Farmers need clarity on actions for net zero

Mar 26 2024 Posted: 15:29 GMT
  • Researchers urge clear climate policy in the interests of just transition for farmers
  • Land use scenarios identify need for more forests and wetlands and fewer cows and sheep

Lack of consensus on how to account for powerful greenhouse gases from agriculture is impeding policy development for net zero climate targets to ensure a just transition for farmers, the authors of a new scientific study have said.

Many countries have signed up to net zero climate targets by 2050 - less than 26 years from now – which means no longer adding to the total amount of greenhouse gases in the atmosphere in a bid to limit global temperature rise to 1.5°C.

What this means for one of the main contributing emissions, carbon dioxide (CO2), is very clear, the study led by researchers at University of Galway notes.

However, the team say their findings raise concerns over significant gaps in how countries should tackle powerful greenhouse gases which are intrinsically linked with farming - nitrous oxide (N2O), often considered a forgotten greenhouse gas, and methane.

In the study, published in Nature Communications, Earth & Environment, the researchers analysed 3,000 scenarios of agricultural activities and land uses in Ireland out to the year 2100, using 10 definitions of net zero while also accounting for future emissions reductions via farm management and new technology.

In order to meet targets using any of the definitions of net zero, the analysis found:

  • Transformation of Ireland’s agriculture and land sector is required, involving ambitious tree planting and wetland restoration.
  • The increased biodiversity is needed alongside technical abatement measures such as low emission slurry spreading and anaerobic digestion of manures.
  • Land use scenarios that achieved net zero had larger areas of rewetted peat soils, more than double the current area of forestry, and substantially lower meat and/or milk outputs relative to 2021.


  • Maintaining milk production close to 2021 levels would require a reduction of up to 97% in suckler-beef output.
  • Net zero definitions requiring the least dramatic changes in agriculture and land use include those focussed only on carbon dioxide – meaning no targets for nitrous oxide and methane - or those based on an alternative accounting approach (“GWP*”) that attributes a “cooling” effect to a reduction in methane emissions.
  • Net zero definitions requiring the most dramatic transformations - eg the largest reductions in milk and beef output - were those based on the long-term offset of cumulative emissions between 2050 and 2100 and those based on Irish methane emissions being capped based on a per-capita “fair share” of “allowable” global methane emissions.


Colm Duffy, Research Fellow at University of Galway and co-lead author, said: “Our study shows just how much the national interpretation of net zero could shape Ireland's future landscape, with implications for the environment, the economy and rural communities. Choices that may seem difficult now will only become more difficult with delay - clarity is urgently needed to plan a just transition”.

David Styles, Associate Professor at University of Galway and study coordinator, said: “For carbon dioxide, net zero represents a clear, absolute target that is invaluable for strategic decision making. Including nitrous oxide and methane emissions from agriculture in national climate targets is crucial, but lacks consensus and involves contentious value judgements. Some targets may be perceived as unfair to Ireland, given that they either don’t take into account the distinct warming effect of methane through time, or they disregard Ireland’s outsize contribution to global milk and beef production. Other targets may be perceived as unfair by other countries because they allow Ireland to maintain disproportionately high emissions of methane (and nitrous oxide).”   

George Bishop, Postdoctoral Researcher at University of Galway and co-lead author, concluded: “Actions like planting forests take time to deliver benefits. Delaying decisions due to fuzzy net zero goals makes the challenge harder, but also risks missing out on economic opportunities that can support a just transition. A clear vision for a net zero agriculture and land sector is desperately needed to inform strategic decision making by farmers and other stakeholders. This vision must be founded upon a robust and internationally-defendable definition of net zero.”

The question of net zero and how to define strategic policy to achieve the targets has profound implications and the “what, where, and how” of future sustainable food production, peatland management and tree planting – actions that farmers will be expected to deliver.

The issue is acute for Ireland, where more than 40% of greenhouse gas emissions originate from farming and land use, largely in the form of methane and nitrous oxide.

The researchers also noted that policy on net zero should not just be about 2050. Some definitions consider the long-term warming impact out to the year 2100, which is vital to ensure that achieving net zero can be sustained beyond mid-century.


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