Reducing greenhouse gas emissions from livestock: the costs


The livestock sector is estimated to contribute 14.5% of all global anthropogenic greenhouse gas (GHG) emissions. This study, taken from a recent Science for Environment Policy briefing highlights some of the work that is going on looking to quantify the benefits of adapting management practices to reduce emissions and which may be suitable for policy targeting and intervention. The information below is a summary of the work, but to read the full article please click here.

Globally there is the potential to reduce GHG emissions from the livestock sector by as much as 2.4 metric gigatonnes of CO2 equivalent emissions every year (a value that is incredibly hard to visualise or get your head round, but its big). The vast majority of this potential is associated with ruminants and comes from management such as improved production efficiency, and the use of feed additives or other products to suppress methane production, or measures designed to improve the carbon sequestration potential of the system through improved grassland management and the inclusion of legumes within forage mixes.

Until now, there has been little research that has tried to assess the costs and benefits of different practices designed to reduce emissions. Those studies that have tried have suggested that there is a proportion of this potential is available at a price, but that much of the options available are not attainable in a cost effective manner.

This project tried to dig a bit deeper into the statement above and tried to estimate the costs of reducing GHG emissions from the livestock sector globally. The results in this work looked at the marginal costs (defined as cost of producing one more unit and include all the costs associated with producing that unit), rather than the commonly reported average costs of abatement as such allowed for variability in the effectiveness of practices depending on the region and production system being reported.

What did they do?

This study used a 5 step analytical approach:

  1. Focussed on ruminant production systems (which account for over 90% of all direct GHG emissions from livestock globally) 
  2. Then they looked at management practices according to their reliability and effectiveness at reducing emissions (no good looking at options that weren't going to achieve the desired outcome) 
  3. They also focussed on practices that targeted methane and carbon sequestration (rather than nitrous oxide) which have been documented as being the largest sources of abatement for ruminant production systems, 
  4. Five practices were looked at - three for methane emissions and two for carbon sequestration 
  5. Data was analysed using a computer model and allowed the scientists to create graphs and curves which allow an understanding of how the costs increase with every additional unit of emissions that is reduced. 

What were the management practices that they looked at?

  • Feeding of dietary oils (reducing methane) 
  • Feeding of nitrates ( in the form of calcium, potassium, or sodium nitrate, fed to reduce methane) 
  • Urea treatment of crop straws fed to animals 
  • Improved grazing management (carbon sequestration) 
  • Inclusion of legumes within mix (again carbon sequestration) 

What did they find?

Soil carbon sequestration The two opportunities to improve soil carbon sequestration were both found to be affordable. The potential of improved grazing management was found to be achievable at no cost to start with, costs did then increase when the opportunities to improve management are exhausted. Therefore ensuring that grassland management is optimal and efficient will help with carbon sequestration, and reduction of emissions associated with livestock production. The inclusion of legumes was found to be affordable and effective. Despite the high upfront costs of establishment they are offset by the returns associated with increased forage production and animal productivity, 85% of its total abatement potential is achievable at a carbon price of $10 t of carbon dioxide equivalent per year.

Reduction of methane emissions The costs of dietary oils and nitrates are high at all levels of abatement due to the expense of oilseeds and lack of associated improvement in animal productivity. The urea treatment of straws were also shown to be unprofitable which is in line with its modest uptake.

What did they conclude?

The study offers guidance for targeting abatement efforts to have the highest impacts at the lowest cost. In western Europe, legume growing was the most efficient practice and, overall abatement practices were found to the most effective for dairy cattle. The study suggests that around half of the abatement potential for improved grazing management and legume sowing could be achieved with extension and capacity building programmes. For the costlier abatement options though, stronger policy options would be required for example a carbon tax or emission quotas.

From the Farm Carbon Cutting Toolkit