A stream of national pledges have put the planet closer to tackling climate change but there is more work to do, experts said Monday, as leaders pressed for a strong new UN accord.

A week of climate events in New York ahead of the annual United Nations summit brought out new promises from governments and the private sector to slash greenhouse gas emissions blamed for Earth's rising temperatures and severe weather.

The United Nations offers one of the last opportunities for high-level talks before the conference opens on November 30 in Paris with the aim of sealing a far-reaching new global climate agreement.

French President Francois Hollande has sought to rally nations to come up with both emission cut plans and financing for the worst-hit poor countries.

"I tell you here, and I tell you plainly -- if it is not (a deal) in Paris, it will be too late. It will be too late for the world," Hollande said in an address to the UN General Assembly.

- China brightens projections -

A UN summit in Copenhagen in 2009 set a goal of keeping temperature rises at no more than two degrees Celsius (3.6 Fahrenheit) 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 have put the planet one degree Celsius closer to that target.

The Earth is now on track for temperatures to rise 3.5 degrees (6.3 Fahrenheit) above pre-industrial levels, with a range of uncertainty between 2.1 and 4.6 Celsius, said the analysis, produced with the Massachusetts Institute of Technology.

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 two-degree 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," Jones told AFP.

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

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.

- Eyes on India -

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

India will unveil its strategy on Thursday, Environment Minister Prakash Javadekar told a climate event in New York.

Indian Prime Minister Narendra Modi, meeting US President Barack Obama in New York, called for a "comprehensive and concrete" agreement in Paris.

"This is an exercise we are undertaking in the spirit of our culture and tradition, but also because of our commitment to the future of this planet," Modi said.

But Jones doubted that the Indian plan would change calculations as New Delhi was expected to announce a reduction in carbon intensity in line with action the country was already on course to take.

- Local action -

Obama has pushed for a strong climate agreement but faces robust opposition from the rival Republican Party, which is friendly to the fossil fuel industry.

Still, local governments -- led by California, the largest US state -- and businesses have taken a lead in tackling climate change.

The Climate Group, which organizes the New York events, said in a report Monday that 172 major companies, states, regions or cities worldwide have pledged either to reduce greenhouse gas emissions by 80 to 100 percent or to switch entirely to renewable energy.