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.
The south east, east Midlands,Yorkshire and Humberside, north west and Merseyside and the north east are still suffering from "high" air pollution levels, Defra has warned.
A fresh air mass arriving later today is expected to push the pollution eastwards over the North Sea.
Two sightseers have been pictured standing near the edge of crumbling chalk cliffs, seemingly unaware of the danger that could befall them.
The pair were spotted at the top of Birling Gap, near Eastbourne, East Sussex, where around three metres of cliff has fallen in recent months.
Close to where they were standing a large crack could be seen on the cliff-top - a stark sign of how precarious it is at the beauty spot - while a cottage nearby had to be demolished due to the continuing coastal erosion.
The number of people experiencing breathing problems increased by 34 per cent on Thursday, London Ambulance Service has said.
The capital experienced "very high" pollution levels yesterday but air quality is expected to improve today.
We saw a 34% increase in patients with breathing problems yesterday compared to an average Thu
People with asthma may also find that they need to use their inhaler more frequently, have it with you at all times
Daybreak's Chief Correspondent Richard Gaisford tweeted from London's Parliament Hill:
Environmental campaigners have urged politicians not to ignore the cloud of smog that has smothered parts of the UK over the last few days, saying they are "playing with people's lives".
Friends of the Earth's Jane Thomas told Daybreak, "29,000 people a year die prematurely in London alone" from pollution created by emissions.
Air pollution levels remain high across parts of England and Wales but are expected to reduce later today.
The Department for Environment, Food and Rural Affairs (Defra) reports that more than 20 areas from northern England down to the South East are still gripped by high levels of pollution this morning.
But a fresh air mass arriving later is expected to push the pollution eastwards over the North Sea, weather forecasters have said.
Higher numbers of complaints about breathing difficulties are thought to have been brought on by record pollution levels in recent days.Read the full story ›