Carbon footprints and land-use systems

Abstract

Carbon Footprint (CFP) refers to the emission of all greenhouse gases (GHGs) during a given period by any activity or entity. The standard unit for measuring it is the carbon dioxide equivalent (CO2eq), such that the impact of each GHG is expressed in terms of the amount of CO2 that would create the same amount of warming. It is widely recognized that the 2020 global value for average per capita CFP (estimated as 4.47 Mg CO2eq) is not sustainable and that it must be reduced to < 2Mg CO2eq if global warming is to be limited to 20C. Recent estimates show that 31% of human-caused GHG emissions originate from the world’s agri-food systems, the major sources being deforestation, livestock production (from enteric fermentation and manure), food waste disposal, and fossil fuel use (by farms and the food-retail sector). Land application of chemicals such as fertilizers, weedicides, and insecticides is the most significant factor in the AFOLU (agriculture, forestry, and other land-use) sector. Enhancement of the natural process of terrestrial C sequestration in soil and vegetation is a widely recognized approach to reducing the AFOLU sector CFP. The adoption of multispecies agroforestry systems with nitrogen-fixing trees is a promising strategy for accomplishing this goal. Another is integrated silvopastoral systems that combine animal production with deep-rooted grass and trees that could counteract the GHG emission through enteric fermentation in animals with enhanced soil C sequestration.