Nearly 200 countries gathered in Copenhagen to try to put a cap on carbon emissions.

But when it comes to curtailing the greenhouse gases that contribute to global warming only a handful really count.

Indeed, the dozen biggest GHG emitting nations — a select group that includes Canada — account for nearly 80 per cent of the nearly 29 trillion tonnes of carbon dioxide and related gases that are released into the atmosphere each year as a result of human activity.

If this top group alone could come to some agreement to curtail GHG emissions, the world might rest a little easier. But they are a diverse lot of developing-world manufacturing giants and waning industrial superpowers, all with different energy needs and resource bases.

Clicking on the navigation bar on the interactive map below will give you a better sense of this diversity and also outline the emission cuts the "dirty dozen" are proposing for 2020, which has been the next target date for a post-Kyoto world.

The full table can be found at the bottom of the page.

The standard measure for GHG emissions is MtCO2e, which stands for megatonne — a million tonnes — of carbon dioxide (the main greenhouse gas) and its equivalent in related gases.

How much is a megatonne of CO2? By volume, it would be enough gas to fill a million two-storey homes, according to Statistics Canada.

Average annual Canadian temperatures. (Statistics Canada)Average annual Canadian temperatures. (Statistics Canada)

When it comes to the international politics of climate change, however, three other elements should probably be kept in mind — historical perspective, per capita emissions and so-called carbon intensity, which varies considerably depending on each country's primary energy resources.

Developing nations such as China and India argue strenuously that it has been the industrialized West, the U.S. and Europe in particular, which has been responsible for the vast bulk (70 per cent) of the emissions over the past 60 years and that they now deserve the chance to better their own standards of living.

It is a potent argument. But at the same time, China alone is poised to add 75,000 to 100,000 MtCO2e of GHG over the next decade, even with its proposed efficiencies.

When it comes to per capita emissions, it is the oil and coal producing nations, such as the Gulf States and Canada, which rank highest. (Take away Canada's export-driven oil and gas industry, for instance, and we would not be in the top 12.)

Some experts suggest a per capita emission quota of between three and five MtCO2e a year, which would allow for growth in much of the developing world, might be the fairest way to bridge the gap.

Others, though, say it will take a combination of hard caps on the big emitters as well as per capita and carbon intensity targets if there is to be any kind of workable agreement between such a diverse group.

The Dirty Dozen: top 12 GHG emitters in 2005

MtCO2e World emissions % Change since 1990 % Tonnes per capita (rank) Projected emissions in 2020
China 7,234.3 19 + 101 6 (n/a) 10,914

U.S.

 6,931.4 18 + 16 23.6 (3) 5,902
Europe 5,049.2 13 - 6 10.4 (22) 3,368
Russia 1,947.4 5 - 34 15.4 (8) 2,489
Brazil* 2,022 5.2* - 20 4 (n/a) n/a
India 1,866.1 4.9 + 69 1 (n/a) n/a
Japan 1,356.2 3.6 + 14 10.8 (18) 952
Germany 975.2 2.6 - 18 11.6 (17) 972
Canada 739.3 2 + 27 22.7 (4) 577
U.K. 645 1.7 - 9 10.5 (20) 619
Italy 562.4 1.5 + 12 9.3 (27) 413
Australia 559 1.5 + 39 25.8 (2) 414

Sources: World Resources Institute, World Bank, International Energy Association for 2005, the most recent year for which data on all six greenhouse gases is available.

*Unlike the others, Brazil's emission number includes land-use emissions, to reflect the vast clearing in the Amazon region. On an industrial basis alone, its emissions are lower than Russia's and possibly India's.

Note: As a result of the Copenhagen climate conference in December 2009, some of the annual emissions estimates have been restated and are reflected in this updated table. Some agencies now suggest that Mexico, Indonesia and South Korea have vaulted ahead of Italy and Australia in these most current rankings.

Corrections and Clarifications

  • Because of a mathematical error we inadvertently underestimated the percentage change in China's and India's greenhouse gas emissions over the most recent 15-year period. We originally reported that China's GHG emissions increased 52 per cent since 1990 while India's went up by 45. In fact, China's increase was 101 per cent over that period while India's was 69 per cent. In the process of correcting this, we discovered that our primary sources had recently restated these annual emission numbers, including those for China and India, as a result of new information that came out at the UN's Copenhagen climate summit in December 2009. As a result, we have updated our list of the world's top GHG emitters with the most current information. Dec. 22, 2009.