Ireland is getting warmer and wetter, with swallows arriving earlier and frosts later, in trends that mirror global climate change, according to a scientific study published yesterday by the Environmental Protection Agency.
The study, Climate Change: Indicators for Ireland, said these changes in the weather could be attributed substantially to the build-up of greenhouse gases in the atmosphere, mainly as a result of burning fossil fuels such as coal and oil.
However, it may also be due to the "natural oscillations" of the Atlantic weather system, according to the study, which recommends that an integrated monitoring strategy should be implemented as a matter of urgency to gather more data.
Dr John Sweeney, of the geography department at NUI Maynooth, said the north-west was experiencing wetter winters while the south-east was comparatively drier because there was now "more variation in rainfall nationally" than in the past.
Dr Sweeney, one of the authors of the EPA-commissioned study, cited the example of Valentia Island, where the first and last frosts of winter were now occurring slightly later. Cork and Kerry had only half the frosts of a decade ago.
There has been a significant decrease in the frequency of cold days nationally and a general increase in warm days, due mainly to a rise in temperature at night in winter, with an overall increase in average temperatures throughout the 20th century.
An average increase in annual temperature of 0.5 degrees Celsius has been observed since 1900, with the most significant warming taking place in the past decade - though Dr Sweeney said the 1940s were warmer than the global average.
Climate change impacts are projected to increase in future years and may result in major environmental changes as well as economic and social problems, such as the serious flooding that hit parts of Dublin when the Tolka burst its banks 10 days ago.
There is also a convergence between meteorological trends and trends in natural wildlife phenomena. For example, swallows arrive two days earlier for every 1 degree rise in the March temperature; this has also advanced tree growth by one week.
Several migrant bird species have appeared in Ireland during the past five years as a result of our warmer weather. These include the Little Egret, Reed Warbler, Pied Flycatcher, Bearded Tit, Mediterranean gull, goosander, lesser whitethroat and blackcap.
Native Irish bats appear more active in winter than their counterparts in southern England, though this may have been the case for some time, according to the study. The length of the growing season has increased significantly since the late 1970s.
Warm weather crops are also more widely grown, with a rapid increase throughout the 1990s in the acreage of forage maize. But potato yields have been adversely affected by drier weather in late summer in areas without irrigation.
The study was carried out by scientists at NUI Maynooth and Trinity College Dublin. Copies are available for €7 from the Environmental Protection Agency, Richview, Clonskeagh Road, Dublin 14. Phone 01-2680100, Fax 01 2680199.