Seeking climate salvation from the sea

• Published date: 22 November 2021
• Publication title: Otago Daily Times (New Zealand)

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SCIENTISTS are combing Ireland’s west coast for seaweed to feed to cattle and sheep after research showed it could stop them breathing out so much climate-warming methane.

The project, co-ordinated by a state agriculture body, 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 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 reduce Europe’s largest per capita methane output by 2030.

About 20 species of seaweed, most from Ireland’s windswept 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 United Kingdom.

Scientists in the United States and Australia have already demonstrated 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 northwest 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 80% shown with Asparagopsis.

‘‘We have identified some brown seaweeds that are very positive and they’re producing results,’’ Maria Hayes, project lead of the SeaSolutions project, whose team has achieved methane reductions of between 11% and 20% in early trials, said.

‘‘The reductions aren’t going to be a silver bullet ... but it can significantly reduce emissions,’’ Hayes, who works for Teagasc, Ireland’s Agriculture and Food Development Authority, said.

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, southwest of Belfast, in Northern Ireland, 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, Sharon Huws, professor of animal science and microbiology at Queen’s University Belfast, said.

‘‘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.

Political pressure

The technology has caught the imagination of farming groups and politicians, who...