A new report from the American advisory firm Rhodium Group states that in 2019 China released more emissions than the 37 members of the Organisation for Economic Co-operation and Development (OECD), which include the US, and many members of the European Union among several other countries across the world.

Based on their data, China contributed to 27 percent of the total emissions for the year, followed by the US with 11.4 percent, India at 6.6 percent, and the European Union with 6.4 percent. Across the OECD countries, the quantity of emissions has remained roughly constant across the last three decades, with China only steadily climbing across the same time until 2019 when it moved ahead.

The analysis looked at the emissions of the so-called six Kyoto greenhouse gases: carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride. These gases have different potencies when it comes to the greenhouse effect. For example, methane is 25 times more efficient at trapping heat compared to carbon dioxide, so the combined emissions were given in terms of million metric tons of CO2 equivalent.

Before 1990, the OECD countries were already releasing more than 14,000 million metric tons of CO2 equivalent every year. China passed this threshold two years ago, emitting 14,093 million metric tons of CO2 equivalent. That's 36 million metric tons more than all the OECD countries combined.

The estimate in the report follows the United Nations Framework Convention on Climate Change, but it is important to look at other metrics given. For example, how many of the products produced in the Asian country were destined for the Western market? A “consumption” base estimate (where the emission from the imported goods are added and the ones from the exports subtracted) reduce China’s total contribution to 25 percent of the global total.

And it is not just import and export that alters the perspective. With a population of over 1.4 billion people, China’s per capita emission is 10.1 tons per year. This is less than the average for people in the OECD block (10.5 tons per person per year) and significantly less than the US, where the per capita emission is the highest in the world with 17.6 tons per year.

That said, this could change in the report for 2020. As the world faced the COVID-19 pandemic, China’s emission grew by 1.7 percent while almost all other nations declined sharply.

It is also important to look at historical data given the climate crisis is the result of over two centuries of greenhouse emissions. Focusing on OECD as a single block, they are responsible for four times the emissions from China. This is a simplistic approach given the fact that greenhouse gases are slowly removed from the atmosphere over time (but not quickly enough, unfortunately) and the issue grows ever more complex when you consider how the responsibility for greenhouse emissions has moved around over time.

The US is by far the single nation that has contributed the most to the global cumulative emission, being responsible for 25 percent of the total.