The hottest June, the wettest July – it seems as if every month produces a new meteorological record, writes BETH O'DONOGHUE
ANOTHER MONTH has passed, another weather record has been broken. Hot on the heels of Met Éireann’s announcement that this June was the warmest in more than 40 years comes news that parts of the country experienced the wettest July in 60 years. It almost seems that every year or month produces a new meteorological record of one kind or another.
A quick check of Irish Timesarticles backs up this observation. Like 2010, both 2009 and 2008 had Julys that were some of the wettest for years. In 2009, November experienced some of the heaviest rainfall in 500 years. The summer of 2006 was the warmest in 11 years, the summer of 2005 was named the warmest in 10 years . . . The list goes on.
How can so many “records” be produced on such a regular basis, and can these statistics be considered in any way meaningful? One explanation for this continual record-breaking is the relatively limited duration of weather records with which to compare new statistics.
“Reliable instruments which provide strictly comparable readings are only about a century in existence,” says Prof John Sweeney of the Irish Climate Analysis and Research Units (Icarus) at NUI Maynooth and one of the recipients of the 2007 Nobel Peace Prize. “For many of the Met Éireann synoptic stations, recordings commenced after the second World War, so it is entirely reasonable that records in a variety of categories will be broken.”
Another difficulty in assessing weather statistics is that conditions vary too much to calculate a relevant national average.
“We can’t give a nationwide average, as situations do vary across the country. We collate all the data from each region and that is then published in our monthly bulletins,” says meteorological officer Anne Marie Hickey. “We note, for instance, temperature was down at this station, lower in this station, etcetera, region by region, and this is then taken into account in our records.”
Met Éireann relies on 14 synoptic stations, where measurements are taken hourly, and a number of manual stations where measurements are taken daily. The variety of timescales used makes it likely that new “records” are continually reached.
The breaking of records on very short-term extremes of weather is not a very common event. For example, the highest and lowest temperatures recorded in Ireland were in the 1880s and have not been exceeded since, according to Prof Sweeney. Monthly averages are much more likely to be broken.
The worry is that, as with other scientific claims in the media, the continual announcement of new “records” will eventually have a detrimental effect on the public’s perception of the dangers of global warming.
“Other scientific claims in the press can rest somewhere between the uncertainty of climate science and a journalist’s attempt to get a scientist to ‘firm up’ on the implications of her results and link them to a wider narrative about the impact of climate change on society,” says Dr Padraig Murphy, research fellow in science communication at Dublin City University.
Yet, without a doubt, global warming is contributing to the records.
“Ireland is 0.8 degrees warmer on average than it was in the middle of the 20th century. So the likelihood of any month breaking the longer-term monthly record has a higher probability than, say, 20 years ago,” says Prof Sweeney.
Additionally, as the climate warms and more energy goes into evaporation, the likelihood of extremes of rainfall becoming more frequent also increases, as proven in research by Prof Sweeney.
Met Éireann’s production of such statistics and records is not aimed at attracting media attention. These statistics are extremely valuable to a range of legal, climatological, engineering, insurance and other professions, according to Hickey.
Ultimately, though, it may be people’s general interest that makes these statistics most meaningful. As Hickey points out, “apart from anything else, everybody likes to talk about the weather. People like to know”.
