Can 'peak oil' help slow climate change?

This is a title of a news article at the Guardian.co.uk. Peak oil raises many questions about the future of civilization. Economic and social stability is # 1 of them. Impact on climate change has not been received much attention yet: Climate change can be finally tamed down by decreased supply of fossil fuel? At a glance, it seems to be. But it is not that easy question. The article concludes that peak oil will worsen climate change because economies probably  move to cheap but dirty fossil fuels such as tar sands and shale oil. What do you think? Here is a part of the article:

indeed the longer-term impact of the oil peak could be to accelerate rather than decelerate global warming. That's because falling availability of crude oil could boost the production of even more carbon-intensive alternatives such as oil extracted from tar sands or "synfuel" produced from coal.