"We have brought together 30 heads of state and government and the international community on the sidelines of the General Assembly of the UN in order to provide support and ensure that the Paris conference will be a success," Francois Hollande, president of France and president of the UN Climate Conference to be held in Paris in December, told press here Sunday.

On the lunch menu, was "landfill salad" made from vegetable scraps and rejected apples, and burgers with bruised beet ketchup and pickled cucumber scraps, to bring attention to the impact of food waste on climate change.

Hollande said that world leaders at the lunch agreed there would be an agreement reached in Paris in December but that they were unsure how ambitious it would be.

"Everybody is now convinced that there will be an agreement in Paris but the matter now is to know what agreement and with what ambitions," said Hollande.

"But we have to go further," he said, "we must ensure that there is a review mechanism every five years...to ensure that we will meet our objective at the end of the century (to) limit warming to below 2 degrees."

Ollanta Humala Tasso, president of Peru -- which hosted the previous UN Climate Conference in 2014 -- said he was optimistic about the possibility of an agreement in Paris, despite governments failing to reach agreement at previous such meetings. He said that the changed attitude to climate change negotiations was in part because the economic impact of climate change was already being felt.

"I think we have to be optimistic we can`t say why can we do it now if we haven`t in the past, that attitude is a loss of optimism," he said. "We are already feeling palpable objective economic effects which are the result of global warming and probably before the industrialized world was not aware of them did not perceive that clearly."

UN Secretary-General Ban Ki-Moon said that the lunch -- which took place on the sidelines of the UN Sustainable Development Summit -- was designed to bring attention to the connection between food and climate change.

"Our lunch was produced from food that would otherwise end up in landfills, emitting methane, a potent greenhouse gas," he said. "Food production and agriculture contribute as much to climate change as transportation."

"Yet more than a third of all food produced worldwide -- over one billion tons of edible food each year -- goes to waste," said Ban. "That is shameful when so many people suffer from hunger."

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