Context: Climate change and water scarcity are global challenges facing humanity. Animal agriculture generates considerable greenhouse gas (GHG) emissions and consumes large volumes of water from rivers, streams and lakes. Reducing consumption of animal agricultural products with a relatively high carbon or water footprint, such as dairy, is often promoted as a mechanism to reduce the environmental impacts of food production. Attributionally-based footprints do not, however, assess the consequences of a change in demand for a product.

Aims: This study aimed to assess the water and climate change consequences of replacing NSW dairy production, and co-products of dairy production, with plant-based alternatives.

Methods: Process-based consequential life cycle assessment was used.

Key results: Water savings associated with the change would be limited and GHG emissions reductions would be ~86% of that as estimated by the carbon footprint of production. When NSW dairy production was replaced with soy-based alternatives and two GHG emissions reduction strategies were implemented across the industry, namely enteric methane inhibitors and flaring methane from effluent ponds, GHG emissions increased by 0.63 Mt carbon dioxide equivalent when dairy production was replaced.

Conclusions: The environmental benefits associated with replacing NSW dairy production with plant-based alternatives should not be determined by attributionally-based approaches.

Implications: Policies that aim to reduce the environmental impacts of agricultural production need to consider the market effects of a change in demand for products and not rely on estimated impacts of current production.

背景：气候变化和水资源短缺是人类面临的全球性挑战。畜牧业产生大量温室气体 (GHG) 排放，并消耗大量河流、溪流和湖泊的水。减少碳足迹或水足迹相对较高的畜牧产品（例如乳制品）的消费通常被视为减少粮食生产对环境影响的一种机制。然而，基于归因的足迹并不能评估产品需求变化的后果。

目的：本研究旨在评估用植物性替代品取代新南威尔士州乳制品生产及其副产品对水和气候变化的影响。

方法：使用基于过程的后续生命周期评估。

主要结果：与这一变化相关的节水量将是有限的，温室气体排放量减少量将约为生产碳足迹估算的 86%。当新南威尔士州的乳制品生产被大豆替代品取代，并且整个行业实施了两项温室气体减排策略（即肠道甲烷抑制剂和污水池燃烧甲烷）时，乳制品生产被取代时，温室气体排放量增加了 0.63 公吨二氧化碳当量。

结论：用植物性替代品取代新南威尔士州乳制品生产所带来的环境效益不应通过基于归因的方法来确定。

影响：旨在减少农业生产对环境影响的政策需要考虑产品需求变化的市场影响，而不是依赖于当前生产的估计影响。