The Intergovernmental Panel on Climate Change has this week set out both a rosy and a black vision of our green future.
With the right governmental backing we could get almost 80 per cent of our energy from renewable energy sources by 2050, according to an IPCC report. This super-green scenario assumes we become so energy efficient that the predicted 9-billion-strong population of 2050 uses less energy than 7 billion of us do today - 407 exajoules per year, compared with 490 exajoules.
The report says that the renewable energy sector is growing fast due to government support, and that its energy would be "economically attractive" if the environmental costs of fossil fuel emissions were included in prices.
But the report also offers another vision. Without green support we could consume 749 exajoules ...
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