By degrees: how climate change is already affecting your farm

Flash flooding in Christmas 2021 saw tillage crops in the South Slob and Inis Slob area of Wexford destroyed. Twenty bridges in the county were damaged by the same floods, with some bridges washed away completely.

Over 90mm of rain, or a month’s rain, fell in just 16 hours, devastating villages and farmland.

Last June, an intense thunderstorm and barrage of hailstones in the Enniscorthy area saw the heads of grain, oilseed rape and bean crops shredded in minutes.

Outdoor strawberry crops were badly hit. The temperature dropped by more than 8°C in just half an hour.

Consistent rain from August onwards resulted in an estimated 5,000ac of tillage crops, much of it in Wexford, remained unharvested last autumn.

In November 2023, potato growers in the same area struggled to salvage spuds from waterlogged fields.

It’s often said that farmers are at the front line of climate change and there’s hardly a farmer in Wexford who would disagree. But while Wexford bore the brunt of these particular extreme weather events, it’s a glimpse into the future for farmers in every county from Cork to Donegal.

Climate change is increasing global temperatures and Ireland’s annual average temperature is now approximately 1°C higher than in the early 20th century.

Sixteen of the 20 warmest years on record happened since 1990 and 2023 set a new record high.

For the first time, Ireland’s annual average temperature was higher than 11°C.

While some might welcome warmer weather and may even dismiss a 1°C change as very small, it has huge implications.

Every 1°C of temperature brings with it a 7% increase in rainfall intensity.

And, as Professor Conor Murphy from the Irish Climate Analysis and Research Unit (ICARUS) in Maynooth University explained at a recent ASA webinar, extreme weather events in Wexford, and more recent flash flooding around Midleton, Co Cork, highlight the vulnerability of farming to current and future climate change.

Intense bursts

“As the atmosphere warms, it increases the water holding capacity and we expect heavy rainfall events to increase,” he told an Agricultural Science Association webinar, explaining that more rainfall will come in intense bursts.

Research by the ICARUS unit shows that in Ireland, global warming is being experienced most acutely in spring, with long-term trends revealing a notable decrease in the number of frosty days when compared to the 1800s.

In fact, some parts of Ireland, particularly the east and midlands, are warming at a higher rate than the global average, while others are warming at a lower rate.

On rainfall intensity, there is a significant increase in the intensity of rainfall events, most pronounced south of a line from Galway to Dublin, according to Prof Murphy.

“Increases in extreme precipitation are evident in our long-term rainfall records. And that has implications for all aspects of Irish agriculture,” he warned.

So what does the future hold for Irish agriculture based on what we know about our warming temperatures?

“That depends on how much or how successful the global community is in reducing greenhouse gas emissions. Every action matters,” said Prof Murphy.

“Early and rapid global action on emission reductions would likely leave an Irish climate at the end of the century that is still broadly recognisable in comparison to today,” he said.

However, delayed action would result in an Irish climate that is “increasingly unrecognisable” as the century progresses.

If climate action is taken early, temperatures across the island of Ireland would probably warm by just under 1°C by mid-century before falling back slightly towards the end of the century.

However, if action is delayed, temperature increases could be almost 3°C warmer than the recent past. Intense rainfall and other precipitation events like hail will become more frequent and extreme in most regions of Ireland. The warmer it gets, the more frequent and extreme these weather events will become.

“Storm surges and extreme waves will pose an ever-increasing threat to Ireland as sea levels continue to rise. Again, that threat will increase the more the planet warms,” he said.

Winter rainfall levels in Ireland would increase by 10% to 15% in the next 75 years under a mid-level action, but if action to curb greenhouse gas emissions (GHGs) is late, Irish farmers could face winters that are 20% wetter than we do now.

The number of days with more than 20mm of rain falling in 24 hours would also significantly increase by the end of the century.

Conversely, higher temperatures would see summers become warmer and drier.

