Last week, the UN’s sixth assessment report on climate change made for stark reading.
The Climate Status Report for Ireland 2020 followed days later.
The reports were yet another warning that greenhouse gas emissions need to reduce in order to stop global warming.
One speaker from the Intergovernmental Panel on Climate Change (IPCC) with the UN noted that the message is now getting across, explaining that while it has been clear for decades that the world is warming, it is only in recent years that this message is being listened to.
However, this delay in action now means that significant cuts in emissions, particularly carbon dioxide and methane, are needed to limit warming.
Within the report, it described how extreme weather events can be expected to become more frequent and that severe droughts and heavy rainfall events will make farming more difficult.
However, there are also things that agriculture can do to reduce emissions and to increase carbon storage on farms. Other documents and strategies – like Ag Climatise and Food Vision 2030 – released in recent months and weeks here in Ireland have set out a clear direction of travel for agriculture to become climate neutral.
Greenhouse gases in Ireland
Within the Irish Government’s report on climate, compiled by Met Éireann, the Environmental Protection Agency (EPA) and the Marine Institute, there was a breakdown of greenhouse gases in Ireland.
Carbon dioxide (CO2) emissions are measured at four locations in the Republic of Ireland – Mace Head, Co Galway, since 1992; Carnsore Point, Co Wexford, and Malin Head, Co Donegal, since 2009; and Valentia, Co Kerry, since 2019.
Mace Head is used to measure CO2 concentrations in the northeast Atlantic region and is used for global measurements. Measurements can be taken using satellite but are validated by ground-based measurements.
Atmospheric CO2 measurements at Mace Head were estimated to be at 413 parts per million in 2018 – 50% higher than the pre-industrial era.
The report noted that seasonal variability is evident, as CO2 is taken up by vegetation and varies in the growing and dormant periods. This variability was greater in the northern hemisphere, as there is more vegetation.
Fossil fuel combustion is one of the main producers of CO2, but these emissions are also linked to cement production, deforestation, vegetation fires and land-use changes.
Methane is produced from processes such as fossil fuel extraction, burning and distribution, as well as from wetlands and other natural sources, livestock, waste management and rice growing.
In Ireland, the report attributes 93% of methane emissions to agriculture, 5% to waste management and 2% to the energy sector. Methane (CH4) from agriculture comes mainly from ruminant animals – cattle and sheep – as well as from slurry stored from these animals.
Methane is measured at Mace Head, Carnsore Point and Malin Head. Again, satellite and ground-based measurements are taken.
CH4 emissions remained stable in the late 1990s and early 2000s, according to the report, but there has been a 4% increase in CH4 concentrations since 2007. Methane emissions have been measured at Mace Head since 1987.
Reducing methane emissions
Methane is the main greenhouse gas of concern for Irish agriculture and while there was high confidence in a new metric (GWP*) to measure methane emissions and account for its short life in the atmosphere compared to carbon dioxide, this method of calculation is currently not in use. Either way, methane emissions still need to be reduced.
Improved genetics, earlier slaughter of animals, increased grass and clover intake and forage crop use have all been shown to reduce methane emissions. Irish farmers are actively implementing many of these actions while also looking out for the latest technology.
New technologies that can result in reduced methane are coming down the line, such as feed additives containing seaweed and boluses, but the effectiveness of many of these products is still being examined. Multispecies swards can also contribute to reduced methane emissions, while reducing the need for chemical nitrogen and reducing nitrous oxide and ammonia emissions.
Researchers in New Zealand are examining the effectiveness of a vaccine in reducing methane which is thought to reduce the production of the gas by approximately 20% in ruminant animals.
These technologies will be essential if the livestock sector is to reduce emissions while the herd remains stable.
It is also important to remember the carbon capture that agriculture provides. Crops, hedges and soils can take in and store carbon and it is important that the agricultural sector maximises its carbon storage potential and is recognised for it.
Within the UN’s IPCC report, the regional breakdown for Europe suggested increasing temperatures and lower frequencies of frost. Heatwaves are to become more frequent and more intense. Cold spells and frost days are expected to decrease. The increase in precipitation is likely to be in the winter in northern Europe and rainfall and flooding are expected to increase at global warming levels of 1.5°C in all regions, apart from the Mediterranean.
While the obvious impacts of climate change involve weather, it is also important to remember that climate change impacts on human health and biodiversity.
Extreme weather events result in disruption of habitats and can affect different plant species as well.