A leading world's energy expert says colossal sums of money could be saved by switching from fossil fuels to renewable energy.
International Energy Agency deputy executive director Richard Jones told a seminar in Wellington the world is heading towards a six degree rise in average temperatures by 2050.
That is despite pledges by Governments to restrict the rise to two degrees and statements by scientists that a limited rise is essential.
Dr Jones said the larger rise could be averted by improving energy research for transport and buildings and reducing subsidies for fossil fuels.
He said this could save the world $100 trillion in direct costs.
But he said big changes are needed to bring this about.