FORMER US President Al Gore said all Americans have "heavy hearts" in the wake of the Boston Marathon bombings.
Mr Gore thanked Minister of State for Development Joe Walsh for his sympathies as the former US President took to the stage at Dublin Castle to address the Hunger-Nutrition-Climate Justice conference.
"All Americans have heavy hearts in the wake of yesterday's tragedy," he said, adding there were strong links between Boston and Ireland.
In front of delegates from more than 60 countries, Mr Costello offered his deepest sympathies to the people of the US on the tragedy in Boston.
He said Irish people identified with people in Boston.
Mr Gore said those who have suffered are more likely to reach out to others, referring to the levels of Irish Aid going to developing countries.
He said one in a 1,000 year events were occurring more frequently now, as he highlighted flooding problems.
Mr Gore said human kind was now facing it's most "significant challenge"
with climate change.
He said the daily news casts were now like reading the Book of Revelations, with droughts and floods.