Irish droughts more likely due to climate change - report

Climate change is making Ireland increasingly vulnerable to summer drought by causing higher temperatures to draw more moisture from soils and vegetation, new research has found.

A study of this year's record-breaking summer concludes that human-caused warming has already made extremely high levels of potential evaporation during July around eight times more likely and about 7% more intense.

The researchers say this increased "evaporative demand" significantly worsened the effects of exceptionally low rainfall this summer and contributed to severe soil moisture deficits across parts of the country.

The study, led by researchers at Maynooth University and supported by Met Éireann and Teagasc, examined the extent to which climate change contributed to the exceptional conditions experienced during summer 2026.

Ireland recorded its hottest summer for the second year in succession, with an average temperature of 16.28C.

Fourteen of Met Éireann's 25 principal weather stations recorded their hottest summer on record, while Phoenix Park in Dublin experienced 68 days when temperatures exceeded 20 degrees - four more than its previous record.

This year experienced the driest July recorded in Ireland with just 16.1mm of rain across the month, or about 17% of the 1991-2020 average.

However, the study highlighted an important distinction between the effects of climate change on rainfall and temperature.

It did not find clear evidence that human-caused climate change made the exceptionally low rainfall experienced during July more likely.

Rather, it says extremely dry Julys of this kind appear to be becoming less frequent, although the analysis suggests that when they do occur they could produce even lower rainfall totals.

Instead, the researchers identified rising temperatures and the resulting increase in evaporation as the main climate-related factor intensifying summer drying.

Potential evapotranspiration, or PET, measures the amount of water that could potentially evaporate from soils and vegetation if sufficient moisture were available.

The researchers found human-caused warming has made extreme July PET around eight times more likely and increased its intensity by approximately 7%.

With further global warming, atmospheric demand for moisture is expected to increase further, with July PET projected to rise by almost another 6% above present levels in a world that reaches 3C of warming.

The findings have potentially significant implications for Irish agriculture, which has traditionally depended on relatively predictable rainfall and soil moisture conditions.

The effects were already apparent this summer, particularly in southern and eastern counties.

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Severe soil moisture deficits substantially reduced grass growth, forcing some livestock farmers to provide additional feed and, in some cases, begin using fodder originally intended for the winter.

Tillage and horticultural crops were also affected, while irrigation became increasingly important for potatoes and vegetables.

The challenges posed by the combination of increasingly wet winters and greater summer drying was also highlighted in the study.

Rainfall during the six months from October to March preceding this summer was found to have been made around 35 times more likely by human-caused climate change and approximately 27% more intense.

That encouraged strong vegetation growth before the exceptionally warm and dry conditions subsequently dried out soils and vegetation and made wildfires more likely.

'Stable climate no longer exists'

Dr Claire Bergin of Maynooth University's ICARUS Climate Research Centre said warmer summers could therefore have consequences extending well beyond higher temperatures.

She said Irish winters were becoming wetter, resulting in waterlogged fields later in the season, while rising summer temperatures could then rapidly dry those same fields when rainfall was scarce, reducing grass yields.

The research also found a particularly strong climate signal in this summer's temperatures.

Maximum summer temperatures of the kind experienced this year are estimated to have become around 40 times more likely because of climate change and approximately 1.35C warmer.

The change in overnight temperatures was even more pronounced, with the study estimating that the minimum temperatures experienced this summer have become more than 1,000 times more likely and around 1.4C warmer.

Met Éireann climatologist Paul Moore said the "stable climate of the recent past, under which our modern ecosystem evolved, no longer exists".

The researchers conclude that conditions previously regarded as unusually dry for Irish soils are likely to become increasingly common as global temperatures continue to rise, requiring farmers and other land users to prepare for greater swings between excessively wet and excessively dry conditions.