Food production and land use must shift to meet climate targets

The more trees we plant, the more emissions headroom we get for livestock

Nothing less than a transformation in land use and agriculture practices and policies will be needed for Ireland to meet its target of becoming a climate-neutral society by 2050. At that stage, any remaining emissions would be balanced by carbon removal by trees, soils and so-called “negative emissions technologies”.

Emissions from agriculture, responsible for over one-third of our total emissions, rose much faster than other sectors over the past decade, mainly because of growing dairy output in anticipation of the removal of milk quotas in 2015.

Agriculture has been set less ambitious emission targets than other sectors. The latest food industry strategy adopted by the Government – Food Vision 2030 – has targeted a cut in emissions of 18 per cent by 2030, but much greater ambition will be needed. Otherwise, emissions from the rest of society would have to fall by 70 per cent to meet the overall national target, a virtually impossible task in eight years.

Ireland is a heavyweight in food production and we specialise in exporting some of the most carbon-intensive foods. Neither short- nor long-term climate targets will be met without changes to how we produce food and manage land.

Furthermore, international pressure is mounting for stronger cuts. Recent UN reports have brought attention to methane, a potent but short-lived greenhouse gas largely arising from food systems and ruminant animals like cows. Rapid cuts in methane emissions are necessary to meet the Paris Agreement goals, according to climate scientists, and are the strongest lever we have to limit global warming in the short term.

Some claim the impact of methane emissions is overstated. While it’s true that methane emissions don’t need to fall to zero, as CO2 emissions do, simply stabilising methane emissions is not an adequate response to climate change.

Even though it is short-lived, methane is a turbo-charged greenhouse gas, which is true even if it arises from animals (so-called “biogenic methane”). Human activities have caused its concentration in the atmosphere to rise by 150 per cent, causing half a degree of global warming already. If we only cared about the global temperature in the distant future, there would be a case for merely stabilising methane emissions, but with worsening extreme weather events this summer, and rapid glacial melt already attributed to climate change, the time for treating global warming as a problem for the future is over.

Methane emissions

In response, the US and EU have pledged to reduce methane emissions by 30 per cent by 2030, and Denmark, which also has a large dairy sector, plans to reduce its agriculture emissions by 55-65 per cent by 2030 from 1990 levels, rewilding some farmland and compensating farmers with $600 million during the transition.

Some argue that if we counted the CO2 drawn down from the atmosphere into trees and soil, so-called “land use removals”, the climate impact of our agricultural sector would not seem so bad.

Grassland on drained organic soils and degraded bogs emit about 10 million tonnes of CO2, about the same as the power sector each year

In fact, the opposite is true.

In Ireland, land is a significant net source of nearly five million tonnes of CO2 emissions. Grassland on drained organic soils and degraded bogs together emit about 10 million tonnes of CO2, around the same as the power sector, each year. These are partially offset by forestry and grassland on mineral soils, which draw down and remove CO2 from the atmosphere.

It is not credible for the agriculture sector, therefore, to claim credits for CO2 removal from trees and soil without also addressing the very significant sources of land-use emissions.

Moreover, forests will remove significantly less CO2 from the atmosphere over the coming decade and could even become another emissions source by 2030, according to projections. We have simply not been planting enough trees: annual planting is 60 per cent behind the Government target of 8,000 hectares.

Even if tree planting accelerated immediately, CO2 removals would mainly accrue after 2030, because trees only begin to sequester carbon in earnest when they are mature. This means that there is little scope for land to contribute to meeting the 2030 target.

‘Carbon farming’

There is also hope that targets can be achieved by drawing down CO2 into the soil through new practices known as “carbon farming”. This could play an important part in climate mitigation efforts, but the capacity for soil to permanently sequester carbon is uncertain, and the changing climate may alter the ability of the landscape to absorb carbon. Drought and changes in land management can cause dramatic and sudden shifts in the carbon cycle, making it very difficult to establish that permanent carbon removals have taken place. The same is true for forests. For example, a devastating outbreak of bark beetle linked to climate change has destroyed large swathes of central Europe’s spruce forests, decimating its carbon sink.

The capacity for soil to permanently sequester carbon is uncertain, and the changing climate may alter the ability of the landscape to absorb carbon

Independently verifying that removals are permanent and additional to existing climate measures for land is not only scientifically uncertain, but bureaucratic and costly.

This means there is very limited, if any, potential for land-use removals to mitigate the need for rapid emissions reductions.

Looking out to 2050, the only large potential for agriculture and land use to reach net-zero is – on top of maximisation of emissions reductions – rewetting drained organic soils and balancing remaining emissions from livestock by sequestering CO2 in trees. It could take a sustained effort of planting 20,000 hectares per annum from now to 2050 to sequester enough CO2 to balance even half the current rate of emissions, according to research led by Dr David Styles at the University of Limerick. Looked at in another way, the more trees we plant, the more emissions headroom we have to maintain livestock.

Given the twin crises of biodiversity and climate change, we need to treat forestry as a space for nature to thrive and as part of our natural heritage, not just as a CO2 sponge and source of fuel and fibre. After all, Ireland’s native landscape is temperate rainforest, not grassland, and protecting and expanding the small precious pockets of what remains should be a top priority.

There are now few deniers of the need for rapid action to halt the irreversible damage we are inflicting on future generations through greenhouse gas emissions. When making such plans, the targeted reductions for each sector must be proportionate to the damage they are doing, and there are no silver bullet solutions to reducing emissions from the agriculture sector. Action is needed for change to happen.

Dr Hannah Daly is a lecturer in sustainable energy at University College Cork, ERI and MaREI Centre