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The Metric

Jun 14, 2014

Who are the largest emitters of carbon pollution?

Photo by the Foreign and Commonwealth Office on

Although climate change is a global problem, only a handful of countries are responsible for producing the majority of the greenhouse gas emissions (GHGs) that cause it. According to the World Resources Institute's Climate Analysis Indicators Tool (CAIT), the top 10 emitters contributed 78 percent of global CO2 emissions (excluding land-use change and forestry emissions) in 2011. Figure 1 shows these countries, with China responsible for 28 percent of all CO2 emissions, which is more than the 22 percent coming from rest of the world outside of the top 10 emitters. The United States is second, emitting 16.5 percent of global CO2. India in 2006 surpassed Japan and Russia in 2009 to become the fourth-largest emitter behind the European Union. South Korea, Iran, Canada and Saudi Arabia comprise fifth through the 10th largest emitters.

Figure 1. Top 10 global emitters of CO2 emissions. (Source: Johannes Friedrich, World Resources Institute. See original post here).

Taking into consideration the full range of greenhouse gases (e.g., methane), including emissions from land-use change and forestry, the global picture looks somewhat different (Figure 2). Indonesia, Brazil, and Mexico, all countries which have undergone substantial changes in forestry and land-use, enter the top 10 global emitters, displacing South Korea, Saudi Arabia, and Iran. Improvements in methodologies to estimate emissions from important sources like land-use change and forestry illustrates the importance of looking beyond fossil-fuel combustion as the only culprit of climate change. 

Figure 2. Top 10 global emitters of GHG emissions, including land-use change and forestry. (Source: Johannes Friedrich, World Resources Institute. See original post here).

How these data compare with the EPI's Climate and Energy Score

The EPI's primary aim is to measure country-level policy performance on high-priority environmental issues like climate change.  Absolute levels of CO2 or GHG emissions are often a reflection of the size of a country's economy because of where they primarily originate. Fifty-seven percent of global GHG emissions are CO2 from fossil-fuel combustion. Therefore, if we scored and ranked countries based solely on absolute emission levels, we'd unintentionally reward smaller countries or those with less-developed economies. 

Even when population or gross domestic product (GDP) are used to denominate emission levels, under-developed economies or countries with large populations like China and India receive more favorable results. Table 1, for example, presents the Top-10 performers in the Climate and Energy category in the 2012 EPI, which scored countries on COemissions per capita, per GDP, per kWh of electricity generated, and renewable electricity generation. Least-developed countries dominate the picture.


Score (out of 100)


2010 GDP per capita (in constant 2005 USD dollars)







Democratic Republic of Congo
























Costa Rica










Table 1. 2012 EPI rankings in the Climate Change and Energy category. *Denotes a Least-Developed Country or LDC, as designated by the United Nations.

For the 2014 EPI, we spent signficant time consulting with experts and reviewing existing efforts (see Climate Change Performance Index and Evaluating Policy Performance - The Climate Change Performance Index for two of these) to gauge more policy-relevant indicators of climate change performance that would do a better job than previous indicators. What we concluded was this: the climate change policy community has not yet developed a way of disentangling performance from the many factors that affect emission levels, including GDP, trade, and population. While there's been intense discussion through international processes like the UN Framework Convention on Climate Change to discuss commitments to mitigate climate emissions and impacts, there are no relevant metrics to assess whether national policies and actions are working to do so. 

In the absence of better, more policy-focused indicators, the 2014 EPI's Climate and Energy scores and rankings are a step closer to evaluating how countries are meeting their international obligations to address climate change. As we describe in the Climate and Energy issue profile, our indicators measure countries’ ability to reduce the intensity of carbon emissions over time. They are sensitive to countries’ differing policy obligations and take into consideration both economic and industrial development as a way of understanding which countries, relative to others, are performing better than others with similar levels of economic development. Indicators are weighted on a blended scale to account for what may seem to be subtle differences between countries that current classifications through the UNFCCC (e.g., "Annex I" countries) may not distinguish. 

While this approach is nowhere near ideal in that it still uses emissions data that cannot differentiate between changes in carbon intensity due to policy change or economic recession, it's closer to recognizing that the differences between countries' development and baseline emissions matter. Our methods do not outright reward least-developed or populous countries for masking emissions through low GDP or high population. We leave room for future indicators, such as adaptive capacity or resilience to climate change, that are important for all countries, but especially for small-island or coastal states that are particularly vulnerable. 

For other interesting figures that chart the historical growth of climate emissions and changes in the top emitters, see Johannes Friedrich's post, "The History of Carbon Dioxide Emissions."