Demand for climate-warming fuels like coal, oil and natural gas will likely peak before 2030, evidence of the accelerating global shift to energy that doesn't emit greenhouse gasses, according to the International Energy Agency (IEA)'s World Energy Outlook. From a report: "The transition to clean energy is happening worldwide and it's unstoppable. It's not a question of 'if', it's just a matter of 'how soon' -- and the sooner the better for all of us," said Fatih Birol, IEA executive director, in a statement. The agency represents countries that make up more than 80% of global energy consumption. The annual IEA report estimates that in 2030 there will be 10 times as many electric vehicles on the road worldwide and 50% of the cars sold in the United States will be electric. The agency says solar panels installed across the globe will generate more electricity at the end of the decade than the U.S. power system produces now. And the report projects that renewable energy will supply 50% of the world's electricity needs, up from about 30% now.

But the report warns the pace of the transition will have to quicken considerably in order to limit global warming to 1.5 degrees Celsius, or 2.7 degrees Fahrenheit, and avoid some of the worst case scenarios in a changing climate. The IEA's outlook lays out a strategy for meeting that goal that includes tripling renewable energy, doubling energy efficiency measures and slashing methane emissions from fossil fuel operations by 75% by 2030. Methane has more than 25 times the climate-warming potential of carbon dioxide, according to the Environmental Protection Agency. Climate and anti-fossil fuel groups say the IEA's methane strategy should be even more aggressive.