Calculating the contribution of agriculture to climate change

There were a number of important messages at the IFA climate change conference on Tuesday, but by far the most stark was the extent to which the direction of climate change policy is failing to reflect a better scientific understanding of the issue – particularly the role played by various greenhouse gases (GHG).

The most relevant in the context of agricultural policy is an acceptance that the current rules around how methane is treated in the context of global warming potential (GWP) is no longer appropriate from a scientific perspective. It was a point accepted by Prof John Fitzgerald, chair of Ireland’s National Expert Advisory Council on Climate Change. Unfortunately, despite this acknowledgement, there appears to be an acceptance that nothing can be changed until 2030.

At an international level, this is not a major issue given that for most developed countries, agricultural emissions account for a small percentage of total emissions. For Ireland, where the current methodology indicates agricultural emissions to be accounting for 34% of total, it is a major problem with major economic consequences. We are one of the countries most exposed to what is now accepted as flawed methodology. Just as the corporate tax rate was protected, Ireland must mount a diplomatic offensive to force a rethink at international level as to how methane is treated in the context of GWP.

The scientific basis for changing how we look at methane, by far the largest GHG associated with ruminant agriculture, is detailed by Prof Frank Mitloehner here. While acknowledging the gas as an important climate change contributor, he points to the fact that it is part of a biogenic carbon cycle.

It is a cycle where plants absorb carbon from the atmosphere for it to be converted into cellulose (grass), the most abundant biomass in the world, which can only be digested by ruminants. While the consumption of this biomass by cattle releases carbon into the atmosphere, it is recycled carbon and therefore not comparable to the burning of fossil fuels which emits new carbon.

The introduction of a proper policy framework alongside the application of new technologies was shown to deliver a 25% reduction in methane emissions in California

However, a carbon balance is only achieved where livestock herds are kept constant. Where herds are increasing, new carbon is released. Therefore, Prof Mitloehner still points to the need for farmers to reduce methane emissions from agriculture – whether it is to create the necessary head room to allow for increased food production while meeting reduction targets, or helping to contribute to global cooling.

While the science around calculating the contribution of agriculture to climate change may be evolving, it does not exempt farmers from the need to reduce the environmental footprint of global food production.

The introduction of a proper policy framework alongside the application of new technologies was shown to deliver a 25% reduction in methane emissions in California – delivered mainly through a policy framework that provided incentives for farmers to capture biogas from manures and for it to be converted into natural gas for the transport sector.

Once again, we see the extent to which the introduction of proper policy within Ireland could help position agriculture as part of the climate solution.

Food security is one element within the climate change debate that is often ignored, particularly when taking place in developed countries. However, it was highlighted that the surge in world population in the coming decades would be driven by population growth in parts of the world that have the least ability to feed themselves – mainly Africa and East Asia.

In this context, the risk of mass migration due to food insecurity was identified as a very real threat – once again highlighting the need for a global food policy that supports the production of food in places with the most suitable climate and land type – such as Ireland.