Confusion over the types of coal being burned in Chinese power stations has caused a significant overestimation of the country’s carbon emissions.

Researchers, published in the journal Nature, say existing CO2 calculations had used a globally averaged formula.

But when scientists tested the types of coal actually being burned in China, they found they produced 40% less carbon than had been assumed.

The study says the error amounted to 10% of global emissions in 2013.

China’s drive for economic growth over the past 15 years has seen the rapid expansion of coal burning for the production of energy.

Indeed, the widely quoted statistic about the country building a new coal power station every week was actually exceeded in 2006, when one and a half such plants were constructed on average.

That rate of expansion has fallen away but this reliance on coal means that China’s emissions of carbon dioxide topped the rest of the world for the first time back in 2007, a position it has retained ever since.