Transition to clean energy is inevitable over the next generation, but we need immediate, rapid change to avoid the impacts of climate change.

That the world is engaged in a profound transition in the way we use energy is undeniable. The era of carbon-intensive energy derived from the burning of fossil fuels is coming to an end, and a cleaner, more reliable energy future based on renewables like wind and solar will be the new normal. How long this change will take is, however, still a matter of fierce debate. But a new report from the World Economic Forum’s Global Future Council on Energy, offers compelling evidence that stakeholders in the global energy system —which means all of us—must prepare for change urgently, because it is coming fast. The report, principally authored by Kingsmill Bond of Carbon Tracker, Angus McCrone of Bloomberg NEF, and myself, examines a key question: will the energy transition be gradual or rapid? A gradual transition means that oil, gas, and coal remain the dominant energy sources even as renewable energy supply increases at a steady but linear rate. And it means that there is growth in energy demand for fossil fuels—with demand for fossil fuels not reaching its peak for a generation or more—allowing the traditional businesses of energy sector incumbents to continue to flourish. In this transition scenario, we miss the climate change goals of the Paris Agreement, but the global energy sector doesn’t face the near-term prospect of wrenching change. A rapid transition, on the other hand, means that renewables like wind and solar quickly start to supplant fossil fuels as their supply increases at an exponential rate, following the familiar S-curve growth pattern of new technologies like personal computers and mobile phones. It means that renewables supply all the net growth in global electricity demand, displacing oil, gas, and coal —with demand for fossil fuels peaking in the 2020s —and thus seriously disrupting the traditional businesses of the energy sector incumbents. In the rapid transition scenario, the energy sector will face massive change, but humanity has a chance of achieving the goals of the Paris Agreement to limit climate change to well below 2 degrees. The question of the timing of the energy transition is a critical one: either the tipping point is right before our eyes in the decade to come, or it is far into the future, beyond the planning horizon of most companies.