Can carbon footprint serve as an indicator of the environmental impact of meat production?

摘要

The carbon footprint (CF), the amount of greenhouse gases (GHG) emitted during a product's lifecycle, was evaluated as an indicator of the wider environmental impacts of meat production using existing life cycle assessments of different types of meat (pork, chicken and beef). The CF generally acts as an indicator of acidification and eutrophication potential, since more efficient use of nitrogen leads to less eutrophying and acidifying substances being released to the environment and to lower GHG emissions in nitrous oxide form. GHG mitigation strategies based on more efficient use of feed can therefore also lead to decreased acidification and eutrophication potential. Decreased GHG emissions due to increased productivity mean less land is required for feed production, so CF can act as a proxy for land use. For the impact category primary energy use, apparent conflicts with CF were identified. Pasture-based beef production can be either very energy-efficient or energy-demanding, but both forms produce high CH_4 emissions from enteric fermentation. For monogastric animal production, CF can function as an indicator of primary energy use, as both energy use and GHG emissions originate mainly from feed production. It is unclear how the biodiversity impact category correlates to CF. More intensive production can allow more land to be left in its natural state, but can involve increased use of pesticides and fertilisers and monocrop-ping locally, threatening biodiversity. Using CF as an indicator of the environmental impact of meat can generate conflicts with other environmental categories in some cases. However, the risk of damaging other environmental areas when acting on CF must be weighed against the risk of further neglecting to act on global warming by failing to exploit the current market momentum of carbon footprinting.