World leaders are meeting Tuesday at the United Nations for a summit that is intended to set the stage for global negotiations later this year in Lima and next year in Paris, to reduce greenhouse gas emissions and the threat of global climate change. The negotiations are at an important crossroad.

Twenty years ago at the original “Earth Summit” in Rio de Janeiro, the nations of the world enacted the UN Framework Convention on Climate Change and established two key principles. One was the goal of stabilizing greenhouse gas concentrations in the atmosphere. The other was that the governments should protect the climate system “on the basis of equity and in accordance with their common but differentiated responsibilities and respective capabilities.”


This second principle signaled the conviction that although the climate problem is a global issue, with all countries contributing, rich nations had historically contributed more to the atmospheric stock of greenhouse gases than others. Listed in Annex I of the Convention, the wealthy nations were committed to take actions.

Krishna Dasaratha | 5/8: Harvard should cut hypocrisy, divest from fossil fuels

In the first decision of the first Conference of the Parties of the UNFCCC, the global community agreed to the Berlin Mandate, which interpreted “common but differentiated responsibilities” as meaning that the Annex I countries alone would take on emission-reduction responsibilities. The Berlin Mandate, codified with numerical national targets and timetables in the 1997 Kyoto Protocol, produced a dramatic gap between rhetoric and reality.

By the time of the Berlin Mandate, greenhouse gas emissions of non-Annex I countries surpassed those of Annex I countries. By 2005, when the Kyoto Protocol entered into force, per capita fossil fuel CO2 emissions of nearly 50 non-Annex I countries exceeded those of the Annex I country with the lowest per capita measure. The six largest greenhouse gas emitters were not constrained by the Kyoto Protocol, because of lack of commitments (China, India, Brazil, and Indonesia), the non-binding nature of its emission commitment (Russia), or failure to ratify the agreement (United States).


Since 1990, the base year of the Kyoto Protocol, emissions have grown by approximately 5 percent annually in the non-Annex I countries, while remaining about flat in the Annex I nations.

Furthermore, the dichotomous structure effectively quadrupled the global cost of emission abatement necessary to stabilize atmospheric concentrations of greenhouse gases, relative to a cost-minimizing scenario.

But prospects for change began to emerge in 2009, when annual negotiations led to the Copenhagen Accord, followed in 2010 by the Cancun Agreements, which together blurred the distinction between Annex I and non-Annex I.

An even greater departure from that dichotomy arose from negotiations in 2011 in Durban, South Africa, where agreement was reached on a structure focused on the participation of all parties in the effort to mitigate greenhouse gas emissions. Under the Durban Platform for Enhanced Action, delegates agreed to craft a future legal regime that would be “applicable to all Parties . . . under the Convention.” This presented the potential to essentially eliminate the Annex I/non-Annex I distinction, and was therefore an important step toward breaking the logjam that has prevented progress.

The goal now before negotiators is to produce a new international agreement — under the Durban Platform — in Paris in 2015, for implementation in 2020, as a successor to the Kyoto Protocol. This presents the greatest opportunity the world has had in 20 years to make meaningful progress on this exceptionally challenging issue. The UN summit in New York can accelerate the momentum toward such a new, path-breaking approach.

Robert N. Stavins is professor of business and government at the Harvard Kennedy School, research associate at the National Bureau of Economics Research, and university fellow at Resources for the Future.