This article is from the source 'bbc' and was first published or seen on . It last changed over 40 days ago and won't be checked again for changes.

You can find the current article at its original source at http://www.bbc.co.uk/news/science-environment-29855884

The article has changed 5 times. There is an RSS feed of changes available.

Version 1 Version 2
Fossil fuels should be 'phased out by 2100' says IPCC Fossil fuels should be 'phased out by 2100' says IPCC
(about 1 hour later)
The unrestricted use of fossil fuels must end soon if the world is to avoid dangerous climate change. The unrestricted use of fossil fuels should be phased out by 2100, if the world is to avoid dangerous climate change, a UN-backed expert panel says.
That is the central message of a stark new report from the UN-backed Intergovernmental Panel on Climate Change. The Intergovernmental Panel on Climate Change says in a stark report that most of the world's electricity can - and must - be produced from low-carbon sources by 2050.
The IPCC urges that by 2050, most of the world's electricity must - and can - be produced from low carbon sources. If not, the world faces "severe, pervasive and irreversible" damage.
Fossil fuels, without carbon capture and storage (CCS), should be phased out "almost entirely" by 2100. The UN said inaction would cost "much more" than taking the necessary action.
The short Synthesis Report was published on Sunday in Copenhagen, after a week of intense debate between scientists and government officials. "Science has spoken," Secretary-General Ban Ki-moon said. "There is no ambiguity in their message. Leaders must act. Time is not on our side."
The report says the world faces "severe, pervasive and irreversible" impacts without effective action on carbon. The IPCC's Synthesis Report was published on Sunday in Copenhagen, after a week of intense debate between scientists and government officials.
"It's very clear from the report that fossil fuels have had their day," said Prof Arthur Petersen from UCL and a member of the Dutch government's team in Copenhagen. "There is a myth that climate action will cost heavily," said Mr Ban, "but inaction will cost much more."
"Of course it is up to politicians to decide which risks they want to take with climate change, so it is not policy prescriptive in saying that these reductions should take place, but it is absolutely clear that the reductions should take place if you want to limit (temperature increases) to 2C." "We have to first lower the temperature as you will to do with your children, that is what we are doing, that requires some massive, urgent and immediate action."
The US Secretary of State, John Kerry, described the report as "another canary in the coal mine".
"Those who choose to ignore or dispute the science so clearly laid out in this report do so at great risk for all of us and for our kids and grandkids," Mr Kerry said in a statement.
Rapid phase outRapid phase out
The report says that reducing emissions is crucial if global warming is to be limited to 2C - a target acknowledged in 2009 as the threshold of dangerous climate change.
For electricity production, this would mean a rapid move away from coal and into renewables and other low carbon forms, including nuclear.For electricity production, this would mean a rapid move away from coal and into renewables and other low carbon forms, including nuclear.
The report suggests renewables will have to grow from their current 30% share to 80% of the power sector by 2050.The report suggests renewables will have to grow from their current 30% share to 80% of the power sector by 2050.
In the longer term the report states "fossil fuel power generation without CCS is phased out almost entirely by 2100".In the longer term the report states "fossil fuel power generation without CCS is phased out almost entirely by 2100".
The chair of the IPCC Dr Rajendra Pachauri said that greener electricity is key. CCS refers to "carbon capture and storage" technology, which could help limit emissions but is proving slow to develop.
"If the world wants to go on this pathway of keeping temperatures increases below 2 degrees C by the end of the century, then by the middle of the century we will have to treble or quadruple the use of low carbon or zero carbon energy from renewables, and sources like bioenergy, nuclear and carbon capture and storage."
Three previous reports from the IPCC, issued over the past 13 months, have outlined the causes, the impacts and the potential solutions to climate change.Three previous reports from the IPCC, issued over the past 13 months, have outlined the causes, the impacts and the potential solutions to climate change.
The Synthesis boils these three into one, with the intention of informing politicians engaged in attempts to deliver a new global treaty on climate by the end of 2015.The Synthesis boils these three into one, with the intention of informing politicians engaged in attempts to deliver a new global treaty on climate by the end of 2015.
It re-states many familiar positions:It re-states many familiar positions:
Politicians have agreed that a rise of 2C is the threshold of danger. In this report the IPCC authors outline a number of routes to keep to that level by the end of the century.
