How can we make oil and gas supplies last longer, as the search for other fuels continues?

Some say we'll have used half the world’s oil by 2020.

Others insist we already have.

Oil has been the engine of economic growth for most of the last century. But there is growing concern and debate about the amount of oil we have left, and how much time we have to act.

As oil reserves decline, prices will rise, and alternative fuel sources that were once considered too expensive will become more appealing. And as demand for these alternatives increases and technologies improve, prices will fall.

So how do we manage the transition of our fossil fuel economy to what comes next?

• Should we let the market decide, without any intervention?
• Should businesses and governments be investing heavily in technology to accelerate the transition?
• Should the government encourage a particular technology or path through regulation, subsidies and/or taxes?

These are not easy questions. But the sooner we all address them, the more chance we’ll have to make the transition work for everyone.