A response to Doole and Marsh () article: methodological limitations in the evaluation of policies to reduce nitrate leaching from New Zealand agriculture

A recent paper by Doole and Marsh (2013), questioned the validity of using the New Zealand Forest and Agriculture Regional Model (NZFARM) for New Zealand agri‐environmental policy analysis. We respond to their critique by clearly describing the model structure, explaining the NZFARM parameterisation, calibration, and validation procedure, and presenting estimates from a series of nutrient reduction policy scenarios to highlight the utility of the model. In doing so, we demonstrate that NZFARM generates logical and intuitive results that can be used for robust agri‐environmental policy decision‐making.     

Flood prone risk and amenity values: a spatial hedonic analysis

This study examines the impact of flood‐hazard zone location on residential property prices. The study utilises data from over 2000 private residential property sales occurred during 2006 in North Shore City, New Zealand. A spatial autoregressive hedonic model is developed to provide efficient estimates of the marginal effect of flood prone risks on property prices. Results suggest that the sale price of a residential property within a flood prone area is lower than an equivalent property outside the flood prone area. The flood plain location discount is reduced by the release of public information regarding flood risk.     

Economic Impacts of Multiple Agro-Environmental Policies on New Zealand Land Use

This paper investigates the implications of policy on farm income, land use, and the environment when New Zealand landowners face multiple environmental constraints. It also looks at the interaction between climate and nutrient reduction policy and the extent to which one policy can be used to meet the other’s objectives. We use a non-linear, partial equilibrium mathematical programming model of New Zealand land use to assess the economic impacts of climate and water policies at the New Zealand territorial authority level. The spatially explicit agro-environmental economic model estimates changes in land use, agricultural output, land management, and environmental impacts. The policies investigated include a range of carbon prices on land-based emissions ($0–30/tCO\(_{2\mathrm{e}}\)) as well a range of prices on nitrogen leaching from diffuse sources ($0–30/kgN). We estimate that implementing stand-alone greenhouse gas and nutrient emissions reduction policies for the agricultural and forestry sectors will create environmental benefits outside the scope of the policy. However, not all environmental outputs improve, and net farm revenue declines by between 0 and 11%. Simultaneously implementing the two policies results in the desired goals of reductions in nitrogen and greenhouse gas emissions with a marginal economic burden on landowners (i.e. 1–2% additional loss in farm profit relative to a stand-alone policy).