Methane, a greenhouse gas emitted in large quantities by ruminant livestock, causes strong short-term warming but does not accumulate in the atmosphere like carbon dioxide. Achieving “net-zero warming” rather than “net-zero emissions” therefore requires a focus on ambitious mitigation of long-term pollutants. This presentation will summarise recent advances in the measurement of the relative contributions to warming of short- and long-lived greenhouse gases and how this knowledge may support the development of effective mitigation policies.

In this context, the discussion will also present the interim results of the Greenhouse Gas Instruments and Policies (GRIP) project from the Institute for Science Innovation and Society at the University of Oxford. The GRIP project has undertaken over fifty hours of interviews with expert stakeholders (policymakers, politicians and representatives from academia, industry and civil society) in the United Kingdom on greenhouse gas removal, to better understand views on how policy should be developed to either restrict or incentivise proposed techniques to remove greenhouse gases from the atmosphere.​

The side event will also discuss the importance of greenhouse gas metrics for national level emission accounting, in the context of the New Zealand Government’s proposed target of net-zero emissions by 2050. Under conventional metrics, emissions from agriculture make up around half of New Zealand’s total emissions. Despite this, the ‘biological emissions’ from agriculture – methane and nitrous oxide – have not been included in New Zealand’s emissions trading scheme or other measures, beyond reporting obligations. This presentation will outline some of the main policy challenges facing the agriculture sector, informed by the latest research on the measurement of the various greenhouse gases. A key component is how to differentiate between long and short-lived gases in policy and economic instruments.