Former President Mary Robinson has warned the world needs zero carbon by 2050 before more islands and cities are devastated by flooding.
The environmental campaigner told 1,400 young people in Dublin that the challenge is getting people all over the world talking about climate.
“We all have to move,” Ms Robinson said at the One Young World conference in the Convention Centre.
“The world has to move to zero carbon and we all have to do it hopefully by 2050 or as close to that as we can because otherwise we will not be below 2 degrees Celsius.
“More small islands will go under, more communities will be flooded, big cities will be flooded and we don’t want that.”
Delegates from all over the world are in the capital for the four day event, which aims to highlight the pressing issues the world faces.
Poverty campaigner Bob Geldof, activist Ali Hewson, United Nation secretary general Kofi Annan and Mark Pollock, a blind South Pole adventurer who is now exploring a cure for paralysis, are among the key speakers.
Mrs Robinson, a member of The Elders, said she set up her charity The Mary Robinson Foundation - Climate Justice (MRFCJ) in Ireland in the northern part of the world because people in developing countries already know about the affects of climate change.
She maintained that 95pc of scientists are absolutely convinced humans affect climate most through fossil fuel and green house gas omission and warned a new assessment report out in the coming days “will shock us”.
“We are in a frightening situation, and anybody who is either a climate denier because the fossil fuel lobby has persuaded them to be, or a genuine person, they cannot take away from the scientific evidence and strong strong evidence that we are not good stewards and we have to change course,” she said.
Ms Robinson said many would like to see an international court on environmental issues, where corporations are held responsible if they affect indigenous people or landowners.
She also spoke out about energy poverty and argued for the need of clean energy for the 1.3bn people worldwide who do not have access to electricity.
“2.6 billion still cook on open fires, with charcoal and wood and animal dung and inhale the smoke,” she said.
“Four million die every year and it’s mainly women or children standing around while their mothers are cooking.”
Ms Robinson said clean energy could change everything for poor families.
“It frees up the time of women who don’t have to go miles for fire wood and destroys trees,” she added.
“Children can do homework in the evening, they can charge telephones and mobiles phones and earn an income. There are all types of ways it changes lives.”
INM is the media partner of the summit.
After winning the Budget battle over the income tax rate cut, Taoiseach Enda Kenny pressed home the advantage yesterday by confirming there will be further rate reductions in the coming years, before the general election and beyond.