SCIENCE HAS SPOKEN

The ICCP Synthesis Report has been published in Copenhagen, as the Secretary-General of the United Nations said: 'Science has spoken. There is no ambiguity in their message. Leaders must act. Time is not on our side':
http://www.bbc.co.uk/news/science-environment-29855884

The Synthesis Report says the unrestricted use of fossil fuels should be phased out by 2100, if the world is to avoid dangerous climate change. Most of the world's electricity can, and must, be produced from low-carbon sources by 2050. 

If not, the world faces severe, pervasive and irreversible damage. Inaction would cost much more than taking the necessary action.

The Report states:

Warming is unequivocal and the human influence on climate is clear;
Since the 1950's the observed changes are unprecedented over decades to millennia;
The period from 1983 to 2012 was likely the warmest 30 year period of the last 1,400 years;
Warming impacts are already being seen around the globe, in the acidification of the oceans, the melting of arctic ice and poorer crop yields in may parts;
Without concerted action on carbon, temperatures will increase over the coming decades and could be almost 5 C above pre-industrial levels by the end of this century. 

Reducing emissions is crucial if global warming is to be limited to 2 C, the threshold of dangerous climate change.

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, fossil fuel power generation without carbon capture and storage (CCS) technology must be phased out almost entirely by 2100.

CCS is proving slow to develop. So far the world has only one commercially-operating plant of that type, in Canada, and progress making the technology widespread and affordable is far slower than many had hoped.

Comment: The message from science is clear. Now the 2015 Paris summit meeting must deliver a new global treaty on climate.