Writing in The Times, Jeroen van der Veer said that in terms of future energy needs, "the world needs a reality check" and will need to face three difficult truths.

In his estimation, those truths are that demand is accelerating, the growth of easily-extracted fossil fuels will not keep up with that acceleration in demand, and increased use of coal will lead to higher carbon emissions, possibly to levels that the world does not consider acceptable.

Van der Veer wrote that "taking the CO2 out of fossil fuels, especially coal, is crucial."

According to him, renewables will make up no more than 30 percent of the world's energy mix by 2050, which is "why energy efficiency is so important."

"What's the point of producing ever more energy if we continue to waste most of it? Instead, we should aim to become twice as efficient in the use of energy by the middle of the century," Van der Veer wrote.

"That is entirely feasible, provided that the will is there."

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