Protesters took to the streets of New York again this evening, as world leaders prepare to fly in for a summit on climate change.
Organisers say this meeting - and next year's in Paris - will be different and insist promises made will be kept. ITV News' Science Correspondent Alok Jha reports:
Greenpeace UK has said world leaders should aim for more than "just another sticking-plaster deal" on climate change.
Executive director John Sauven said: "Never has a generation of world leaders stood a better chance of clinching a global climate deal.
"This time there's enough momentum to aim for something better than just another sticking-plaster deal with a short shelf life.
"David Cameron now has the opportunity to argue for a similar system that can drive a global countdown towards zero emissions - he should seize it with both hands."
A coalition of environmental groups and charities have set out what they want to see from a global climate deal.
The group, including Greenpeace, WWF, the RSPB and Christian Aid, said an international agreement should include ambitious plans by countries for taking action both before and after 2020.
It should also provide a clear legal framework for delivering and monitoring greenhouse gas emissions cuts.
An agreement, which backers want to see signed at the end of 2015, establish a framework with rolling commitments to reduce emissions and support efforts to adapt to a changing climate, they added.
David Cameron should push other leaders to follow the UK's lead in setting a series of targets to drive down climate emissions, environmental groups have urged.
A new international climate deal, which backers want to see signed at the end of 2015, should follow the example of the UK's Climate Change Act, which includes a series of five-year "carbon budgets" for reducing greenhouse gases over time, they said.
They stressed that the Prime Minister should use the momentum building ahead of a climate summit in New York later this month to push for a strong international deal in 2015.
Short, sharp downpours could become an increasingly unwanted characteristic of the British summer if the effects of global warming are to continue, experts have warned.
A landmark study by the Met Office and Newcastle University has identified how climate change could result in heavier summer rainfall, which in turn could increase the risk of flash flooding.
The White House has called for urgent action to mitigate the affects of climate change, in its third National Climate Assessment.
It its starkest warning to date, the Obama administration said the effects of climate change are already being felt, and already costing money. The report said:
"Climate change, once considered an issue for a distant future, has moved firmly into the present."
The report has be called a "game changer" as it details, for the first time, the predicted effects on different regions: Residents in the northeast coast could face bigger storm surges and flooding, whilst the southwest of the country is likely to confront more wildfires and severe water shortages.
The world has to move quickly "if it's serious about limiting temperature increase, Dr Rajendra Pachauri, of the Intergovernmental Panel on Climate Change told ITV News today.
Energy Secretary Ed Davey told ITV New correspondent Lewis Vaughan Jones that the report shows a very real threat, but denied that Government hasn't done enough to move towards more sustainable energy.
Today's UN report on climate change is a "stark warning" about the need to reduce carbon emissions, Energy Secretary Ed Davey has told Sky News' Murnaghan programme.
The Liberal Democrat MP also said the decreasing cost of renewable energy meant decarbonising need not be overly expensive.
I agree we should be doing absolutely everything. This is a stark warning that the world is looking down the precipice if we don’t take action now. But it also says - and some good news - is that the cost of renewables, things like solar and wind, are coming down, so we can go green in an affordable way.
Massive cuts to global greenhouse gas emissions needed in the next few decades to avoid "dangerous" climate change, a major international report has warned.
It is still possible to keep global temperature rises to no more than 2C above pre-industrial levels by the end of the century, the level at which it is thought dangerous impacts of climate change will be felt.
But substantial reductions in greenhouse gases will be needed, through large-scale changes to energy supplies and use, as well as curbing deforestation and planting forests.
Emissions need to be reduced by 40% to 70% on 2010 levels by the middle of the century and to near zero by 2100, to make it likely temperatures will not go above 2C, the report said.
Environmental campaigners have reacted to leaked drafts of the latest UN report into climate change, saying they showed "catastrophic" climate change could only be avoided by reducing dependency on fossil fuels.
Friends of the Earth's executive director Andy Atkins said we are already on track for four degrees warming "which will be impossible for human society to adapt to".
We have the technology to prevent dangerous climate change. What we lack is the political will of our leaders to strongly champion renewable power and energy efficiency.
Tim Ratcliffe from campaign group 350.org said that 80% of fossil fuels need to stay underground in order to avoid a climate catastrophe.