Green Party leader John Gormley said last night that climate change provided one of the compelling reasons to vote Yes in the Lisbon Treaty referendum.
In his first major speech linking climate change to the treaty, Mr Gormley disclosed that his decision - and that of a majority of his party members - to vote Yes was heavily influenced by the treaty's provision to take EU action on climate change.
The Minister for the Environment has been criticised for a political U-turn on the treaty by a minority of members of his party and by parties and groups campaigning for a No vote.
However, in a keynote speech delivered at a European Commission seminar in Dublin last night, Mr Gormley said neither he nor the Green Party had changed their fundamental position on Europe.
"The Green Party has long been pro-Europe. Across our 26-year existence we have fully engaged - albeit critically. Fundamentally, our stance on the EU has not changed. It remains one of critical engagement.
"And it is with this critical approach that I see the merits of the Lisbon Treaty in terms of the climate-change agenda."
He highlighted the important addition to the Lisbon Treaty of an explicit reference to climate change, put there at the request of the newly-formed Irish Government with Green involvement.
"Hard-wiring climate change into the treaty makes it a defining element of EU policy.
"It will give the climate-change agenda equivalent status to other EU policies such as competition or equality, which have served Irish and other European citizens so well in the past few decades."
Mr Gormley also outlined a number of other provisions of the treaty which he described as positive.
These included an approach to the depletion of fossil fuel, the charter of fundamental rights, and tackling the democratic deficit.
"But climate change loomed very large for my Green Party colleagues and me," he added.
The Greens leader also claimed that the treaty will provide Ireland with lasting energy security through the vehicle of Article 176.
