More milk per cow means more methane gas ‘even if stock numbers stabilise’, says EPA

Emissions of methane from the national dairy herd will increase even if animal numbers remain static, Environmental Protection Agency (EPA) analysis shows.

The agency found that annual enteric methane emissions, released from the gut of animals through belching, increased by almost 20pc per cow over the last 30 years.

A further increase of more than 6pc per animal is anticipated by 2030 and another 5.6pc by 2040.

The calculations mean that the policy of stabilising herd numbers will not work as an emissions reduction measure.

Dairy cow numbers have soared in the last decade and it is national policy to keep expanding production in what is the most lucrative sector of Irish agriculture.

Levelling off herd size is as far as farming bodies want to go in meeting climate action targets. They say greater efficiency in production will achieve emissions cuts.

The Government is also reluctant to push the sector to make actual cuts in herd numbers because of the backlash guaranteed to follow.

The assessment by the EPA’s emissions statistics, however, shows a policy of stabilisation will be ineffective.

“Efficiency as it is talked about in relation to dairy cows means producing  more milk per cow, but the cow produces more methane as it produces more milk ,” said EPA senior manager, Stephen Treacy.

“What efficiency does mean is that it’s producing more and more milk while producing ‘more’ methane.

“So we had a 46pc increase in dairy cow numbers in the last 10 years but a 60pc increase in milk production. The milk production is going up more quickly than the methane but the methane is still going up.”

Agriculture accounts for around one-third of Ireland’s total greenhouse gas emissions and 65pc of the sector’s emissions are methane.

Methane has a much shorter survival time in the atmosphere than carbon dioxide (CO2), the most prevalent greenhouse gas, but while it exists, it causes warming much more rapidly and intensely than CO2.

A sharp focus on reducing methane is expected at COP26, the UN climate summit beginning next weekend.

The issue is hugely sensitive here because since the lifting of EU milk quotas was signalled a decade ago, and implemented in 2015, Ireland’s agricultural policy has been to grow dairy cow numbers, rapidly increase milk production and build a multi-billion euro food export industry based on fresh dairy and long-life milk protein products.

But while emissions per litre of milk have fallen, emissions per cow have grown. The average cow produced 112.58kg of methane per year in 1990 and now produces 133.57kg.

That is forecast to rise to 142kg by the end of this decade and to 150kg by 2040.

Total agricultural emissions, which also include nitrogen from fertilisers, methane from storage of animal manures, and CO2 from fossil fuel use in vehicles, heating and electricity, increased by 1.4pc last year – against the national trend of an overall 3.6pc reduction.

All livestock numbers increased last year with the dairy herd growing by 3.2pc, other cattle by 0.6pc, sheep by 4.8pc and pigs by 2.5pc.

Since 2010, there have been increases of 46pc in dairy cows, 30pc in sheep, 10pc in pigs and 30pc in poultry.

Non-dairy livestock also produce methane from their gut and in their manure but to a much lesser extent than cows.

Mr Treacy said it was clear that global methane emissions had to decline.

“It’s not sustainable to continue to expand when we don’t have a solution for how we’re going to tackle the environmental damage,” he said.