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.
Campaigners have demanded the world moves away from using fossil fuels, ahead of a major international report by the UN's Intergovernmental Panel on Climate Change.
The latest report will set out ways to curb rising temperatures by tackling greenhouse gas emissions.
The third of a trilogy, the study comes just two weeks after the second part of the report warned that the effects of rising temperatures were already being felt across the world.
It said that without action climate change would increasingly threaten security, health and food supplies, exacerbate poverty and damage species and habitats.
Responding to the IPCC's influential report on the impact of climate change, Foreign Secretary William Hague said that "Governments everywhere have to act."
It is clear from the IPCC's report that a two-degree increase in the world's temperature would be dangerous, and four degrees would be catastrophic.
But that is the likely trajectory, unless there is unprecedented global co-operation to bring down emissions.
No country would be left unaffected. Governments everywhere have to act.