Environmental Change Institute, University of Oxford

Cows grazing before Mount Taranaki, New Zealand.

Recent ECI MSc alumna Jessica Zionts (ECM, 2017-18) writes about her experiences at COP24, organising the ECI's side event and exploring how new climate models are changing the debate around livestock emissions.

Having recently completed the MSc in Environmental Change and Management, I was asked to go to Poland to coordinate an ECI side event at the annual UNFCCC negotiations, COP. The event topic, closely related to that of my dissertation, was on the role of greenhouse gas metrics in formulating climate policy to achieve net-zero emissions.

In recent years, the ECI’s Professor Myles Allen and his colleagues have come out with several publications related to this idea. In short, the ECI climate group’s research suggests that warming due to greenhouse gas emissions are more accurately modeled by a new metric called GWP* that accounts for the short-lived properties of methane, as opposed to conventional Global Warming Potential on a 100 year timescale (GWP100).

GWP100 is said to be like “adding your current speed to the distance you have already travelled to get some nonsense measure of ‘aggregate distance-equivalent’.” Essentially it is less effective in conveying the impact of emissions on the atmosphere’s energy balance.

As a result there is an emerging debate over which climate model and metrics should be used in the formulation of climate policy and emissions accounting.

While this particular conversation is slowly gaining traction in the world of climate research, it is highly relevant in heavily agricultural countries where a large portion of emissions come from ruminant methane.

The debate frequently makes headlines in countries like New Zealand, where agricultural methane accounts for nearly 50% of emissions under GWP100. However, according to GWP*, the warming due to methane emissions is significantly less than warming due to carbon dioxide. For this reason, New Zealand has served as a key case study both in my dissertation and in other publications from ECI.

I was intrigued to learn that, beyond the ECI side event, this issue was getting significant attention at COP24. The Pacific and Koronivia pavilion, which served as the hub for New Zealand’s side events, hosted a three-day event called “Act!on Agriculture” during the second week of the conference

I took this as an opportunity to explore some of the perspectives present at COP on the concepts of GWP* and agricultural emissions, as well as to gain a multi-faceted understanding of the significance of metrics within different groups discussing these issues.

“Act!on Agriculture” involved speakers from New Zealand, Ireland, France, Australia, and the Netherlands. The overall goals of the discussions were focused on increasing agricultural productivity, reducing emissions, and improving resilience to impacts from climate change. Throughout the week, GWP* and the notion that methane causes limited warming relative to carbon dioxide were mentioned in passing on only a handful of occasions in the pavilion. However, the attitudes expressed towards GWP* were typically skeptical, and speakers would say that they don’t buy into the new metric because it goes against the message that parties should mitigate.

Beyond the pavilion, at the ECI side event, attendees conveyed similar concerns. One question from the floor suggested that the metric’s use in policy would mean that farmers do not need to reduce emissions. However, panelist and ECI post-doctoral fellow Michelle Cain asserted that “GWP* strongly punishes an increase in methane, and similarly rewards a reduction.”

The objective of the side event was to solidify the idea that it is necessary to have an accurate metric. Additionally, it is scientifically proven that, under scenarios of ambitious mitigation, GWP* is able to more accurately predict warming.

Having worked with Dr. Cain and Professor Allen, I was familiar with their positions on the matter prior to COP. In an effort to expand my horizons, I met up with a few New Zealanders, curious about how the GWP* concept has propagated from their perspectives.

Dr. Adrian Macey is the former Chair of the UN climate negotiations under the Kyoto Protocol, and currently serves as an Adjunct Professor of climate policy at the University of Wellington, Victoria. He has worked closely with Myles Allen in communicating the implications of treating methane as a short-lived pollutant.

As a specialist in New Zealand climate policy, he offered unique insights into the attitude towards reducing agricultural emissions in his country. Dr. Macey suggests that, while the momentum of the focus on agricultural emissions “may not be kept up at another COP, the focus on it is a no-brainer because the Paris Agreement means everybody has to make reductions.” He goes on to say that “the tone of the events [at COP] are business-like and positive, and there’s a can-do attitude” towards the commitment to reduce emissions. In general, Dr. Macey conveys that farmers understand their responsibility to reduce emissions.

In addition to farmers and policymakers, environmental NGOs have played a significant role in shaping recent New Zealand climate policy. Victor Komarovsky works with Generation Zero, a youth NGO focused on climate change that is also responsible for New Zealand’s Zero Carbon Act (ZCA), which will go into effect in mid-2019. The ZCA will set a legally binding pathway to achieve zero emissions by 2050.

With this goal, of course, the discussion of metrics comes into play. The ZCA specifies a “two-basket approach,” which means that separate targets will be set for long-lived carbon dioxide and short-lived methane. In this approach, methane does not need to reach zero in order to meet the goals set.

Generation Zero supports GWP* and a two-basket approach. Because of their perspective on the relative warming effect of methane, they are considered as being “very conservative” compared to most environmental NGOs in New Zealand. However, rather than using GWP* to excuse farmers from reducing emissions, Komarovsky suggests that, “the GWP* discussion needs to be framed around not screwing up the planet…, if we reduce methane, we can reduce temperature, and if you can do things to reduce warming, you should.”

While GWP* neither punishes nor rewards stagnant emissions, "in reality the herd is still growing", along with the potential for warming trends to continue due to methane, Komarovsky reminds us. “So the conflict between growth of industry and the need to reduce emissions remains,” regardless of the metric used.

The ECI side-event at COP24.