A new study from Teagasc has investigated the impact of climate policies on protein security in the Republic of Ireland.

The report, published in the journal ‘Environmental Science and Policy’, found that implementing policies aimed at mitigating climate change in the Irish agricultural sector could increase net protein output.

However, net digestible protein output would increase or decrease depending on the policy pursued.

The study outlined that the main land-based systems of agricultural production in Ireland can currently meet the annual protein requirements of 20 million people.

It could meet requirements of 35 million if protein digestibility (how much of the amino acids present in the protein is left for the body to use after digestion) is accounted for, Teagasc said.

Protein security

The study estimated the net protein output across the dairy, cattle, sheep and tillage production systems in the Republic of Ireland, and protein security defined by the amount of people who could have their protein requirements met by these production systems.

All the results are presented in net terms, i.e., considering protein input (human edible protein fed to livestock) and protein output (e.g. milk, meat, grains).

Results are also presented with and without correcting protein for digestibility.

"Results indicate that, before accounting for protein digestibility, one hectare dedicated to cereal or legume production generates more protein, in net terms, than one hectare dedicated to milk, beef or sheep meat production," Teagasc said.

Researchers said that with digestibility of the relative protein inputs and outputs is considered, "one hectare dedicated to milk production produces less protein than one hectare dedicated to legume production, but more protein than one hectare dedicated to cereal production".

"Notably, the contribution of sheep production becomes positive when digestibility is accounted for," according to the research.

"At the national level, these land-based agricultural production systems can meet the annual protein requirements of 20 million people if digestibility is not accounted for, and of 35 million if digestibility is considered.

"The difference is due to cereal protein having lower digestibility than animal-based protein, which impacts the volume of human digestible protein available in animal feeds.

"The contribution of sheep systems also becomes positive when digestibility is included."

Two scenarios were subsequently modelled in this analysis, investigating the impact on protein output and security out to 2030.

In a ‘business as usual scenario’, based on FAPRI Ireland projections included in the Teagasc MACC analysis, agricultural production levels remain relatively stable, and no major climate-related or trade policy changes are assumed.

This results in a moderate decrease in beef and sheep livestock numbers, and in an increase in dairy cow numbers, the report said.

In the second scenario called ‘climate policy scenario’, agricultural production levels decrease, and climate change mitigation policies are implemented for the agricultural sector.

This leads to a large decrease in beef and sheep livestock numbers, a small increase in dairy cow numbers, and an increase in tillage area.

Protein output

"The business as usual scenario would lead to an increase in net protein output and protein security, both with and without accounting for protein digestibility," the research said.

"Around 369,000 additional individuals could have their protein requirements met, not accounting for digestibility, with the increase in dairy livestock units compensating for the decrease in beef livestock units.

"This figure drops to 193,000 additional individuals if digestibility is accounted for, with the impact of a decrease in beef livestock units being exacerbated if digestibility is included."

Under the climate policy scenario, an additional 488,000 individuals could have their protein requirements met, if digestibility is not considered.

"However, when digestibility is considered net protein output would decrease, with 469,000 fewer individuals having their protein requirements met, leading to a decrease in protein security.

"In the climate policy scenario, animal-based protein is substituted towards plant-based protein.

"However, the digestibility of plant-based protein is around half that of animal-based protein, hence, if digestibility is considered, the increase in tillage area is not enough to compensate this loss."

In this analysis, greenhouse gas emissions would decrease by 1.5 Mt under the business as usual scenario, and by 2.7 Mt under the climate policy scenario when emissions associated with the land use, land-use change and forestry (LULUCF) sector are excluded.

Trade-offs

Marie Merlo, who conducted this research as part of her PhD, said: “This analysis shows the trade-offs involved in implementing climate policies to diversify from animal to plant based protein production in Ireland.

“While the main goal is to reduce farm-level greenhouse gas emissions and reach the target of a 25% reduction by 2030, the impact on protein security needs to be considered.

Merlo said the Republic of Ireland has the ability to meet the protein requirements of four to seven times its own population (depending on whether digestibility is considered).

"Hence, this research also shows the importance of considering protein digestibility," she said.

"Ireland is specialised in milk and meat production, which are protein sources with a significantly higher digestibility level than plant-based protein."

This research was carried out under the U-Protein (Unlocking Protein Resource Opportunities to Evolve Ireland’s Nutrition) project.