000 2 , food production did not keep up with increasing food demand thereby building up a high dependency on imports from outside Africa 3 . While international imports increase food availability and diet diversity 4 , they also imply risk from global market uncertainty 5 , especially for countries with high food insecurity and volatile export earnings 6 . Further, production growth in the past decades in Africa relied mainly on cropland expansion rather than yield intensification 2 , driving deforestation and related greenhouse gas (GHG) emissions 7 . Future food demand is expected to continue to grow rapidly in Africa as income increases 8 , the total population doubles 9 and the urban population almost triples 10 by 2050. Meeting this demand without increased import dependence or cropland expansion poses a major challenge 11,12 . In this context, the modernization and regional integration of agri-food systems can be key to eliminate hunger, ensure sustainable production growth and induce broader economic transformation in Africa 2,13-15 . In the past decades the modernization of developing countries' food systems lowered food prices and reduced seasonal variation in food supply 16 . Agricultural productivity growth under the Green Revolution in Asia, Latin America and Middle East tripled global crop production, while being land sparing and emission saving 17 . Improved access to domestic and international markets may in theory also reduce pressures on natural resources by relocating agriculture to the most productive areas, though impacts in the past decades have been negative instead due to deforestation and cropland expansion effects [18][19][20] . In Africa, there is still a huge potential to develop domestic agricultural markets and expand internati...