Peru’s president Ollanta Humala addresses climate conference attendees at the 20th Conference of the Parties (COP20) in Lima, Peru, in 2014. Ahead of the 21st Conference of the Parties (COP21) to take place this year in Paris, France, researchers have published an analysis of proposed emissions pledges by the United States, European Union, and China. Their study finds that those pledges fail to meet widely held standards for international fairness. Credit: Reuters/Enrique Castro-Mendivil

In a new study, researchers have analyzed how much countries worldwide say they’ll cut greenhouse gas emissions, finding that the pledges of the biggest emitters—the European Union (EU), United States, and China—don’t meet widely held standards for international fairness. Unless those top three emitters commit to steeper reductions in their use of fossil fuels and invest in technology development, all other nations will need to make far more heroic and self-denying cuts, the researchers conclude, to forestall dire consequences from average global warming exceeding 2°C (3.6°F) in coming decades.

If warming tops 2°C, the effects become potentially hazardous to human infrastructure, according to the United Nations Intergovernmental Panel on Climate Change: Agricultural yields could drop, diseases (especially those borne by mosquitoes) will spread more easily, people worldwide might face more drought and water shortages, and extreme weather will become more common.

Emissions Squeeze

Summarizing results of the new analysis, its lead author, Glen Peters, senior researcher at the Center for International Climate and Environmental Research–Oslo (CICERO) in Oslo, Norway, and his collaborators report that “combined, the EU, US, and Chinese pledges leave little room for other countries to emit CO2 if a 2 °C limit is the objective, essentially requiring all other countries to move towards per capita emissions 7 to 14 times lower than the EU, USA, or China by 2030.”

He and his colleagues published their analysis on 15 October in Environmental Research Letters.

“Developing countries are emitting far less per capita than developed countries do,” said atmospheric scientist Susan Solomon at the Massachusetts Institute of Technology in Cambridge, a coauthor on the new paper. In the United States, “we’re about something on the order of double the Europeans, but we’re around the order of 100 times, literally 100 times, Kenyans or Ethiopians,” she added.

Carbon released collectively by just the United States, European Union, and China through 2030 will account for 79% of the world’s allowable emissions that could keep warming below 2°C.

Under current emissions pledges, carbon released collectively by just the United States, EU, and China through 2030 will account for 79% of the world’s allowable emissions that could keep warming below 2°C, the paper’s authors conclude. But if the biggest emitters sustain that same emission rate beyond 2030, warming closer to 3°C would result by the end of the century.


Next month, a high-profile, 12-day climate meeting known as the 21st Conference of the Parties (COP21) will convene in Paris. There, national emissions pledges called independent nationally determined contributions (INDCs) will influence negotiations toward a new international climate change agreement.

In anticipation of those negotiations, the researchers investigated the relative fairness of two potential ways of divvying up emission allowances among nations: an “inertia” approach that allots to each country the same fraction of allowable emissions in the future as they have now and an “equity” approach granting each country a share of allowable emissions based on its percentage of the world’s population. The inertia approach won’t aid developing countries, the researchers concluded, because the large emitters would keep their current shares of global emissions.

If the biggest emitters “don’t put themselves on a 2°C consistent pathway, then we quickly use up our available carbon budget,” said Louise Jeffrey, a scientific researcher at Potsdam Institute for Climate Impact Research who did not contribute to the new analysis.

Equity Versus Inertia

The equity approach, which the study authors deemed more fair, would allow developing countries to emit more than they currently do, easing further economic development in those nations. But the approach could require some countries to cut emissions at an infeasible rate, the researchers warned.

Nearly 2 years ago, the body convening the Paris meeting—the United Nations Framework Convention on Climate Change (UNFCCC)—asked each country to state its INDC well in advance of COP21, which begins 30 November. Even though researchers project that the globe will overheat and see emissions distributed unfairly, Nick Nuttall, a UNFCCC spokesperson, emphasized that INDCs represent a starting point for COP21 and that negotiations will progress beyond just these pledges.

“Paris needs to send a signal to the entire world that we are now embarking on a super low-carbon trajectory.”

Nuttall added that the countries and the UNFCCC know that the INDCs currently don’t add up to an emissions reduction that will keep the globe below a 2°C warming. Today, in a press conference, UNFCCC released its own report of aggregated effects from submitted INDCs, which will provide a foundation for the Paris meeting.

“Paris needs to send a signal to the entire world, including the power sector and the energy sector, that we are now embarking on a super low-carbon trajectory,” said Nuttall.

—Cody Sullivan, Writer Intern

Citation: Sullivan, C. (2015), Targets of biggest global carbon emitters flunk fairness test, Eos, 96, doi:10.1029/2015EO038423. Published on 30 October 2015.

Text © 2015. The authors. CC BY-NC 3.0
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