Irish mineral soils sequestering more carbon than thought
To Might Are Hold Adding Depleting But Soils Stocks? Substantial Carbon, Irish We These Or
Irish mineral soils sequester nearly 4.5 times more carbon than is allowed for in the current measurement of Ireland's greenhouse gas emissions, according to preliminary findings of the National Agricultural Soil Carbon Observatory (NASCO).
But long-term measurements are required to validate these findings, said Teagasc Research Officer Rachael Murphy, at the Counting Carbon: Science and Practice Conference organised by Teagasc.
She also noted high sensitivity to management and climate. For example, conversion of grassland to forage crops at Johnstown Castle in 2005 shifted a site from a net carbon sink to a net source in the following years. Also in the 2018 heatwave, Johnstown Castle grassland transitioned from a net sink to a net source.
It is part of a huge research effort on carbon. The findings will underpin carbon farming, which Department of Agriculture (DAFM) officials at the conference described as an "important enabler for the agriculture and land use sectors to meet Ireland’s climate targets (25% emission reduction in agriculture by 2030)".
They said carbon farming — offering additional income for landowners who remove and store carbon in Ireland's soils, forests, grasslands, croplands, and hedgerows — requires the confidence, verification and certification of a well-functioning National Carbon Farming Framework.
Other speakers detailed some of the research work on climate action and carbon farming.
Teagasc Senior Research Officer Giulia Bondi said Ireland needs measured carbon data for different soils, management practices, and land uses, in order to develop Tier 2 data — more accurate than the Intergovernmental Panel on Climate Change (IPCC) Tier 1 data that Ireland currently uses for calculating soil carbon and emissions.
Ms Bondi said Irish soils have substantial carbon, but are we adding to or depleting these stocks, and how permanent is soil C sequestration, are key questions. She said grasslands usually store carbon, but there is uncertainty about how much, and how management and climate affect this.
Matthew Saunders, Assistant Professor in Plant Ecophysiology at Trinity College Dublin, said peatlands are one of the most important terrestrial carbon stores. But over 90% of Irish peatlands have undergone land-use change. Peat-based grasslands are a net carbon source. Their area is estimated at between 339,000 and 500,000 hectares.
In his presentation on monitoring, reporting and verification of farm carbon stocks, Teagasc Senior Research Officer Stuart Green said it takes up to 30 years for a replanted hedgerow to absorb the carbon lost when the old hedgerow was removed.
Teagasc Livestock Systems Research Officer Jonathan Herron said rapid adoption of existing measures and emerging technologies is urgent for Irish agriculture to achieve its climate targets. This is easier in tillage, but in ruminant systems further carbon removal will be required.
However, Teagasc projects nearly all systems achieving climate neutrality, if there were separate targets for biogenic methane and longer-life emissions. A key criticism of the IPCC’s global warming data is not distinguishing between short- and long-lived greenhouse gases.
Anaïs L’Hôte of the French Livestock Institute said low-carbon agriculture is an integral part of the EU strategy to be the first climate-neutral continent by 2050. She said the European Commission's carbon certification framework should be published at the end of 2024.
That will help to enable carbon farming. Carbon farming to diversify farm income was viewed by 62% as a positive in a consultation launched last September by the DAFM as one of the first steps towards an Irish Carbon Farming Framework.
The consultation included an online survey. The DAFM received 457 responses, 30.6% from farmers, 24.9% from farm advisers, and 18.6% from foresters.
Only 53% said they were willing to join a carbon farming initiative right now. The rest would rather wait, and admit that they do not know enough to be able to decide now.
But there was broad agreement that compensation to reward eco-system services was needed, and strong agreement that carbon removal, greenhouse gas (GHG) reductions, and biodiversity measures be included in the Framework.
Independent governance responsibility was favoured by 44%, with 33% saying the DAFM should provide the over-arching governance responsibility.
A great majority said the State or the EU should pay for framework services. However, a clear group in the consultations believed the costs can be shared by consumers, processors, and food producers.
The DAFM officials at the conference said there is a significant carbon farming knowledge gap amongst farmers, landowners, and agri-food stakeholders. "As a first step, it would be useful to develop a knowledge transfer strategy".
They also said additional funding is needed to develop carbon farming further in Ireland. The consultation revealed a strong consensus that those who have adopted measures early must be recognised.
There was also strong support for a Forestry Carbon Code (akin to the UK Woodland Carbon Code).
On acceptable time horizons for financing activities, a longer duration was considered more acceptable. Close to 50% of responders indicated funding of 20 years was preferred.
