In the Foreword to World Energy Outlook-2015, I challenged the negotiators at COP21 in Paris to take sober stock of the way that the energy sector was shaping up. Pointing to the unsustainable trends in our central scenario, Paris presented the opportunity to put forward a different vision of our energy future – a world in which energy needs are fully met without dangerously overheating the planet and in a secure and affordable way.

The Paris Agreement on climate change, which entered into force in November 2016, is at its heart an agreement about energy. Transformative change in the energy sector, the source of at least two-thirds of greenhouse-gas emissions, is essential to reach the objectives of the Agreement. The changes already underway in the energy sector, demonstrating the promise and potential of low-carbon energy, in turn lend credibility to meaningful action on climate change. Growth in energy-related CO2 emissions stalled completely in 2015. This was mainly due to a 1.8% improvement in the energy intensity of the global economy, a trend bolstered by gains in energy efficiency, as well as the expanded use of cleaner energy sources worldwide, mostly renewables. An increasing slice of the roughly $1.8 trillion of investment each year in the energy sector has been attracted to clean energy, at a time when investment in upstream oil and gas has fallen sharply. The value of fossil-fuel consumption subsidies dropped in 2015 to $325 billion, from almost $500 billion the previous year, reflecting lower fossil-fuel prices but also a subsidy reform process that has gathered momentum in several countries.