The former president of Ireland Mary Robinson has called on developed nations to cut their consumption levels.
Mrs Robinson, 72, negotiated with world leaders ahead of the Paris Agreement on climate change, arguing strongly for "climate justice", and speaking at the One Young World Summit in Ottawa, Canada, she once again stressed the need for change.
"We don't need to consume as much as we have in the world," she said.
"We have a world where there's inequity and inequality. We can be simpler in the parts of the world that have benefited from fossil fuel."
Mrs Robinson used the number of toys her grandchildren have as an example of over-consumption, adding: "We have to change, we cannot go on with business as usual.
"We need each of us to think about our carbon footprint. Eat less meat, or no meat at all. Become vegetarian or vegan.
"Let's commit to the Paris agreement. Let's commit to leave no one behind."
T he former United Nations High Commissioner for Human Rights was speaking at the summit, which brings 1,300 current and future young leaders from 196 nations together in order to discuss issues ranging from peace and security to business and education.
Mrs Robinson's call for people to reduce their carbon footprint by eating less meat or none at all is "facile sensationalism", the president of the Irish Creamery Milk Suppliers Association (ICMSA) has said.
Deciding whether it's "necessary or desirable to fly around the world from seminar to seminar urging others to give up meat and dairy for the planet's sake", should be the former Irish president's concern, John Comer said.
"It's just a fact, for instance, that milk production places less stress on the environment in Ireland, by virtue of our grass-base, than almost anywhere else in Europe or the world. That wouldn't be true of other staples and we might see the merit in specialising according to environmental suitability."
He added: "Mrs Robinson is of course entitled to her views but we'd expect them to take reality as their starting point. This is the greatest challenge facing mankind and there's no room for this kind of facile sensationalism we saw from Mrs Robinson in Ottawa."
Mrs Robinson spoke again at the One Young World Summit in Ottawa, Canada, stressing the issue of "climate justice" her foundation focuses on.
" It's the poorest countries and poorest communities... that are suffering disproportionately from climate change," she said, using the affects of El Nino in Ethiopia as an example.
"What we need is some kind of a body for future generations. A guardian body that would keep reminding, we're not actually doing enough.
"We do need to create more spaces for young people to have their voices heard. This is such an intergenerational issue. We have to move away from business as usual, and we're not enough.
"We must ensure that there is a transfer of technology and financing to developing countries, so that they don't go the route of coal and oil and gas."
Closing, Mrs Robinson quoted Archbishop Desmond Tutu: "We have to be prisoners of hope."
Mrs Robinson was praised for creating a space for women to talk about climate change, and awarded the first Mary Robinson climate prize to Barkha Mossae, a Mauritian diplomat and One Young World ambassador.