A 54.1-billion-tonne snapshot: which countries and industries emit most greenhouse gases?

Emissions keep rising

The world’s greenhouse gas emissions grew from about 23 billion tonnes in 1970 to 54.1 billion tonnes in 2025, according to the JRC. Carbon dioxide and methane are the main gases described in the report; nitrous oxide and fluorinated gases also contribute.

As greenhouse gases accumulate, they trap heat in the atmosphere. The World Meteorological Organization says ocean heat reached a record high in 2025, and the pace of ocean warming has accelerated sharply over the past two decades.

The WMO also reported that extreme weather killed tens of thousands of people and displaced millions in 2026. In one event, a glacier collapse and flash flood in the Himalayas killed more than 1,500 people in Nepal near the Chinese border; about 5,600 remained missing, according to the UN.

Power and industry dominate

Power generation is the largest source of global emissions, responsible for 34 percent. Industry, including manufacturing and mining, ranks second at 21 percent, from fuel used in factories and gases released in making cement, metals and chemicals.

Together, power and industry account for more than half of global emissions. Transport contributes 15 percent, while agriculture accounts for 12 percent and extraction of coal, oil and gas for 11 percent. Buildings and waste make up 6.6 percent and 3.6 percent, respectively.

Methane made up 17.6 percent of emissions in the year referenced, followed by nitrous oxide at 5.3 percent and fluorinated gases at 3.3 percent. The article does not specify that year in this breakdown.

China leads national totals

In 2025, China emitted almost 16 billion tonnes of greenhouse gases, or 29.5 percent of the global total. The United States produced 6.02 billion tonnes, equal to 11.1 percent, and India emitted 4.51 billion tonnes, or 8.3 percent.

The three countries together produced almost half of global emissions that year. China’s emissions rose rapidly as its economy expanded in the early 2000s, and it passed the United States as the biggest emitter in the middle of that decade.

International shipping and aviation are counted separately from individual countries. Together, they generated 2.6 percent of global emissions, more than most countries.

Different sources by country

In China, power generation was the biggest source, accounting for 42 percent of its nearly 16 billion tonnes of emissions. Industry contributed 31 percent, while fuel production accounted for 9.5 percent.

In the United States, transport led at 29 percent, mostly from cars and trucks. Power generation was responsible for 26 percent, and industry for 14 percent. The article’s opening says the United States has emitted the most CO2 over history, while China is now the biggest emitter. These figures refer to different measures: cumulative carbon dioxide emissions and annual greenhouse gas emissions in 2025.