A double win: new pathways to reduce greenhouse gas emissions and improve water quality in New Zealand

Abstract

This paper explores potential land-sector policies and practices that could help meet New Zealand’s 2030 Paris Agreement target of reducing their greenhouse gas emissions by 30% from 2005 levels while simultaneous achieving improvements in freshwater quality. We use an integrated model of the country’s agricultural and forestry sectors to explore the economic and environmental outcomes for 21 freshwater and climate change policy alternatives and mitigation target scenarios. The agri-environmental model estimates are then included in a multidimensional decision space framework that incorporates the risk attitude of policy-makers and uses an ordered weighting average model to evaluate potential policy pathways. We find policies that feature afforestation of marginal land are often preferred over because they provide a range of co-benefits such as carbon sequestration and reduced sedimentation and nutrient loss at relatively low cost. On the contrary, policies that only target a specific practice or pollutant are often less preferred because they fail to provide ample spill overs relative to their cost savings.

Keywords

• water quality
• forest carbon sequestration
• primary industry
• land use
• abatement costs