Which countries and industries emit the most greenhouse gases?

The annual UN climate summit runs from November 9 to 20, 2026, as delegates confront alarming data showing greenhouse gas emissions continue to climb worldwide. These emissions, primarily carbon dioxide and methane, trap heat in the atmosphere, fueling extreme weather conditions including heatwaves, droughts, and floods that have caused widespread devastation.

In 2025, carbon dioxide made up 73.8 percent of global greenhouse gas emissions, released mainly through fossil fuel combustion. Methane accounted for 17.6 percent, followed by nitrous oxide at 5.3 percent and fluorinated gases at 3.3 percent. Global CO2 emissions have risen by 76.3 percent since 1990, according to the European Commission's Joint Research Centre.

Extreme weather consequences

The warming planet has already produced devastating effects in 2026. The World Meteorological Organization reports that extreme weather has killed tens of thousands and forced millions from their homes. In Europe, heatwaves, droughts and wildfires between May and August caused more than 30,000 excess deaths, with 220,000 people evacuated in France alone.

In August, a glacier collapse in the Himalayas triggered flash floods that killed over 1,500 people in Nepal along its border with China, while approximately 5,600 remain missing. Earlier in the year, Typhoon Bavi forced three million people to evacuate in China and killed 26 in the Philippines, while Tropical Storm Maysak killed 171 people and caused over $3 billion in losses in China.

Emissions by sector

The power industry is the largest source of greenhouse gas emissions, producing nearly 30 percent globally in 2025. Its emissions have roughly quadrupled since 1970, driven by soaring electricity demand in fast-growing economies. Industry, including manufacturing and mining, is the second-largest source at 21 percent, followed by transport at 16 percent. Together, these three sectors produce about two-thirds of the world's emissions.

The remaining emissions come from agriculture (12 percent), fossil fuel extraction (11 percent), buildings (6.6 percent) and waste (3.6 percent). Global emissions have fallen only a handful of times since 1970, including after the 2008 financial crisis and during the COVID-19 pandemic in 2020, but each time they rebounded.

Top emitting countries

In 2025, the three largest emitters produced almost half of the world's greenhouse gases. China emitted nearly 16 billion tonnes (29.5 percent), the United States 6.02 billion tonnes (11.1 percent) and India 4.51 billion tonnes (8.3 percent). The 27 countries of the European Union together accounted for 5.8 percent, followed by Russia (4.8 percent), Indonesia (2.5 percent), Brazil (2.4 percent) and Iran (2.1 percent).

China's power sector is responsible for 42 percent of its emissions, while industry accounts for 31 percent. In September 2025, Chinese President Xi Jinping pledged to cut the country's greenhouse gas emissions by 7 to 10 percent from their peak by 2035. In the US, transport is the largest source at 29 percent, while in India, the power sector produces 35 percent of emissions.