Couertsy: iea.org

Global energy-related CO₂ emissions grew 1.7% in 2018 to reach a historic high of 33.1 Gt CO₂. It was the highest rate of growth since 2013, and 70% higher than the average increase since 2010. Last year’s growth of 560 Mt was equivalent to the total emissions from international aviation.

The increase in emissions was driven by higher energy consumption resulting from a robust global economy, as well as from weather conditions in some parts of the world that led to increased energy demand for heating and cooling.

CO₂ emissions stagnated between 2014 and 2016, even as the global economy continued to expand. This decoupling was primarily the result of strong energy efficiency improvements and low-carbon technology deployment, leading to a decline in coal demand. But the dynamics changed in 2017 and 2018. Higher economic growth was not met by higher energy productivity, lower-carbon options did not scale fast enough to meet the rise in demand.

The result was that CO₂ emissions increased by nearly 0.5% for every 1% gain in global economic output compared with an increase of 0.3% on average since 2010. Renewables and nuclear energy have nonetheless made an impact, with emissions growing 25% slower than energy demand in 2018.

For the first time, the IEA assessed the impact of fossil fuel use on global temperature increases. It found that CO₂ emitted from coal combustion was responsible for over 0.3°C of the 1°C increase in global average annual surface temperatures above pre-industrial levels. This makes coal the single largest source of global temperature increase.

The global average annual concentration of CO₂ in the atmosphere averaged 407.4 ppm in 2018, up 2.4 ppm since 2017. This is a major increase from pre-industrial levels, which ranged between 180 and 280 ppm.

In fact, coal-fired power plants were the single largest contributor to the growth in emissions observed in 2018, with an increase of 2.9%, or 280 Mt, compared with 2017 levels, exceeding 10 Gt for the first time.

As a result, coal-fired electricity generation accounted for 30% of global CO₂ emissions. The majority of that generation is found today in Asia, where average plants are only 12 years old, decades younger than their average economic lifetime of around 40 years.

Despite growth in coal use, fuel switching between coal and gas accelerated in 2018, reducing the carbon intensity of global energy use. Driven by economics and policies, coal-to-gas switching avoided almost 60 Mt of coal demand, with the transition to less carbon-intensive natural gas helping avert 95 Mt of CO₂ emissions. Without this coal-to-gas switch, the increase in emissions would have been more than 15% greater. This switch, most significant in China and the United States, reduced emissions by 45 Mt and 40 Mt, respectively.