Countries are turning to coal-fired power after renewables failed to keep pace with a post-pandemic jump in demand for energy.
Carbon dioxide emissions are heading towards their second largest annual increase in history, the International Energy Agency (IEA) warned on Wednesday, as coal makes an unlikely comeback.
The news comes as a blow to politicians who have ramped promises for their economies to reach net zero carbon emissions.
Dr Fatih Birol, executive director of the IEA, warned that progress in clean energy is still “far too slow”, and governments need to use the Cop26 conference in Glasgow in November to give a “clear and unmistakable signal” about their commitment.
In a stark warning, the IEA says that, under current measures governments have put in place to curb emissions, global temperatures will hit 2.6 degrees – and rising – above pre-industrial levels in 2100.
If all net zero emissions pledges announced by governments so far are met on time, the temperature rise will be held to 2.1 degrees centigrade.
Both of those forecasts overshoot the international Paris Agreement of 2015 to limit global warming to below two degrees.
“The world’s hugely encouraging clean energy momentum is running up against the stubborn incumbency of fossil fuels in our energy systems,” Dr Birol said.
“Governments need to resolve this at COP26 by giving a clear and unmistakable signal that they are committed to rapidly scaling up the clean and resilient technologies of the future.
“The social and economic benefits of accelerating clean energy transitions are huge, and the costs of inaction are immense.”
The IEA said electricity demand has climbed this year well-above pre-pandemic levels, with demand in China already 10pc higher than in 2019.
Renewable power is on course for a second record year of growth, but this falls short of demand, with “much of the residual increase being met by increased output from coal-fired plants in Asia,” it added.
Global energy-related carbon dioxide emissions are set to rise by 1.2bn tonnes in 2021, a 4pc increase which wipes out two-thirds of the fall in 2020. Climbing electricity demand and coal-fired generation accounts for nearly a third of this.
The analysis is part of the IEA’s annual World Energy Outlook, published on Tuesday amid a global crunch in coal and gas supplies which is pushing up prices around the world.
The IEA says these price spikes are “not related to efforts to transition to clean energy” but warns of further volatility ahead without greater investment.
“It is hard to understate the dangers inherent in today’s shortfall in spending on clean energy transitions, compared with the levels required,” it says.
“If we do not correct it soon, the risks of destabilising volatility will only grow as we move forward.”