Major changes to residential planning, agriculture and infrastructure are required to prepare Ireland for climate change due to global warming, the Environmental Protection Agency (EPA) has warned.
The warning comes on foot of a report by the agency which predicts increased flooding in the winter and drought in the summer within 60 years because of global warming.
The report on climate change, written by 17 climate and environment experts, predicts "dramatic changes" in rainfall patterns.
Within 50 years, Ireland will enjoy milder winters, with temperatures an average 1.5 degrees warmer by the end of the century.
Winters will also experience increased rainfall of up to 10 per cent, with the north-west experiencing the biggest rainfall increases.
Average summer temperatures will increase by nearly 4 degrees within 70 years, according to the report. The authors predict this rise will see midland areas experiencing typical summer daytime temperatures of up to 24.5 degrees.
However, rainfall in the south and east will drop by up to 40 per cent, which could result in widespread water shortages.
Dr Mary Kelly, director general of the EPA, warned that extreme weather events were now more common in Ireland and Europe, such as recent flooding in Galway and the heatwave on the continent.
"Climate change is happening, and it's happening at a rate we can see."
She said reductions in greenhouse gas emissions would only have an impact in the long-term, and warned that the country would have to prepare for changes.
"Without seriously incorporating climate change impact assessment into policy, Ireland runs the risk of failing to position itself to deal with the major challenges ahead."
Many aspects of national policy would need to be "climate change-proofed", said Dr Kelly.
"Climate change considerations have not historically been central in the formulation and development of policy in Ireland.
"However, the impact scenarios described in the research we are publishing today imply that this needs to change."
She said planning policy was one area which needed to see significant change because of an increased risk of flooding and sea level rises.
Dr John Sweeney, of the department of geography at NUI Maynooth, the chief author of the report, said water resources in the south-east would come under severe pressure during summer because of rainfall decrease. "Competition for scarce water resources will become more common."
This will also have an effect on agriculture, with the potato becoming less viable in the south-east, while soya beans and maize could be grown more easily.
Crop yields of grass, the largest crop in Ireland and main animal feed, could also suffer from lower summer rainfall.
He said some animals, especially those adapted to Arctic conditions, would become extinct in Ireland, although species associated with warmer climates will become more common.
Dr Sweeney believes the biggest impact, however, will be in relation to flooding, with sea level rises combined with more extreme weather events making flooding more likely.
"Increased hazard is the area we should be looking at. It's how weather extremes will change . . . and what effect they will have."
Research by Dr Sweeney also suggests that the most heavily populated areas are those most at risk from flooding.
Sea level rises of up to a metre over the next century will see 300 square kilometres of land under threat. Coastal areas in Dublin city, the east coast along counties Meath and Wicklow, and Cork Harbour have all been identified as being particularly vulnerable.