Mary Robinson, the UN special envoy on climate change, has said she is optimistic that an agreement can be reached at the global summit on climate change in Paris.

Former president of Ireland Mrs Robinson said she was very struck by the marked focus on the impacts of climate change on people and vulnerable societies in the addresses of leaders on the opening day of COP21.

Speaking to The Irish Times, she said she hoped that this people-centred focus would carry through to the negotiations.

"I have been very struck by the emphasis on it being people-centred," she said. "President Hollande used 'climate justice', President Michelle Bachelet of Chile used 'climate justice', [indicating] a concern for the most vulnerable.

“The problem is that unless those heads of State say it expressly to the delegations [from their countries], it may not carry down. We may be back to the same not-so-people-centred approach of the past.”

Mrs Robinson said her optimism was founded on a lot of preparation being done before this summit. She pointed to 180 countries having made commitments, in addition to further promises on climate finance.