Wind and solar expansion helped bring an unexpected stall to the growth of global energy-related CO2 emissions last year, said the International Energy Agency (IEA) as it urged the world to make sure 2019 is a “peak and not a pause”.

Energy-related CO2, the largest source of emissions globally, stayed flat at 33 gigatonnes last year after growing in 2017 and 2018, despite a 2.9% expansion in the world economy, said the IEA.

The global energy organisation said the flatlining came against expectations and “was primarily due to declining emissions from electricity generation in advanced economies, thanks to the expanding role of renewable sources (mainly wind and solar), fuel switching from coal to natural gas, and higher nuclear power generation”.

Continued growth in emissions despite massive investments in renewables over the last 10 years was a major cause of concern over progress of the energy transition.

IEA executive director Fatih Birol said: “We now need to work hard to make sure that 2019 is remembered as a definitive peak in global emissions, not just another pause in growth,” adding that the organisation is building a “grand coalition” of governments, business and investors to that end.

The IEA’s data reveals a stark contrast between trends in ‘advanced economies’, where the body said power-sector emissions “declined to levels last seen in the late 1980s”, and other parts of the world. Coal generation in richer nations was down almost 15% year-on-year thanks to renewables growth and lower demand.

The US recorded the largest emissions decline of any nation, with a fall of 140 million tonnes, or 2.9%. The EU as a whole pushed down emissions by 5%, or 160 million tonnes, and Japan also saw a 4% fall – although in its case the decline was heavily driven by nuclear restarts.

However, emissions in the rest of the world grew by close to 400 million tonnes in 2019, with almost 80% of that in Asia where coal generation is still rising, warned the IEA.

The IEA’s emissions update came as Recharge reported warnings by global consultancy Capgemini that a mass roll-out of renewables is not a “silver bullet” to fix climate change.