Emissions

Energy-related industries are major sources of greenhouse gas emissions, with the power industry the largest contributor by far, accounting for some 40 percent of total emissions. This is primarily due to the use of coal, which is both the largest source of electricity generation and the largest single source of CO₂ emissions worldwide. Because of this, many countries are phasing out coal and shifting toward cleaner energy sources in a bid to cut down emissions.

The upward trend in global emissions has led to a substantial build-up of GHGs in the atmosphere. Levels of CO₂ have reached record highs in recent years, with global average annual concentrations climbing above 420 parts per million in 2023. This represents an increase of more than 50 percent above pre-industrial CO₂ levels. Average atmospheric abundances of methane (which has a greater warming potential than CO₂) have also hit record highs in recent years.

Rapid economic growth in recent decades has seen China become the world’s largest GHG emitter. Responsible for almost 30 percent of annual global climate pollution, China’s emissions are now twice those of the world’s second-largest emitter the United States. Nevertheless, the United States is the biggest emitter in history, having produced a quarter of total CO₂ emissions since the Industrial Revolution.

The increase in fossil fuel combustion has not only warmed the planet, but has also worsened air quality around the world. Many countries, particularly in developing regions, are exposed to poor air quality, with some of the most polluted recording air pollution levels that far exceed the limits advised by the World Health Organization (WHO). Air pollution is now one of the leading causes of premature deaths worldwide, cutting millions of lives short every year.