We face cold future as jet stream goes south
Extremes more likely in future Farmers left counting costs
Published 25/05/2013 | 05:00
There was cold comfort from weather experts as they warned that long chilly spells in spring and early summer could become normal in the future.
As the country continues to shiver towards the end of May, farmers have been left counting the cost of an unseasonably cold spring.
Farmers have been forced to import fodder from Britain and France to keep their cattle alive.
And clothes shops have already started stocking their autumn and winter collections, as summer clothes fail to sell, according to fashion consultant Eddie Shanahan.
The country's leading climatologist, Professor John Sweeney of NUI Maynooth, offered scant consolation yesterday as the chill winds continued to blow.
Prof Sweeney, a member of the UN's Intergovernmental Panel on Climate Change, said we could expect more of these extreme cold snaps in future.
He said our weather was being influenced by the jet stream, the meandering high-altitude river of air that typically steers milder air towards Ireland at this time of year.
"The jet stream has shown a tendency to go very far south recently," said Prof Sweeney.
"At the moment it is locked over Morocco and the Northern Sahara.
"As a result we are getting the colder polar air streams that we wouldn't normally expect at this time of year. That has given us the cold showery weather that is causing such problems for farmers."
In order for grass to grow farmers need soil temperatures above 6C, but over the past three months they have remained low, and March was the coldest month on record in many areas.
Climatologists are reluctant to draw conclusions about climate change from relatively short spells of weather.
However, Prof Sweeney said: "If the models for climate change are correct we can expect these kinds of aberrations to become more common.
"They will manifest themselves in cold snaps and more intense downpours of rain.
"That does not mean an end to global warming. It just means that we will have more extremes."
Prof Sweeney points to research showing that the loss of summer ice and the warming of the Arctic is playing havoc with the jet stream, and reducing its strength.
"Because the jet stream has less vigour it is wandering around like a river with less gradient, and it is getting locked in strange positions.
"We are getting air flows from unusual directions for long periods of time. This spring we have mostly had a north-westerly air flow."
All hope has not been lost for a hot summer, however.
"We could get an extremely warm summer later in the year if the jet stream is locked in the opposite position," he said.
Gerald Fleming, head of the forecast division at Met Eireann, said: "It is difficult to ascribe day-to-day weather changes to climate change.
"However, a lot of research is going on into the frequency of extreme weather events that we have seen recently.
"It is not definitive, but there is a suggestion that climate change plays a role in that."
The low temperatures have had a catastrophic effect on farmers across the country, as grass failed to grow.
Dr Michael O'Donovan of the farm research body Teagasc said: "Growth of grass in the country is between four and six weeks behind what it should be.
"Grass growth in parts of the country is 50pc down."
The Irish Farmers Association estimates that up 30,000 tonnes of fodder, mainly hay and haylage, has been imported from Britain and elsewhere.