Countries will need to adapt rapidly, but almost all scenarios see near zero emissions by 2100.Countries will need to adapt rapidly, but almost all scenarios see near zero emissions by 2100.
Analysis: David Shukman, BBC science editor
The language in the UN's climate reports has been steadily ratcheted up over the years, but this publication lays out the options more bluntly than before.
The conclusion that fossil fuels cannot continue to be burned in the usual way - and must be phased out by the end of the century - presents governments with an unusually stark choice.
The head of the IPCC, Dr Rajendra Pachauri, has tried to make it more palatable by saying that fossil fuel use can continue if the carbon emissions are captured and stored: so-called CCS. But so far the world only has one commercially-operating plant of that type, in Canada, and progress is far slower than many had hoped to making the technology either widespread or affordable.
So this raises the difficult question of how key governments are likely to respond.
The last big climate gathering - in New York in September - saw leader after leader talk up the need for action on global warming. But events in Copenhagen back in 2009, when a disastrous and dysfunctional summit failed to agree anything substantial, showed how easily rhetoric crumbles in the face of economic pressures or domestic realities.
The talk today is that attitudes have somehow changed, that next year's summit in Paris really does have a chance to reach a global agreement. Let's see.
"We can't afford to burn all the fossil fuels we have without dealing with the waste product which is CO2 and without dumping it in the atmosphere," said Prof Myles Allen from Oxford University, and a member of the IPCC core writing team."We can't afford to burn all the fossil fuels we have without dealing with the waste product which is CO2 and without dumping it in the atmosphere," said Prof Myles Allen from Oxford University, and a member of the IPCC core writing team.
"If we can't develop carbon capture we will have to stop using fossil fuels if we want to stop dangerous climate change, that is a very clear message that comes out of the IPCC reports.""If we can't develop carbon capture we will have to stop using fossil fuels if we want to stop dangerous climate change, that is a very clear message that comes out of the IPCC reports."
The clarity of the language over the future of coal, oil, and gas was welcomed by campaigners.The clarity of the language over the future of coal, oil, and gas was welcomed by campaigners.
"What they have said is that we must get to zero emissions, and that's new," said Samantha Smith from WWF. "What they have said is that we must get to zero emissions, and that's new," said Samantha Smith from World Wildlife Fund.
"The second thing is they said that it is affordable, it is not going to cripple economies.""The second thing is they said that it is affordable, it is not going to cripple economies."
Saudi concernsSaudi concerns
In their discussions on fossil fuels, there was a fierce battle over a chart that showed how much the electricity sector needed to curb its carbon. In the IPCC's discussions on fossil fuels, there was a fierce battle over a chart that showed how much the electricity sector needed to curb its carbon.
According to one observer, "the Saudis went ballistic" over its inclusion.According to one observer, "the Saudis went ballistic" over its inclusion.
Another significant fight was over the inclusion of text about Article 2 of the UN Framework Convention on Climate Change.Another significant fight was over the inclusion of text about Article 2 of the UN Framework Convention on Climate Change.
It quickly became a standoff between those who want the focus to be on cutting emissions against those who think the right to develop economies must come first.It quickly became a standoff between those who want the focus to be on cutting emissions against those who think the right to develop economies must come first.
An unlikely alliance between Bolivia and Saudi Arabia ultimately saw the section dropped entirely from the underlying report.An unlikely alliance between Bolivia and Saudi Arabia ultimately saw the section dropped entirely from the underlying report.
"There was a box in the draft, and in the end that box wasn't included in the underlying report," said Prof Petersen."There was a box in the draft, and in the end that box wasn't included in the underlying report," said Prof Petersen.
"History will tell us whether it was wise or not, there are lessons to be learned here.""History will tell us whether it was wise or not, there are lessons to be learned here."
Some of those attending said they believed that that tackling climate change and sustainable development went hand in hand.Some of those attending said they believed that that tackling climate change and sustainable development went hand in hand.
"Different countries come to different perspectives" said Prof Jim Skea from Imperial College and a review editor of the report."Different countries come to different perspectives" said Prof Jim Skea from Imperial College and a review editor of the report.
"But from the science perspective, we need them both. We need to walk and chew gum at the same time.""But from the science perspective, we need them both. We need to walk and chew gum at the same time."
Follow Matt on Twitter @mattmcgrathbbc.Follow Matt on Twitter @mattmcgrathbbc.