NEW YORK – Reaching a successful climate deal in Paris at the end of the year is the last chance to save the planet, France’s president Francois Hollande has warned.

Without “this decision in Paris t will be too late for the world,” Hollande said in his address to the UN General Assembly in New York.

The UN-led conference in Paris, which starts at the end

of November, aims to seal a wide-ranging agreement to limit the worst effects of climate change.

Despite the warning, Mr Hollande sounded a note of optimism after China and the United States signed a “joint vision” ahead of the Paris summit, and China committed to a domestic cap-and-trade carbon exchange.

“We have moved forward over recent months,” Hollande said.

“Very strong declarations were made by those countries who are most responsible for global warming – the United States and China, which undertook commitments towards changing the situation.”

He also pledged that France would increase its financial commitment on climate from three billion to five billion euros (US$4.8 billion to $8 billion) between now and 2020.

A week of climate events in New York ahead of the annual UN summit brought out new promises from governments and the private sector to slash greenhouse gas emissions blamed for global warming.

The United Nations offers one of the last opportunities for high-level talks before the Paris conference opens on November 30.

A UN summit in Copenhagen in 2009 set a goal of keeping temperature rises at no more than 2 degrees Celsius from pre-industrial times, a level that is still expected to cause growing droughts and disasters but which scientists consider comparatively manageable.

Climate Interactive, a Washington-based group whose analysis is used by leading governments, said that pre-Paris plans had put the planet 1°C closer to that target.

The Earth is now on track for temperatures to rise 3.5°C above pre-industrial levels, with a range of uncertainty between 2.1°C and 4.6°C, said the analysis, produced with the Massachusetts Institute of Technology (MIT).

The group had earlier projected a temperature rise of 4.5 degrees Celsius.

But an increase of “3.5 degrees is absolutely too much and is not a world we want to be adapted to. It is actually a world we cannot adapt to,” said Andrew Jones, co-director of Climate Interactive.

However, he said that the world could still meet the 2°C goal if rich nations go ahead with plans to peak carbon emissions by 2020 and developing countries do so a decade later.

“We believe that a good chance at two degrees is still possible,” said Jones.

Some low-lying island states had pushed for a more ambitious goal of 1.5°C as rising sea levels put at risk their very survival.

Kiribati, with its population of 110,000 spread across 33 low-lying islands, is particularly vulnerable to climate change and has called on Australia to take more action.

Jones said that a “huge” factor in the new analysis was China, the world’s largest carbon polluter, which in June pledged that its emissions would peak by 2030.

Other key actors include Mexico and Brazil, which in contrast to many emerging economies have promised absolute cuts in carbon emissions, not just a slowdown.

With an announcement at the United Nations on Sunday by Brazil, India is the only major country that has not submitted a climate plan but is expected to do so on Thursday.