The world will have to
completely phase out fossil fuels in electricity generation by the end of this
century and reduce their use to 20% by 2050 if disastrous consequences of
climate change are to be avoided, the UN-backed Intergovernmental Panel on Climate
Change (IPCC) said in its synthesis report released in Copenhagen on Sunday. It
said if all nations failed to bring emissions of greenhouse gases to nearly
zero by year 2100, climate change would leave " "severe, widespread
and irreversible impacts".