Impact of big freeze: ‘Grass growth will be delayed by two weeks’

As farmers continue to grapple with exceptionally high levels of snowfall nationwide, concerns have now emerged about the impact of the big freeze on grass growth this spring.

John Sweeney, professor (emeritus) of geography at Maynooth University, has warned that grass growth will be delayed by at least two weeks in the aftermath of Storm Emma and the so-called ‘Beast from the East’.

The leading climatologist has also warned that such problems will be exasperated if farmers run out of fodder in the next two to three weeks.

All we can say for farmers is that grass growth will be delayed – there will be problems.

“St. Patrick’s Day is usually when people start planting their spuds and March 1 is often when some cattle go out into the fields; but, I think they are now looking at a couple of weeks delay.

“It has been a miserable time for farmers; especially with the wet autumn. The first half of January wasn’t particularly dry by comparison to last winter; so I don’t think things are very far advanced at this stage.

“It will certainly be a couple of weeks behind schedule,” he told AgriLand.

Although the current weather system is being described by some as an “exceptional event”; many scientists are concerned that the situation is a precursor to more extreme and less predictable weather.

But is the severe snowfall linked to climate change? According to Sweeney, the two may be linked.

Climate change link

“We can’t say an individual event like this is necessarily caused by climate change; we’ve had these kinds of events all through history. In fact, I noticed that we had a very similar event written about in 1028 in the annals of Innisfallen.

“But what we can say is this is an exceptional extreme and it’s the kind of extreme that we could expect to see more often,” he said.

He pointed out that lot of research at the moment suggests the oscillations in the jet stream (movement back and forth) that are behind these kinds of extreme events are becoming more frequent as a result of melting sea ice in the northern latitudes.

Last Sunday we had a temperature in the north pole of +2º degrees centigrade, which is about 20º or 30º warmer than normal.

“We also had snow in the Sahara last month; so we’re getting signs of extremes becoming more frequent. And that is the kind of extreme that we would expect to get as the jet stream is wobbling more,” he said.

However, he stressed that scientists would need to be able to look at the frequencies in greater detail over a longer period to definitively establish that climate change is behind such systems.

“This kind of an event on its own is not caused by climate change; but, it’s the kind of extreme event that we would expect to see occurring if current speculation about the nature of northern hemisphere climate change is ultimately correct.

“We have seen in Ireland the wettest winter on record; the stormiest winter on record in the past three or four years. We saw some extreme events this summer in Europe, and earlier this year in North America, so there is a tendency to expect more extremes,” he said.

Quick thaw warning

However, Prof. Sweeney – a former president of An Taisce, the national trust for Ireland – admits that he is “a bit surprised” that the country is in the midst of such an intense event so soon after last October’s Hurricane Ophelia.

“What’s unusual is the joint probability of the blocking anti-cyclone over Scandinavia, and the easterly winds from Siberia, occurring at the same time as a relatively moisture laden warm depression coming up from Portugal. It was that combination of events that made this very unusual.

“I’m a bit surprised; I wasn’t expecting that kind of extreme event in terms of coldness and snowiness. But the track of Storm Emma was not too dissimilar to the track of Hurricane Ophelia,” he said.

Although Prof. Sweeney says the worst of the storm’s blizzard conditions are over; he anticipates that a lot snow will fall over the next six to eight hours.

“From tomorrow on I would expect more rain and sleet to develop and hopefully a slow thaw,” he said.

The last thing we want is a quick thaw in this situation. It will be over and done with by the middle of next week.