“When it comes to agriculture [impacts], it’s drying in summer, increases in temperature resulting in increasing magnitude and length of droughts, particularly in late spring into summer,” Prof Murphy warned.

The key impact of climate change on agriculture is how it will affect key crops, the professor noted, saying that there is likely to be an increase in grass growth but a cut in some crop yields such as wheat.

“With increases in humidity, we expect to see increases in vulnerability of potato crops to diseases like blight,” he explained.

The Maynooth University professor warned that warmer winters are likely to cause an increase in existing and new pests and pathogens because they will not be killed off by a cold winter.

“New pests and diseases are also likely to gain increased geographical range and gain a foothold in Ireland,” he warned.

“At present, a relatively small proportion of land is taken up with irrigation but that’s expected to increase in future, particularly as drought and soil moisture deficits increase.

“Changes in rainfall will have impacts for soil management and soil quality, [with] more intense rainfall events increasing nutrient washout,” he added.

Prof Murphy warned that while climate change would positively affect the grass-growing season by making it longer, that advantage could be cancelled out by wetter winters and a decrease in soil trafficability.

He again reiterated the risk of more severe and protracted drought events caused by climate change.

Soil management will be impacted by climate change, with projected increases in both wet and dry conditions in Ireland.

Soil compaction and damage

“Wetter conditions will increase compaction and degradation from vehicles and livestock,” he pointed out, adding that in response to droughts, the restoration of peatland and wetlands, combined with better grassland and cropland management, could increase soil organic carbon content. This has the advantage of increasing the soil’s capacity to store water and retain nutrients.

Overall, Prof Murphy predicted, farm management practices and their timing will change in response to climate change.

Following the record-breaking temperatures and rainfall of 2023, Keith Lambkin, Met Éireann’s head of climate services warned: “Ireland has seen a remarkable year with rainfall and warming at unprecedented levels at times. These record-breaking extremes have knock-on consequences to much of society.

“Past weather events are no longer a reliable indicator of future weather events, but knowing this allows us to better plan and adapt to our changing climate.”

There is a direct link between climate change and its impact on livestock farming, outlined Prof Murphy.

Increasing rainfall can lead to increases in the prevalence of liver fluke and other diseases in cattle and sheep, as well as increasing the risk from exotic pests and diseases.

Schmallenberg virus, which causes foetal abnormalities in cattle and sheep, has already moved from Europe to Ireland. Warmer weather conditions help the midge population that carriers the virus survive for longer.

The recent cluster of cases of bluetongue virus in Kent, England, raised serious concerns that a disease with major trade implications for cattle could be moving up from continental Europe as temperatures increase.

Prof Murphy warned that more frequent and prolonged periods of higher temperatures will increase the potential for all farm animals to experience heat stress.

This has a knock-on effect on fertility, milk production and growth rates.

The 2018 fodder crisis laid bare what Prof Murphy described as a “cascading risk” - where a harsh winter was followed by a very dry spring and summer.

Farmers had limited options to deal with the resulting prolonged drought because much of northwestern Europe was also affected by drought and sources of alternative fodder imports were simply not available to farmers.

“The impact of these events also has major implications for livelihoods for health and wellbeing of those affected,” Prof Murphy pointed out.

A 2018 UCD survey of 17 Teagasc advisers in the Kerry and Limerick region found that the most frequent causes of farmer stress, according to advisers, were, in order of priority: poor weather, inspections, disease, succession, health and death.

While poor weather was the most common issue identified in the survey, further interviews found that fodder issues emerged as the main farm stressor, driven by poor weather.

In purely financial terms, the 2018 fodder crisis cost farmers €500m in higher feed and forage costs.

At the time, ICMSA president Pat McCormack calculated that concentrate feed costs surged by €355m, while forage costs rose by almost €200m and fertiliser costs climbed by almost €70m.

Next week: the animal diseases spreading due to climate change.