• The International Energy Agency pinpoints coal use as being the main driver behind the growth.
• Even though coal use jumped, the IEA also notes how renewables and nuclear managed to supply a bigger share of electricity generation than the fossil fuel in 2021.
• While it remains an important source of electricity, coal has a substantial effect on the environment.

Energy-related carbon dioxide emissions rose to their highest level in history last year, according to the International Energy Agency, as economies rebounded from the coronavirus pandemic with a heavy reliance on coal.

The IEA found energy-related global CO2 emissions increased by 6% in 2021 to reach a record high of 36.3 billion metric tons. In an analysis published Tuesday, the Paris-based organization pinpointed coal use as being the main driver behind the growth.

"The recovery of energy demand in 2021 was compounded by adverse weather and energy market conditions – notably the spikes in natural gas prices – which led to more coal being burned despite renewable power generation registering its largest ever growth," the IEA said.

The energy agency said its estimate was based on fuel-by-fuel and region-by-region analysis. Breaking its findings down, it said coal was responsible for more than 40% of overall growth in worldwide CO2 emissions last year, hitting a record of 15.3 billion metric tons.

"CO2 emissions from natural gas rebounded well above their 2019 levels to 7.5 billion tonnes," the IEA said, adding that CO2 emissions from oil came in at 10.7 billion metric tons. The emissions from oil were "significantly below pre-pandemic levels" due to "the limited recovery in global transport activity in 2021, mainly in the aviation sector."

China played a significant role in the emissions rise, according to the IEA. "The rebound of global CO2 emissions above pre-pandemic levels has largely been driven by China, where they increased by 750 million tonnes between 2019 and 2021," it said.

"In 2021 alone, China's CO2 emissions rose above 11.9 billion tonnes, accounting for 33% of the global total," it said.

Even though coal use jumped, the IEA also noted how renewables and nuclear managed to supply a bigger share of electricity generation than fossil fuels in 2021. Generation based on renewables exceeded 8,000 terawatt-hours last year, which the IEA described as "an all-time high."

While it remains an important source of electricity, coal has a substantial effect on the environment.

The U.S. Energy Information Administration lists a range of emissions from coal combustion. These include carbon dioxide, sulfur dioxide, particulates and nitrogen oxides. Elsewhere, Greenpeace has described coal as "the dirtiest, most polluting way of producing energy."

The IEA said it was now clear the economic recovery from Covid-19 had not been a sustainable one. "The world must now ensure that the global rebound in emissions in 2021 was a one-off – and that an accelerated energy transition contributes to global energy security and lower energy prices for consumers," it said.

The IEA's findings point to the Herculean task of achieving the goals laid out in the 2015 Paris Agreement and more recent Glasgow Climate Pact. While major economies are attempting to ramp up renewable energy capacity, the world remains heavily reliant on fossil fuels.

In the past few weeks, this sobering reality has been thrown into sharp relief by the Russian invasion of Ukraine, not least because Russia was the biggest supplier of both petroleum oils and natural gas to the EU last year, according to Eurostat.

On Tuesday the EU's executive branch, the European Commission, published what it called "an outline of a plan to make Europe independent from Russian fossil fuels well before" the end of the decade.  

"We must become independent from Russian oil, coal and gas," the Commission's president, Ursula von der Leyen, said. "We simply cannot rely on a supplier who explicitly threatens us."

The Commission's announcement came after the IEA said the EU should not enter into any new gas supply contracts with Russia in order to lower its dependence on Russian natural gas.