Can a greenhouse gas emissions tax on food also be healthy and equitable? A systematized review and modelling study from Aotearoa New Zealand
Authors: Cleghorn Christine , Mulder Ingrid , Macmillan Alex , Mizdrak Anja , Drew Jonathan , Nghiem Nhung , Blakely Tony , Mhurchu Cliona Ni 
Published: February 2022

Introduction

Policies to mitigate climate change are essential. The objective of this paper was to estimate the impact of greenhouse gas (GHG) food taxes and assess whether such a tax could also have health benefits and reduce ethnic inequalities in health in Aotearoa NZ.

Methods

We undertook a systemised review on GHG food taxes to inform four tax scenarios, including one combined with a subsidy. These scenarios were modelled to estimate lifetime impacts on quality adjusted health years (QALY), health inequities by ethnicity, GHG emissions, health system costs and food costs to the individual.

Results

28 modelling studies on food tax policies were identified. Taxes resulted in decreased consumption of the targeted foods (e.g., -15.4% in beef/ruminant consumption, N=12 studies) and an average decrease of 8.3% in GHG emissions (N=19 studies). Using this review, we conceptualized four scenarios: a GHG weighted tax on all foods; a GHG weighted tax on food groups with the highest 50% of emissions (‘high emitters’); A GHG weighted tax on ‘high emitters’ combined with a fruit and vegetable subsidy; A 20% tax on ‘high emitters’.

The ‘GHG weighted tax on all foods’ scenario had the largest health gains and costs savings (455,800 QALYs and NZ$8.8 billion), followed by the tax-subsidy scenario (410,400 QALYs and NZ$6.4 billion). All scenarios were associated with reduced GHG emissions (between 4.2% and 7.0% of the baseline GHG emissions from food). Age standardised per capita QALYs were between 1.6 and 2.1 times higher for Māori than non-Māori.

Conclusion

Applying taxes that target foods with high GHG emissions has the potential to be effective for reducing GHG emissions and to result in co-benefits for population health. Combining a GHG food tax with a fruit and vegetable subsidy may help reduce the negative effects on household food expenditure of such a tax.

Key messages

What is already known on this topic

Modelling studies investigating the impact of food taxes have shown taxes aimed at high GHG emitting foods reduce consumption of ruminant meats and GHG emissions. No reviews of modelling studies of GHG motivated food taxes have been published.

What this study adds

Modelling studies are reviewed and summarised and used to inform modelling of four GHG motivated tax scenarios. Modelled results identify a tax/subsidy with positive impacts on population health (410,400 total or 93.2 quality adjusted life years per 1000 people over their lifetime), health system costs (NZD 6.4 billion savings), ethnic health equity (health gains were 1.6 times higher for NZ’s indigenous population, Māori than non-Māori), GHG emissions (−4.2%) and cost of diets (−0.5%).

How this study might affect research, practice or policy

Policymakers can use these findings in designing a food tax to benefit both climate and population health, utilising these detailed results on factors that affect population wellbeing.