Trials show up to 20pc fall in emissions when plant is added to diet
Scientists are combing the west coast for seaweed to feed to cattle and sheep after research showed the plant, when added to feed, could stop them emitting so much climate-warming methane.
The project, co-ordinated by state agriculture body Teagasc, is tapping into the country’s growing seaweed harvesting industry, which is seeking new markets as it revives centuries-old traditions.
But some are sceptical that the seaweed feed additives – or any quick technological fix – can sidestep the need to reverse a surge in Irish cattle numbers if the country is to help reduce Europe’s largest per capita methane output by 2030.
Around 20 species of seaweed, most from the Atlantic coast, have been tested by researchers, while dozens more have been collected by the project’s partners in Norway, Canada, Sweden, Germany and the UK.
Scientists in the US and Australia have already dem- onstrated dramatic methane-reducing qualities from one seaweed type – Asparagopsis – when small quantities are added to feedstock.
But they have not yet managed to scale up production of the seaweed, which is not easy to grow in north-west Europe.
The Irish project aims to find abundant native seaweeds to use instead, even though the researchers admit they are unlikely to match the reduction in emissions of more than 80pc shown with Asparagopsis.
“We have identified some brown seaweeds that are very positive and they’re producing results,” said Maria Hayes, project lead of the SeaSolutions project.
Her team has achieved methane reductions of 11pc to 20pc in early trials.
“The reductions aren’t going to be a silver bullet, but it can significantly reduce emissions,” she added.
Researchers are also working on how to integrate the feed additives into Ireland’s predominantly grass-based cattle farming system.
On a farm outside Hillsborough, Co Down, researchers use treats to coax cows to poke their heads into a solar-powered machine that measures the level of methane on their breath.
They will test them again using seaweed additives, said Sharon Huws, Professor of Animal Science and Microbiology at Queen’s University Belfast.
“The levels that are used to feed ruminants are very, very small so you don’t need to get a lot of it in order to get an impact,” she said.
The technology has caught the imagination of farming groups and politicians, who insist that stringent targets for cutting greenhouse gases such as methane should not mean a reduction in the size of the Irish farming sector.
However, Sinéad O’Brien, co-founder of Mungo Murphy’s Seaweed Co. based in Galway, is concerned the seaweed emissions story could be used by the beef and dairy lobby to justify the current unsustainable livestock numbers.
“We are now practically out of time to learn the lifecycle of many marine species, including how to grow seaweeds of interest, sustainably, at scale, within the necessary timeframe,” she said. “We have nine years to adapt. If we don’t choose to adapt now, by the time we are forced to, it will be too late.”
After growth of more than 10pc in the past decade, Ireland has 7.4 million cattle and is one of the largest exporters of beef and dairy in Europe.
Its per capita output of methane – which has a higher heat-trapping potential than CO2 – is by far the highest in the EU, the Climate Watch database said.
The colourless and odourless gas leaks from waste dumps, oil and gas infrastructure and the digestive systems of cattle and sheep.
At the COP26 UN Climate Change conference in Glasgow this month, Ireland signed up to a pledge to cut global output of methane by 30pc by 2030 from 2020 levels.
However, government ministers have insisted that will mostly be achieved through a 50pc cut in non-agricultural methane, with a reduction of only 10pc in agricultural methane by 2030.
They point to seaweed feed additives as a way to curb emissions without downsizing the herd – with a reduction in the average age of slaughter of beef cattle and genetics research as other possible solutions.