New Zealand has introduced a new bill that aims to bring emissions of long-lived greenhouse gases to net zero by 2050. A separate target has been set for methane emissions from agriculture, with planned cuts of 10% by 2030 and 24% to 47% by 2050.

This paper, by John Lynch of the University of Oxford’s LEAP project, finds that carbon footprint studies of beef cattle typically do not report separate values for emissions of different greenhouse gases such as methane and nitrous oxide. Instead, studies generally report only an aggregated figure in the form of the 100-year Global Warming Potential (GWP100) as CO2-equivalent.

This paper, by researchers from the University of Oxford’s LEAP project, models the climate impacts of beef cattle and cultured meat over the next 1000 years using a climate model that treats carbon dioxide, methane and nitrous oxide separately, instead of using the widespread Global Warming Potential, which assigns a CO2-equivalent value to each greenhouse gas according to warming caused over a specified timeframe.​

This paper uses economic models to calculate the extent to which both supply-side and demand-side measures could reduce non-CO2 greenhouse gas emissions from the agricultural sector, depending on carbon price.

Rice cultivation emits methane and nitrous oxide, which are both more potent greenhouse gases than carbon dioxide. Policies to reduce methane emissions from rice farming generally recommend using intermittent (as opposed to continuous) flooding. However, intermittent flooding could produce much higher nitrous oxide emissions than continuous flooding, according to a recent paper.

New Zealand’s Parliamentary Commissioner for the Environment has released a report exploring how much and over what timescale the climate is affected by methane emissions from livestock. It focused on two questions. First,if methane emissions from livestock were held at current levels or followed business-as-usual trajectories, what would their contribution to future warming be? Second, what reduction in methane emissions from livestock would be needed so that they cause no additional contribution to warming?

Researchers have warned that a cascade of positive feedback loops could push global temperatures into a “Hothouse Earth” state for millennia, even if human greenhouse gas emissions are reduced. Some systems, such as ice sheets, forests and permafrost, could pass a temperature tipping point beyond which they rapidly become net contributors to climate change. If one is set off, the warming produced could trigger the remaining tipping points, like a line of dominoes.

A paper proposes a new method for evaluating the climate impact of short-lived greenhouse gases (GHGs) such as methane. Different GHGs are currently assessed on the basis of global warming potential (GWP), calculated as carbon dioxide equivalent, usually over a 100 year time horizon. The paper authors say that this misrepresents the impact of short-lived GHGs, because they have stronger climate impacts shortly after being released and lower impacts after being in the atmosphere for some time.

This paper examines some of the environmental trade-offs associated with using multilayered biodegradable packaging made of thermoplastic starch and polyhydroxyalkanoate.