The Taoiseach Leo Varadkar says Brexit is the political equivalent of climate change, and people need to realise it is a storm that is not going to pass.
Mr Varadkar says the decisions made over the next few weeks will impact Ireland for decades.
During the EU summit on Brexit, the Taoiseach took to his feet and raised a copy of Wednesday's Irish Times.
He read from the front page, telling the other 26 EU leaders part of the story of a woman whose father was killed at a customs post during The Troubles.
He said: "I just wanted to make sure that there was no sense in the room that in any way anybody in Ireland, or in the Irish Government, was any how exaggerating the real risk of a return to violence in Ireland."
Mr Varadkar also warned people that need to realise Brexit is not a storm that is going to pass.
"What Brexit is is the political equivalent of climate change - it's a permanent change", he said.
Taoiseach Leo Varadkar and British Prime Minister Theresa May hold talks in Brussels during an EU summit | Image: © European Union
EU leaders have been open to the idea that the UK could be given an extra year to negotiate a trade deal once they leave in March.
There had been hopes this week's gathering of EU leaders in Brussels - previously dubbed the "moment of truth" for Brexit - could overcome the impasse in negotiations.
But the bloc said not enough progress has been made and so shelved plans for a special summit to be held next month to sign off on a deal.
French President Emmanuel Macron told British Prime Minister Theresa May to "come back with a solution based on the necessary political compromise on the UK side" in order to achieve a deal.
Meanwhile, Mrs May faces another Brexit row with her own MPs at home.
A proposal for an option for the UK to extend its transition period out of the bloc beyond December 2020 is likely to see opposition from some quarters.
Theresa May leaves the EU summit in Brussels after addressing leaders | Image: © European Union
Mrs May said this would only be for "a matter of months" and is devised to help break the deadlock over agreeing a backstop solution for the Irish border issue.
European Commission President Jean-Claude Juncker backed the plan as a "good idea", claiming "this prolongation of the transition period probably will happen".
The EU would respond "positively" to any UK request to extend the transition period, European Council President Donald Tusk added.
However, Brexiteers have reacted with anger at suggestions the UK's stay within the EU's structures could be lengthened beyond what had previously been agreed as a 21-month period.
Northern Ireland's DUP, who Mrs May relies on to prop up her Westminster government, has claimed an extended transition period would mean the UK continues to "pay but have no say" in Brussels.
Everyone has accepted the October deadline for a withdrawal agreement will not be met, with some suggestion it might not even get done before Christmas.
That sets up two possibilities in November: a deal or no deal situation.
Either EU leaders will gather to sign off on a deal from the UK, or they will meet to plan for a no deal scenario where the UK crashes out of Europe.
Additional reporting: Sean Defoe in Brussels
