Dr David Styles, lecturer in UL's School of Engineering, offers a non-farming view on future actions open to Ireland's dairy sector
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Analysis of agriculture and land use will have a vital role to play in humankind's balanced efforts to reduce carbon emissions, one of many sectors with a part to play. Picture: iStock

Irish dairy farmers have a role to play, along with wider agriculture, forestry and, of course, other industries and society as a whole in Ireland’s climate control targets, writes Dr David Styles, UL-based lecturer in Engineering.

Efficient milk production

Irish dairy farmers, and their cows, do a fantastic job of converting water (rain) into milk, via lush green grass, with the help of various inputs including fertilisers and supplementary feeds.

Most of this milk is processed into cheese and milk powder for international export, allowing the seasonal pattern of grass growth to be exploited through spring calving.

Consequently, Ireland’s dairy sector is booming as a comparatively low-cost and low-carbon global supplier of dairy commodities. Origin Green has been highly successful in documenting and marketing the internationally competitive (comparatively small) carbon footprint of Irish milk production.

Meanwhile, Teagasc’s Marginal Abatement Cost Curve (MACC) has identified a further 9-15% of reductions in greenhouse gas (GHG) emissions from agriculture that could be realised over the next decade, and Ireland’s permanent pastures and hedgerows maintain huge stores of carbon in mineral soils.

Furthermore, improved scientific understanding of methane’s contribution to long-term climate warming mean that emissions of this gas (60% of agricultural GHG emissions) need “only” be reduced by around 50% globally to stabilise the climate.

So, in terms of relative GHG efficiency, Irish milk production scores well, and this fact has been used to justify plans for continued expansion of the sector. But how does this rosy perspective fare when looking ahead to the target for a climate-neutral economy by 2050 — or indeed to the more immediate target of a 51% reduction in national GHG emissions by 2030 contained within the Climate Action and Low Carbon Development Bill?

A question of balance

The first thing to note is that both the 51% national target for 2030 and the climate neutrality target for 2050 relate to absolute emissions. Whilst the average carbon footprint of Irish milk production has decreased by approximately 10% over the past decade, national milk output has risen by almost 50%, and overall agricultural emissions have increased by 12% to 20 million tonnes of CO2 equivalent annually (33% of Ireland’s overall emissions).

A visualisation of the SeQUEsTER project, identifying pathways towards carbon neutrality in Ireland’s agriculture and land use sector. As well as his role in UL, Dr David Styles also leads the SeQUEsTER project.

Whilst past climate action has focused on reducing carbon footprints through efficiency measures, the climate emergency has focused governments, companies and investors on the need for dramatic cuts in absolute GHG emissions at corporate and national level, necessitating a focus on activity levels as well as carbon footprints.

So, what could this mean for Irish dairy farmers? In essence, it comes down to a shift away from a sole focus on efficiency, to consideration of balance across the wider agriculture, forestry and other land use (AFOLU) sector….

Ambitious land management Achieving climate neutrality by 2050 in line with the Paris Agreement will require the AFOLU sector to be a net sink of CO2. Despite huge carbon storage within Ireland’s soils, forestry and land use together actually emit over 3 million tonnes CO2 net annually because of low forest cover (11% of land), exploited peat bogs and drainage of around 350 kha of organic soils under grassland. Climate neutrality in Ireland will therefore necessitate huge action in the AFOLU sector.

Between 0.6 and 1.1 million hectares of grassland will need to be either rewetted (to tackle 9 million tonnes CO2 emitted annually from exploited bogs and organic soils) or planted with trees (to actively remove CO2 from the atmosphere). Some of these activities may need to occur on dairy grassland, in particular to deliver biodiversity and water quality co-benefits.

And the success of these activities in reducing and offsetting emissions will determine the sustainable ceiling for future dairy activity. For example, each kg of nitrous oxide emitted (from fertiliser use, manure management & grazing animals) incurs 260-300 times more warming than one kg of CO2.

Even under an ambitious scenario for 2050 where emissions of nitrous oxide are reduced by 50%, and over 250 kha of drained organic soils are rewetted, over half a million hectares of new forest would need to be planted to ensure that AFOLU emissions of nitrous oxide and CO2 are offset.

Despite some uncertainty around the magnitude of emissions from land use, it is clear that sustainable dairy expansion is contingent on:

(i) a substantial reduction in the suckler-beef herd (partially replaced by fattening the one-third of dairy calves currently exported);
(ii) dramatically improving farm nitrogen balances, driving down nitrous oxide emissions by 50% or more;
(iii) rewetting at least 250 kha of organic soils by 2050; (iv) initiation of an ambitious forest planting programme within the next 5 years, with planting rates of at least 20 kha per year sustained through to 2050.
Thinking ahead to climate neutrality, therefore, requires much higher levels of ambition than currently outlined in the Agricultural MACC or AgClimatise, but also presents opportunities for diversification.

For example, renewable energy generation with anaerobic digesters, and provision of ecosystem services (including carbon offsetting), biomaterials and bioenergy from a mix of forestry and perennial crops.

Opportunities will manifest as CO2 credit prices rise, but orderly transitions delivering multifunctional outcomes will require coherent and proactive national land use planning.

A fair share of methane

The aforementioned land use GHG balance excludes methane on the assumption that separate targets will be set for emissions of this gas in future, in recognition of its short lifetime in the atmosphere.

Global methane budgets compatible with climate stabilisation require cuts of 24-47% relative to 2010 emissions (in Ireland, emissions have increased by 14% since 2010).

A recent study has explored how the global methane budget could be downscaled to national “quotas” for four example countries (Brazil, France, India and Ireland) based on alternative approaches: equal percentage reductions across countries; equal per capita emissions; emission reductions proportionate to GDP; emissions proportionate to animal protein production in 2010.

Ireland’s “fair share” of methane emissions in 2050 implied cuts of between 30% and 79% relative to 2010 emissions. Whilst reductions in livestock production were necessary to comply with quotas, planting trees on land spared from livestock production could ensure that Ireland and Brazil remain significant milk and beef exporters whilst achieving territorial climate neutrality — helping to feed countries such as India that cannot simultaneously achieve food security and climate neutrality (based on current diets).

An urgent need for balanced and coherent guidance

In conclusion, Ireland’s dairy sector is comparatively efficient, and there’s no doubt that Irish dairy farmers will contribute to global food security for decades to come.

However, there are inherent limits to the scale of this contribution. Sustainable dairy production will require coordinated action across the AFOLU sector to ensure that GHG emissions and removals are in balance nationally by 2050.

National and corporate climate neutrality targets mean that “green” marketing of Ireland’s agri-food products will need to incorporate a comprehensive plan for climate neutrality in order to retain credibility.

A coherent and balanced AFOLU policy is urgently needed to augment dairy farmers’ admirable efficiency drive, steering the sector towards sustainable outcomes and reducing the risk of disorderly contraction in the future.

David Styles is a Lecturer in the School of Engineering at UL, and a member of the Bernal Institute, a multidisciplinary team of world-leading materials scientists and engineers, based in UL.

A farmer’s life is always busy, but when you add in looking after the family and a sideline business as an artificial breeding (AB) technician, with a run that is spread out over many kilometres, it can become a balancing act.

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