Climate change is the most pressing problem facing Europe today and must be tackled urgently, according to Pat Rabbitte.
The Labour leader was addressing the national forum on Europe in Dublin Castle today.
Mr Rabbitte said a modest investment in curtailing emissions now will prevent runaway climate change, the dire consequences of which "we can only imagine".
He said: "While the economic and environmental challenges are demanding, but achievable, the scale of the diplomatic challenge is enormous. I can think of no precedent in history for the level of co-operation and trust that will be required among all the major world powers if this problem is to be tackled."
Delaying taking action on climate change will be costly and dangerous, according to Mr Rabbitte.
"What is required is a coming together, at a minimum of the US, Europe, Russia, India, China, Japan, and Brazil, where everyone has an incentive to let the others carry the burden of carbon reduction, and yet, without co-operation from all, the broader goal cannot be met," he said.
He called for Europe to take the lead in forging an international political consensus on the action needed to tackle the problem.
Mr Rabbitte also spoke of the importance of the European Union meeting commitments made in 2005 to reach the UN target of 0.7 per cent of national income in overseas aid.
He also called for EU action to stop human trafficking across Europe.
"A new form of slavery now exists, whereby women and children are held captive for the purposes of sexual exploitation, and are trafficked across Europe for that end. It is a manifestly European problem that manifestly requires a European solution," he said.
"Europe needs to do more to seal its borders, and to chock off this abhorrent trade," he said.
Mr Rabbitte said his party supported the draft Constitutional Treaty, saying it had been a significant achievement for the Irish presidency.
The failure of the referenda in France and The Netherlands to ratify the treaty was due to what he called the failure of Europe's elites to persuade the public of its necessity.