Accounting for the environmental impact of food waste on water resources and climate change

As human society has developed, food production has developed into a transboundary supply chain that produces wastes during each stage. Decomposed food wastes may release greenhouse gases that contribute to the warming effects of the climate; if incinerated, they could also become sources of SO₂ and NO_x air emissions, which mix with the precipitation and, thus, acidify the soil and water. Degraded and soluble leachate from the food residuals, abundant in nitrogen and phosphorus, may facilitate eutrophication of surface and groundwater. In this chapter, the added impacts on the climate and water resources in relation to food waste are evaluated based on carbon and water footprints. The results showed that the production of livestock, in general, produced a higher carbon footprint than that of plant-based food. On the other hand, the production of cereals, in particular, rice production, contributed to a large amount of total water footprint due to the need of irrigation. Using newly developed treatment technologies, food waste can be a good source for resources and energy recovery that offsets the carbon emission. However, the uncontrolled or contained leachate from food waste treatment can still cost a considerable amount of gray water footprint. In terms of the waste produced during food production, developing countries contributed greater footprints for less-than perfect agricultural practices and waste treatments. They are, however, the major food producers worldwide. On the other hand, developed countries are larger contributors to the footprints during the consumption stages of the food supply chain. Consumers in these countries tend to dispose large quantities of undesirable food after purchasing. To reduce food waste, it may be mutually beneficial for developed countries to export useful technologies in terms of agricultural practices and waste treatments to developing countries. For waste reduction after the food is purchased, education and policy that incentivize consumers to reduce food waste may be the key.