There are a lot of terms out there in relation to climate change or the environment.

Terminology is returning or being added to farming all the time, although it should be said not all of this new terminology necessarily means a new practice.

Much of what we hear in relation to reducing emissions or improving biodiversity brings us back older methods of farming.

For example, liming and the application of organic manures or seaweed to land were all common practice not so long ago, so in many ways, the advice being given in agriculture today is a reminder of what was carried out in the past.

Likewise, farm-to-farm trade was a regular occurrence, the majority of farms were mixed and able to supply at least some of their own feed or straw, while animals helped to keep the soil in good condition.

So as we move back to some of the older ways of farming, there may be new approaches or terms, but many of the principles remain the same.

To help us all understand some of the common terms being used in the discussions surrounding climate change and the environment, the Teagasc Signpost Programme put together a list of some useful explanations and descriptions and the Irish Farmers Journal added some phrases that we see in the news on a weekly basis.

Climate change

Climate change is a change in climate driven by an increase in global temperatures, caused by emissions of gases such as carbon dioxide, methane and nitrous oxide.

Agricultural gaseous emissions

This refers to greenhouse gas emissions – including carbon dioxide and methane - and ammonia emissions from farming.

Greenhouse gases (GHGs)

The three agricultural GHGs are carbon dioxide, (CO2), methane (CH4) and nitrous oxide (N2O). The main sources of GHGs in agriculture are animals and fertiliser, which, according to the Signpost Programme, account for 64% and 32% of agricultural GHGs respectively.


Ammonia can be released from urea.

Ammonia (NH3) is an air pollutant that affects human health and biodiversity, mainly from storage and spreading of animal manures. It should be noted that ammonia is also released from urea when it is applied at the incorrect time.

Protected urea uses an inhibitor to prevent ammonia loss.

Biogenic methane

Biogenic methane is produced from cattle and sheep.

Biogenic methane is methane produced predominantly from ruminants. It is an extremely potent gas, but can breakdown quicker than other greenhouse gases. Methane is produced in ruminant animals – cattle and sheep – when feed is being broken down. Methane gas is then released through burping.

Nitrous oxide

Nitrous oxide (N2O) is a potent GHG, produced mainly through the application of chemical fertilisers, organic manures and excreta. Nitrous oxide is extremely potent and has been associated with the destruction of the ozone layer, as well as contributing to climate change through global warming. Nitrous oxide is associated with the spreading of calcium ammonium nitrate (CAN) and advice in recent years has seen Teagasc suggest a switch to the use of protected urea to reduce nitrous oxide emissions.

Carbon dioxide

The most common GHG, predominantly produced from the burning of fossil fuels.

Carbon dioxide equivalents

All GHGs (CO2, CH4 and N2O) have different global warming potential (GWP). The emissions of all gases are expressed as CO2 for reporting and comparison purposes.

Carbon footprint

Refers to the amount of GHGs emitted as a result of an activity. The production of every kilogram of milk, meat or grain has a carbon footprint. Carbon footprints are calculated by collecting data on fertiliser use, tillage methods, animal feed use, transport and diesel consumption and electricity use on-farm. The data collected estimates the emissions released to the atmosphere as a result of their use on-farm.

Total carbon emissions

Refers to the total emissions from an activity. For example, the emissions from agriculture milk production on a farm.

Mitigation actions

Actions that farmers can take to reduce GHG and ammonia emissions on farms. These activities may also reduce the impact of farming practices on water quality, for example.

Marginal Abatement Cost Curve (MACC)

The Teagasc GHG MACC sets out a roadmap for reducing GHG emissions, including the associated costs and benefits of these actions. Teagasc also has an ammonia abatement curve, as this is also a significant contributor to pollution, even though it is not a greenhouse gas.

Nitrogen use efficiency (NUE)

NUE measures how much nitrogen brought on to a farm is used by the farm and exported in a product from the farm. It allows farmers to estimate how much nitrogen they lose, which is not used in production. Nitrogen can enter the farm through artificial fertiliser, animal manures or animal feed.

Carbon sequestration

Carbon sequestration is the removal of carbon dioxide by a plant. It can then be stored over a long period of time in our soils, hedgerows and trees. However, it should be noted that this carbon can also be lost through practices like tillage, drainage or even poaching by animals.


Biodiversity refers to diversity in nature from plants and hedgerows to animals, birds and soil microorganisms. Diversity can be improved on farms by having a diverse crop rotation, cover crops, multispecies grassland, diversity in hedging plants and trees. When there is diversity in plant life, it will attract different types of wildlife on to the farm. Diversity in plant life can also help to improve soil health and structure, making soils and crops more resilient in drought conditions.

Soil carbon

Sampling for soil carbon.

Soil carbon is carbon that is stored in the soil. It is directly linked to soil organic matter. Increasing levels of soil carbon can improve soil health as plant material breaks down in the process, which can provide nutrients. This plant material also provides food for insects, worms and microorganisms, which can help with soil health and structure.

Carbon farming

Carbon farming is where someone farms in a way that promotes the storage of carbon on their farm, whether that be by growing cover crops, applying organic manure to land, reducing tillage or introducing clover or multispecies to a grass sward to improve soil health. All of these practices have the potential to increase soil carbon storage. Planting a tree or a hedgerow can also result in carbon being stored.

Carbon credits

In the EU, companies that emit large amounts of carbon must work to reduce those emissions and purchase permits which allow them to emit carbon. A carbon credit is where someone buys 1t of carbon that has been stored, so that they can release 1t of carbon.

For example, a farmer could store 1t of carbon in their soil and get paid for that carbon by someone who is emitting carbon.