The latest Intergovernmental Panel on Climate Change report makes for gloomy reading. The world needs 'drastic changes' to reduce carbon emissions and prevent global temperature rises, reports the ABC; investment in renewable energy needs to triple, says the BBC; the emissions problem is outrunning political determination to tackle it, says the NY Times.

True, there is also a hint of optimism in much of the reporting, because the IPCC itself says the cost of tackling climate change need not be crippling. But there are a lot of 'ifs' and 'buts' attached to that optimism, often corralled around the phrase 'political will': if there's enough of it, we can crack the climate change problem. 'Political will' is one of the most beguiling phrases in politics but should always be distrusted. The unstated subtext is that political leaders just need to lay aside their national interest and see the 'bigger picture'. That of course almost never happens, particularly if the threat is as nebulous as climate change.

Still, if you're looking for true starry-eyed optimism, I recommend this piece from Ambrose Evans-Pritchard, who argues that solar energy is improving so fast that it could overturn the global energy economy in a decade:

For the world it portends a once-in-a-century upset of the geostrategic order. Sheikh Ahmed-Zaki Yamani, the veteran Saudi oil minister, saw the writing on the wall long ago. "Thirty years from now there will be a huge amount of oil - and no buyers. Oil will be left in the ground. The Stone Age came to an end, not because we had a lack of stones, and the oil age will come to an end not because we have a lack of oil," he told The Telegraph in 2000.

I'm sceptical. If there's a lot of surplus oil, it will be cheap, and at lower prices it will find a whole new market. It's great that renewables are getting cheaper, but if that only serves to drive down the cost of fossil fuels, it will be wasted effort. As renewables get cheaper, fossil fuels need to get more expensive. If only there were a market-based mechanism to achieve that aim...

Photo by Flickr user Johan Douma.