This is not to single out Ms Donnelly. Dr Gerard Fleming, its head of forecasting and forecaster Evelyn Cusack have both been at pains in their recent public utterances on the almost unprecedented series of December flooding events to ensure no one could form the impression this latest freak weather is part of any larger pattern, or, heaven forbid, be actually be precisely what we can expect from climate change - Think or Swim Blog.
But natural climate variability means there are plenty of local or temporary events – such as cold winters – that appear to contradict the warming trend. Some years see smaller pressure differences than normal – a condition scientists call the negative phase of the North Atlantic Oscillation (NAO). This causes the jet stream to weaken and to shift south to the Mediterranean, cutting off our supply of mild, Atlantic air and allowing more frequent incursions of cold air from continental Europe and Russia.
Scientists are still investigating what causes the negative NAO that brings us cold winter weather. Studies show an influence on the NAO from El Niño and La Niña – the spreading of warmer- or cooler-than-normal waters across the equatorial Pacific that is known to influence global climate patterns. There's also evidence that low phases of the sun's 11-year activity cycle might influence the NAO and thus bring cold winters to Britain - The Guardian, December 2011.
So Natural Variability is responsible for cold dry weather, but Climate Change is responsible for warm wet weather. Alarmists want to have their cake and eat it. Anyone keeping an eye on the jetstream can tell you that the recent mild December was 100% due to changes in the jetstream that brought warm air from the Equator to Ireland. This is in stark contrast to the past few winters when the jetstream was bringing cold Arctic air.
|Jetstream brought warm air from the Equator in December 2015|
|December 2014 - the jetstream was bringing cold Arctic air to Ireland|
The floods in the Shannon and elsewhere have occurred in the recent past, namely - 1923, 1924, 1928, 1929, 1930, 1938, 1946, 1947, 1949 and 1950. Therefore, serious flooding in Ireland was a one-in-three-year-event from 1920 to 1950.
Its guidance on the IPCC science on emissions and, in particular, the need for ‘Early action…to reduce the chances of dangerous climate change’ is clear and leaves little room for the peddling of dangerous nonsense which, regrettably, still passes for discourse on climate change in parts of our media, most notably RTE’s flagship current affairs programme, ‘PrimeTime’. Its show, broadcast on December 3 last, under the title ‘The cost of climate change’ featured a studio ‘debate’ so badly skewed and so blatantly misleading that, were it about almost any other subject than climate change, the editor of PrimeTime would by now be busy updating his CV for the 2016 jobs market - Think or Swim Blog.
However, this is what the IPCC actually has to say about flooding :
So Met Eireann are quite correct not to attribute the recent floods and wet weather to the bogeyman of "climate change". If climate change is occurring it will be a slow gradual process over many decades, with very slight gradual changes in temperature and weather. The problem for this theory is that there is not, as any scientist will tell you, a linear link between CO2 emissions and temperature increases. Instead, it is a logarithmic relationship, meaning that most of the warming due to CO2 emissions had already occurred before man discovered how to use fossil fuels.
In summary, there continues to be a lack of evidence and thus low confidence regarding the sign of trend in the magnitude and/or frequency of floods on a global scale - IPCC, 2013, p.112.
And what is the trend for winter weather in recent times ? An analysis done in a previous Irish Energy Blog article shows that in five of the past seven winters (from 2009 to 2015), temperatures were below the long term average and the climate was drier than average.