The widow of Nelson Mandela punctured the self-congratulatory mood of the UN summit on Tuesday, saying world leaders had failed to rise to the challenge of climate change.

“There is a huge mismatch between the magnitude of the challenge and the response we heard here today,” Graça Machel told the closing moments of the summit. “The scale is much more than we have achieved.”

The gathering of 120 world leaders – the first such meeting on climate change in five years – resulted in a day of impassioned speeches, including a cameo from the actor and UN ambassador Leonardo DiCaprio.

Climate March

Several of the speeches, including that of Barack Obama, mentioned the 300,000 people who turned out for Sunday’s climate march. “Our citizens keep marching. We cannot pretend we do not hear them,” the president said.

But, as anticipated, the leaders held back on making new commitments to cut greenhouse gas emissions or to give significant climate finance to developing countries, leaving it to business, cities and campaign groups to produce the real action on climate.

The searing critique of the summit carried additional weight because Machel is one of the Elders, global leaders charged with working for peace and human rights.

She spoke only moments after the UN secretary-general, Ban Ki-moon, had declared the gathering a success. “We have delivered,” he said.

But Machel said leaders had failed to offer an adequate response to the hundreds of thousands of people who came out in the streets this week to demand action on climate change – and the millions in poor countries who will suffer its effects.

“Can we genuinely say we are going to preserve their lives, and ensure their children and grandchildren and great-grandchildren inherit a planet which is safe and sustainable?” she asked.

Machel appealed to world leaders and business executives who descended on the UN on Tuesday to “go back to the drawing board”. She concluded: “The obligation in my view is to step up the ambition.”

Campaign groups also criticised the result.

But Al Gore, the climate champion and former US vice-president, said the summit – the first such meeting on climate in five years – was still a net positive. “There is no question that a considerable amount of momentum was generated here,” Gore told the Guardian. “I think it was a tremendous boost to the whole movement that is towards the Paris agreement.”

China’s emissions

Barack Obama, in the most rousing speech of the day, said the US had done more under his presidency to cut carbon pollution than any other country, and volunteered to help lead the international community to an international agreement to fight climate change at a meeting in Paris at the end of next year.

“There should be no question that the United States is stepping up to the plate,” he told the summit, saying the US recognised its role in causing climate change.

China, which has surpassed the US as the world’s biggest emitter, said it would also do its bit, by curbing emissions “as soon as possible”.

Zhang Gaoli, the vice-premier, said China was on track to reduce carbon intensity by 40% from 2005 levels by 2020. “As a responsible major developing country, China will make an even greater effort to address climate change and take on international responsibilities that are commensurate with our national conditions.”

The UK prime minister, David Cameron, also touted his government’s environmental policies. “As prime minister I pledged to lead the greenest government ever and I believe we have kept that promise,” he said.

And France, which as host country will oversee the final stages of negotiations on a global deal, held out the prospect that dealing with climate change would also bring a new international economic order. “What will come out of Paris is a new economy,” the president, François Hollande, told an investors’ event on the sidelines of the summit.

Hollande took a swipe at world leaders who had been voicing their concerns about climate change for decades – without taking decisive actions to cut emissions, or aid poor countries which will bear the brunt of climate change.
“We can’t just limit ourselves to words, expressions of regret and exercises in stock-taking,” he told reporters.

France went on to commit to providing $1bn to a climate change fund for poor countries – the first significant contribution since Germany threw in $1bn last July. Sweden has also contributed.

Green Climate Fund

The Green Climate Fund was founded in 2010 to help poor countries cope with climate change. UN officials and developing country diplomats have said repeatedly it will not be possible to reach a climate deal in Paris, without a significant fund for those countries which did the least to cause climate change but will bear the brunt.

South Korea and Switzerland went on to pledge $100m each, Denmark pledged $70m, Norway pledged $33m and Mexico said it would give $10m.

But the total of $2.3bn pledged for the Green Climate Fund so far fell short of the $10bn to $15bn that UN officials and developing country said was needed to show rich countries were committed to acting on climate change. It also was unclear whether Tuesday’s pledges represented new money.

“We welcome new pledges of money from France and others, but they fall well short of what’s needed. With poor communities around the world already losing their homes and income due to climate change, all rich countries must pledge to the Green Climate Fund and set a clear timeline of when the money will be available,” the campaign group ActionAid said in a statement.

The summit did produce other initiatives in addition to the climate cash, but these too were relatively modest, and all relied on partnerships with business and NGOs.

Carbon pricing

In the headline event at Tuesday’s summit, more than 400 companies from 60 countries all signed on to support putting a price on carbon.

Some of the world’s biggest palm oil and paper producers committed to stop destructive logging by 2030, and restore an area of forest equivalent to the size of India.

Nigel Purvis, the chief executive of the Climate Advisers consultancy which worked to get the deal, said: “This is like if Exxon Mobil and the Koch brothers got together to cut greenhouse gas emissions.”

But Brazil, despite its critical role protecting the Amazon rainforest, said it had been left out of the negotiations. A number of campaign groups did not sign the agreement, saying it did not go far enough to protect the rights of indigenous people who rely on the forest, or to hold the big forestry companies to account.

“I think that it’s impossible to think that you can have a global forest initiative without Brazil on board. It doesn’t make sense,” Izabella Texeira, the Brazilian environment minister, told the Associated Press.

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