Warmer, wetter weather, an increasing number of storms, and a lot less frost and snow were all predicted for Ireland when climate scientists first deployed a supercomputer in 2020 to chart the likely climatic future for the country.
A team based at the Irish Centre for High-End Computing (ICHEC) in the University of Galway have repeated the exercise, processing vast amounts of data.
With unprecedented detail, the data shows all of the above weather changes up to the year 2100 are more likely – and in most cases will be more intense. This coincides with the world getting progressively warmer.
For years, climate scientists have warned about these risks. With ever improving projections and modelling capabilities, they can give information with a higher degree of confidence about what is likely to happen to our weather, with improved accuracy on regional variations.
Extreme events such as flooding, droughts and storms are likely to be a key issue for Ireland under climate change, ICHEC confirms. This gives rise to questions such as how likely are these storms to arise and how prepared can government and society be to deal with them, said lead author Paul Nolan.
The “updated high-resolution climate projections increase confidence in climate projections for Ireland which, if realised, will impact Ireland’s economy, society and environment in dramatic ways”, he said.
The study – funded by the Environmental Protection Agency, Met Éireann and the Marine Institute – addresses a research gap in previous regional climate projections for Ireland which showed large uncertainty for certain projections, notably rainfall.
“It is imperative that planners and policymakers are adequately informed about future climate change so appropriate mitigation [cutting of emissions] and adaptation measures [adapting to what is expected] can be implemented. This research will inform national policy and further our understanding of the impacts of climate change at a local scale,” Dr Nolan said.
ICHEC ran a range of models processing data in the form of “an ensemble of regional climate models” on supercomputers to generate “high-resolution climate projection data”.
This allowed for a more detailed assessment of potential regional and local effects of climate change. Global trends were also factored in, as were a range of carbon emissions scenarios.
[ Waiting for Kay 2: Researchers bemoan demise of Ireland’s supercomputerOpens in new window ]
The exercise divided the country into blocks of 4km-by-4km, enabling a “high resolution” evaluation to be generated of what is likely to happen in each area.
They also applied Irish data to a range of global scenarios to further enhance reliability of their projections.
These range from “taking the green road”, where the world shifts gradually, but pervasively, towards a more sustainable path (respecting perceived environmental boundaries) to one marked by lack of ambition and “resurgent nationalism”, more concerned about competitiveness and security, as regional conflicts push countries to increasingly focus on domestic or, at most, regional issues rather than climate change.
ICHEC’s latest findings for Ireland include:
Temperature: Near-surface temperatures are projected to rise by 0.5 to 0.7 degrees (2021-2050) under “a low-emission scenario”, and by 2.4 to 3 degrees (2071-2100) under “a high-emission scenario” – with the largest increases observed in eastern Ireland.
Extreme Weather: Heatwaves are expected to become more frequent, while frost and ice days will decrease. “Rainfall climate is projected to become more variable across extremes”; both dry spells and extreme rainfall events will intensify.
Precipitation: The rainfall climate will become more variable across seasons. Winter and autumn months are projected to become wetter, while summer rainfall is expected to decrease by up to 8 per cent by the end of the century.
Snowfall: Snow is expected to decline sharply, by up to 84 per cent by 2100 under the highest emissions scenario. Despite the current cold spell, snowfall is expected to decline by 31 per cent from 2025 on.
Growing seasons: Length of the growing season is projected to increase, benefiting agriculture with warmer soil temperatures and improved conditions for crop production.
Energy: Onshore wind energy potential is projected to decrease, particularly in summer, while solar power is expected to decline across all seasons.
Heating demand: With warmer winters, heating demand in Ireland is expected to decrease over coming decades.
[ How a hotter world is affecting Ireland in five graphicsOpens in new window ]
The updated research provides higher confidence on likely temperature trends, and a more accurate indication of the degree of uncertainty on rainfall patterns.
“Furthermore, the current report provides projections for additional climate variables and derived metrics that are critically important to biodiversity and to key Irish sectors, including agriculture, health, energy and transport,” Dr Nolan said.
Running such a large ensemble of high-resolution regional climate models is a first for Ireland.
This was a substantial computational task and required extensive use of the ICHEC supercomputer – known as Kay, which is no longer available – and the European supercomputer known as ECMWF over the past four years.
This research provides Ireland with a data resource to explore its future climate while enabling assessment of the scale of impacts across sectors, at regional and local levels, Dr Nolan said.
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