By Andrew Hoggard, Federated Farmers President and climate change spokesperson
Very recently a scientific paper was put out looking at the greenhouse gas and nutritional impacts of replacing meat in the average diet. The paper Lifetime Climate Impacts of Diet Transitions, with input from a number of very well respected scientists across a range of fields, found that the emissions reductions for a person who abstained from meat for a lifetime were very small – only 2 to 4%. It also highlighted the risk of them missing out on key nutrients.
It wasn’t so much the findings of this paper that I am most interested or excited by, rather the methodology that went into it. Two items really stick out: firstly, the fact that the paper includes nutrition understanding as well as climate science. Far too often when the subject of agricultural emissions come up, the full picture/understanding is omitted in favour of a narrow, siloed view.
The problem with this approach is that it fails to recognise choices are never as simple as portrayed. For example, if we get rid of all animal agriculture and only have plant-based ag, what happens to all the crop waste? Think of the most common plants we grow for food: how much of that plant is consumed by humans? Quite often, less than half. The rest we can feed to animals, which convert it into edible protein.
Likewise, not all land is suitable for crops, and even with some of it that could possibly be cropped, would it deliver as much nutrients as its current pastoral use, and could the environmental impacts of trying to grow crops on it be higher than its current use?
Farming is a rather complex, interrelated biological process that forces you to consider many things at once. So again it’s great to see a paper which recognises a wide range of impacts from a singular choice.
The second point that really interested me was it’s the first paper I’ve seen that utilises the new GWP* metric when measuring the warming impact of methane. As anyone who may have read any previous columns of mine would know, I have been banging on about this metric for a good three years now, since it first came out. Just to recap – this metric takes into account the relatively short atmospheric life of methane, which the current metric GWP100 does not. GWP 100 thus attributes far higher warming impacts to stable or declining levels of methane emissions than what is actually happening.
Now that GWP* is gaining more widespread acceptance, my question is how we incorporate it into programmes such as He Waka Eke Noa, the Primary Sector Climate Action Partnership, and in statistics, such as the New Zealand GHG emissions inventory. To my mind we have an ideal opportunity to use it alongside GWP100, to be able to give farmers information in both metrics. You might ask ‘why not do away with GWP100?’. Well, because some of our consumers may still want a carbon footprint in the old language, as it were. Also using GWP* will help in better being able to articulate the actual net warming impact of a family’s farm.
GWP* still has a way to go to be adopted internationally by the politicians, but I haven’t yet met a scientist who disagrees with the science behind it, and the conclusion that if the methane across the globe was to reduce by 0.3% per year it would have no additional warming impact. The disagreement seems to be more at a policy level, in terms of: is the current level of methane in the atmosphere the correct one?; do we need to reduce it?; if so, from what sectors?; and then across those sectors, in which countries?
The recent UN report talked about a big 45% reduction on expected 2030 levels to help compensate for ongoing CO2 emissions. But it pushed for the vast bulk of the reductions to be occurring in sectors other than agriculture, and the reductions sought from agriculture seemed to be in activities which aren’t that common in the New Zealand farming context.