Record High for Global Greenhouse Gas Emissions

1914New Worldwatch Institute report critically examines global greenhouse gas emissions

Washington, D.C.----The disappointing climate conference in Warsaw, Poland-which was intended to lay the groundwork for a global climate agreement in 2015-stands in sharp contrast to the continued growth in emissions of greenhouse gases. Negotiators and activists alike confront not only the fact that carbon dioxide (CO2) emissions reached the highest annual total to date, but also a shifting geographic distribution of emissions. The international community must take swift action, concludes a new Vital Signs Online trend released by the Worldwatch Institute (

According to the Global Carbon Project, CO2 emissions from fossil fuel combustion and cement production reached 9.7 gigatons of carbon (GtC) in 2012, with a ±5 percent uncertainty range, and may reach 9.9 GtC in 2013. The 2012 value is 58 percent higher than emissions in 1990, the year often used as a benchmark for emissions trends. Coal (43 percent) and oil (33 percent) accounted for the majority of these emissions, with natural gas (18 percent), cement production (5 percent), and flaring (1 percent) making up the remainder.

Recent U.S. government and World Bank moves to limit international financing for new coal projects signal a desire to shift away from this particularly carbon-intensive resource. For now, however, coal remains a major driver of CO2 emissions, accounting for 54 percent of the emissions increase in 2012. Coal use is rising in countries currently undergoing energy sector transitions. Coal-related emissions increased in Germany (4.2 percent) and Japan (5.6 percent)-both of which are phasing out nuclear power plants. Oil, gas, and cement accounted for 18 percent, 21 percent, and 6 percent of the global increase in 2012 respectively.

Although CO2 is the primary greenhouse gas emitted through human activities, it is not the only one with significant warming effects. Other major long-lived greenhouse gases include methane (CH4), nitrous oxide (N2O), and chlorofluorocarbons (CFCs). Each gas's contribution to climate change depends on such factors as the length of time it remains in the atmosphere, how strongly it absorbs energy, and its atmospheric concentration.

Fossil fuel combustion, together with deforestation and land use change, has pushed the mean atmospheric concentration of CO2 to approximately 393.9 parts per million (ppm) in 2012, an increase of more than 40 percent since 1750 and of 24 percent since the Scripps Institution of Oceanography began keeping detailed records in 1959. Scientists have suggested that the CO2 concentration will need to be reduced to at least 350 ppm if we hope to maintain a climate similar to that which has supported human civilization to date. Atmospheric CO2 concentration increased by 2.2 ppm in 2012 alone, exceeding the average annual increase over the past 10 years. And the Scripps Institution's measurements indicate an average of 396.2 ppm for the period of January to September 2013, implying an even greater increase this year.

Although the parties to the United Nations Framework Convention on Climate Change agreed in 2010 that the increase in average global temperature since the pre-industrial period must be kept below 2 degrees Celsius, many projections now put the climate on track for warming that is significantly above that. The Global Carbon Project foresees a "likely" increase in temperature of 3.2-5.4 degrees Celsius. A World Bank report projects an approximate 20 percent likelihood of exceeding a 4 degrees Celsius increase by 2100 if current mitigation commitments and pledges are not fully implemented.

Emissions data also highlight the shifting geographical and historical complexity that makes international negotiations so contentious. The global distribution of emissions in 2012 looked very different than it did in 1990, when the Kyoto Protocol was established. At that time, industrial countries accounted for 62 percent of emissions; by 2012, that figure had dropped to 37 percent, reflecting rapid industrialization and development in emerging economies and shifting patterns in production and consumption.

Additionally, although international climate negotiations have focused traditionally on the role and responsibility of nation states, new analyses point to the significant role of corporate entities in emitting greenhouse gases. According to painstaking work by Richard Heede of the Climate Accountability Institute, investor-owned corporations have been responsible for 21.7 percent of CO2 and CH4 fossil fuel and cement emissions since 1750, with state-owned corporations responsible for an additional 19.8 percent, highlighting potential new ways to frame responsibility for climate mitigation.

As climate negotiators, experts, and activists leave Warsaw and gear up to work on forging a global deal in Paris in 2015, they will have to grapple with these changing complexities.

Further highlights from the report:

  • CH4 is the third most abundant greenhouse gas in the atmosphere, after CO2 and water vapor, on a per molecule basis. Although atmospheric CH4 levels declined during 1983-99 and remained relatively constant during 1999-2006, they have been increasing since 2007.

  • China's emissions rose by 5.9 percent in 2012, an increase that accounted for 71 percent of that year's global increase. The United States and Australia, although both still major emitters, experienced reductions of 0.05 percent and 11.6 percent respectively.

  • In 2012, the top four emitters of CO2 were China (2,626 million tons of carbon, or MtC), the United States (1,397 MtC), India (611 MtC), and the Russian Federation (492 MtC).

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