Reducing carbon footprints of agriculture and food systems

Increase in global populations of humans and domesticated livestock are impacting the resource use and have a large ecological footprint (EFP). The ever-increasing EFP of humanity is accelerating climate change, increasing water scarcity and contamination, aggravating soil degradation, and dwindling above and below-ground biodiversity. Several sub-components of EFP include resource footprint (RFP) which comprises land (LFP), water (WFP), nitrogen (NFP), biodiversity (BFP) power (PFP), carbon (CFP), etc. Agricultural practices (e.g., tillage, fertilizer and pesticide use, farm operations such as irrigation, harvesting, baling, etc.) also cause the emission of greenhouse gases (GHGs) such as CO2, CH4, and N2O, and these gasses differ in their global warming potential (GWP). In general, CFP is reported as CO2eq by converting CH4 and N2O into CO2. The Human diet, consisting of plant and/or animal-based products and grown diversely with or without chemicals, irrigation, and modern innovations, has a wide range of EFP. The latter, is the widely used measure of resource consumption and humanity’s impact on the planet. EFP encompasses the cumulative GHG emissions by an individual, community, organization, institution, nation for a specific service or product. It can vary widely because of using different reference systems of the studies and differences in system boundaries. Therefore, standardization of the methodologies may require a better understanding of the various ways related CFP concepts are relevant for decisions at individual to global levels. There is no one size that fits all. It is also widely recognized that the global average per capita CFP of humanity, estimated at 4.47 Mg CO2eq in 2020 is not sustainable, and must be reduced to < 2 Mg CO2eqif the global warming is to be limited to 2 0C. Therefore, understanding the magnitude of CFP of agriculture and food systems (FSs), and factors affecting it, can lead to identification of technological options which can enhance the use efficiency of inputs, reduce wastage, and decrease the CFP. Different FSs affect CFP through diverse components of production and supply chains, and in the manner in which food is stored and cooked and the waste is disposed or recycled. There is need to adopt international standard (ISO) protocol. Therefore, this review identifies and deliberates technological options which may be needed for reducing CFP of humanity in general but that of agriculture and FSs in particular, while also advancing Sustainable Development Goals of the Agenda 2030 of the United Nations. CFP of diverse agro-ecosystems, land use and management systems are also discussed. Specific examples of CFP include type of farming systems (organic vs.. conventional, dietary preferences, and food waste). There are several options for the humanity to change lifestyle and make it more sustainable. Food waste, about one-third of all, is an important factor impacting CFP while also accelerating global warming. The impact of avoidable food waste on gaseous emissions, estimated at 2.0 to 3.6 Mg CO2eq per Mg of food waste on dry weight basis, must be minimized.