Abstract
Under the 2015 Paris Climate Agreement, New Zealand (NZ) committed to reducing greenhouse gas emissions (GHGs): all major government policies should, therefore, consider impacts on the climate. Given that the Ministry of Health (MOH) is currently in the process of updating NZ’s Eating and Activity Guidelines (EAGs) series, this represents a key opportunity for the development of public policy that is inclusive of sustainability considerations. In order to contribute to this effort, this thesis aimed to develop a NZ-specific database of food-related emissions that could be used to both quantify GHG emissions associated with the average NZ adult’s diet, and to model the climate impacts of different dietary scenarios that conform to the EAGs.
A NZ-specific Life-Cycle Assessment (LCA) database, including cradle to point-of-sale emissions estimates for each of the 341 food items included within the most recent NZ Adult Nutrition Survey (ANS), was developed by modifying reference estimates from a UK database according to the NZ context. NZ-specific LCAs were incorporated into the database wherever possible. Diet-related emissions were estimated by combining the modified food emissions database with consumption data from the ANS (2008/09). Dietary scenarios were developed in consultation with the MOH; each scenario’s impact on emissions was modelled by scaling consumption of individual food groups according to EAG recommendations. Results were used to develop sustainability statements for potential inclusion within the EAG series.
Regarding the lifecycle emissions of individual food items in NZ, whole, plant-based foods, including vegetables (1.8 kgCO2ekg-1), fruits (1.2 kgCO2ekg-1), and whole grains (1.8 kgCO2ekg-1), were found to be significantly less emissions-intensive per kilogram than most animal foods, particularly red and processed meats (12-21 kgCO2ekg-1). Daily diet-related emissions for the average NZ adult were estimated to be 6.6 kgCO2e: equivalent to 11% of NZ’s annual emissions on a population-level. Conforming to the EAGs with the least required change to current consumption patterns, was found to equate to a modest GHG emissions savings of 7% (5-11%; 95% UI) for the average NZ adult. Savings of up to 50% were found to be possible with further emphasis on sustainable food choices (mainly via a reduction in animal protein intake), and by reducing unnecessary food waste. If adopted at a population-level, emissions reductions resulting from such dietary change among NZ adults would be equivalent to 18% of the reductions needed to meet NZ’s current commitment under the Paris Agreement.
In developing a NZ-specific LCA database of food emissions, this thesis has allowed Burden of Disease Epidemiology, Equity and Cost-Effectiveness (BODE3) researchers to model the climate impacts of different dietary interventions alongside health-related parameters. Such information is likely to provide additional leverage for instituting policy change in the future. In modelling the climate impacts of dietary scenarios that conform to the EAGs, this thesis has provided evidence for incorporating sustainability considerations within NZ’s dietary guidelines. In light of these findings, an ‘issues-based document’ on the topic of sustainable eating, which is intended to accompany the EAGs online, is currently being prepared for the MOH.