How climate change finally entered the Irish consciousness
Published 26/12/2015 | 02:30
Until a few years ago, climatologists were loathe to link any extreme weather event to climate change. More severe events could usually be cited from times past, when human impacts on the atmosphere were negligible. Scientifically, it was not possible to disentangle natural from human influences on climate.
Thus, while the frequency and intensity of storms or heavy rainfall is expected to increase significantly as the ocean and air in the vicinity of Ireland warms, pinning down individual events to such factors was considered speculative. However, the science has advanced and in December the scientific journal 'Nature' claimed greenhouse gas loading of the atmosphere had made the flooding event associated with Storm Desmond 40pc more likely.
In many ways, the people of Ireland were ahead of the scientists in realising climate change had come home to roost, and the events of early December merely reinforced their conclusions. The scenes of devastation around Ireland, so reminiscent of a similar event in November 2009, reminded us that established statistical concepts such as the "once in a century event" are flawed as the data calculations on which they are founded are debased by a climate change signal, which awakens us to a new reality of living with, and adapting to, climate change.
In many ways, 2015 had, until early winter, been relatively benign in terms of weather events. Winter 2014/15 was cooler and drier in most parts and was the sunniest winter in Dublin since 1942. Summer, though, was disappointingly cool and wet with the highest temperature anywhere only reaching 25.6C. In the west, over 50 of the days from June to August were wet. Autumn was memorable for its mildness and dryness and as winter approached the jetstream began to deliver Atlantic storms.
Abigail, Barney and Clodagh were quickly forgotten; but Desmond will not. Bringing in its wake an 'atmospheric river' stretching from Ireland to the Caribbean, Storm Desmond dumped over 100mm of rain in many parts and left a legacy of several weeks of flooding. Across the Irish Sea, Desmond broke the United Kingdom's 24-hour rainfall record, with 341.4mm falling in Honister Pass, Cumbria, on December 5. To provide a yardstick, 356.6mm fell in Glasnevin in Dublin for the whole year of 1887.
As a mid-latitude country, Ireland's temperature trends mirror the global average and everywhere in the country is 0.5C warmer than 30 years ago. But averages disguise the day-to-day variations and the current mild winter is breaking long term records. At 4am on December 17 the temperature in Malin Head was 16C, a new December record. Most days in July and August 2015 failed to reach this value at this location.
Tackling climate change in Ireland can only be successful as part of a global effort, and this was why 195 countries came together in the world's largest summit meeting in Paris this month. Though the agreement provides only a framework, it represents the first step of an increasingly strict diet of measures that will be required over coming years, with each successive five-yearly pledge being stricter than its predecessor.
Ireland will have to play its part in meeting its EU obligations and also contribute much more generously to the developing world in recognition of the harm we have caused by our inaction. We may yet look back on Storm Desmond as a catalyst for change, as the year when we finally realised the cost of inaction in Ireland was a price too high to pay.
John Sweeney, climatologist and emeritus professor of geography, Maynooth University