The UN Climate Action Summit is underway in New York, and will be attended by Leo Varadkar and other world leaders.
Ahead of his address, the Taoiseach announced that Ireland would be phasing out oil exploration off its coasts.
However, environmental journalist John Gibbons says he is essentially "agreeing to give up something that was never done", and that if the Taoiseach were serious about climate change, he would have announced a ban on fossil fuel exploration.
John also adds that Leo Varadkar "had a wonderful opportunity to engage with around 20,000 young people on the streets of Dublin when the biggest climate march in history was taking place", but instead attended the opening of a runway extension at Knock Airport.
He says the Taoiseach was "not prepared to show solidarity politically" on the issue of climate change.
Listen to the interview in full by pressing the play button on this page.