Concerns about the climate change impact of burning the world's remaining oil resources mean the reserves will never be fully exploited, BP chief economist Spencer Dale said.

That assumption means the relative price of oil will not necessarily increase over time, Dale said at an economists' conference in London.

Burning existing reserves of oil, gas and coal would emit more than 2.8 trillion tonnes of climate-harming carbon emissions, much more than the 1 trillion threshold scientists have set to limit global warming to 2 degrees.

"Concerns about carbon emissions and climate change mean that it is increasingly unlikely that the world's reserves of oil will ever be exhausted," Dale said.

BP is among the world's top oil producing companies but it is also part of a group of energy firms that has called for the creation of a global carbon pricing mechanism that would limit investments in climate-harming forms of energy.

Technological advances will also reduce the cost to extract harder-to-reach resources, Dale said. - Reuters