Human-caused CO2 emissions have never been so high, and the countries contributing the most are China, the United States and India. The Climate analysis indicators tool (Cait 2.0), run by the World Resources Institute, has published data on greenhouse gas emissions updated to 2011, revealing worrying figures that, at the same time, trace a well-defined picture of what governments need to do — and which ones — to stop global warming in the coming years.

It is an opportunity to give a brief historical overview from the start of measurements, in 1850. Today, compared with 160 years ago, the CO2 produced by human activities is 150 times higher. At that time, during the industrial revolution, the United Kingdom topped the CO2 rankings, followed by the United States. Then France, Germany and Belgium to round out the top five. The United States is still in second place today, though it is responsible for 266 times the emissions it produced in 1850.

Things changed, taking the shape we know today, around the 1960s, when the United States took control of the rankings, while China and its unchecked growth began to cause alarm, eventually overtaking the United States at the top in 2005. Although the Asian continent has seen an explosion in CO2 in absolute terms, the per capita figures reveal a completely different top ten. Saudi Arabia comes first, followed by the United States. Citizens of these two countries cause more than 17 tonnes of CO2 each year. A Chinese citizen and an Indian citizen, by contrast, produce (only) 6.5 and 1.5 tonnes respectively.

The 2011 picture is there for all to see. China has pulled well ahead of the United States in absolute terms (28 versus 16.5 per cent of the total), followed by India, Russia, Japan, Germany, South Korea, Iran, Canada and Saudi Arabia. These are the ten countries that together produce 78 per cent of all CO2 emitted worldwide each year. And these are the countries that, in the course of the forthcoming climate conferences, will need to do everything possible to reach an agreement to drastically reduce emissions in the shortest time possible.