"Trade negotiators can emulate the progress made in the climate change agreements by moving away from a simplistic division between developed and developing countries."

"While some of these so-called complementary policies can be valuable under particular circumstances, they can also create severe problems. An example of this is the attempt to employ aggressive sector-based targets through technology-driven policies, such as the Low Carbon Fuels Standard (LCFS). In the presence of the cap-and-trade regime, the LCFS has the perverse effect of relocating carbon dioxide (CO2) emissions to other sectors but not reducing net emissions, while driving up statewide abatement costs, and suppressing allowance prices in the cap-and-trade market, thereby reducing incentives for technological change."

Was the Paris Climate Conference of 2015 a key step in stopping climate change? We asked the Belfer Center's Robert Stavins and David Keith to give us their answers to that question. They agreed to disagree in some of their answers and comments.

"I respect what the Pope says about the need for action, but his unfortunate attack on the use of the market to address climate change is out of step with the thinking and the work of informed analysts and policymakers around the world, who recognize that we can do more, faster, and better with the use of market-based policy instruments — carbon taxes and cap-and-trade systems."

"There has been more progress on discussions in the corridors, if not in the negotiations, regarding the eventual legal status of the agreement. The French have now recognised publicly that their previous position arguing that the entire agreement, including the numerical contributions in the INDCs, be binding under international law is simply not feasible. Among other things, it would mean that the Paris Agreement would require Senate ratification in the United States, which means that the United States would not be a party to the agreement. No one wants to repeat the Kyoto Protocol experience."

"For many years, negotiators at the annual conferences of the United Nations Framework Convention on Climate Change looked longingly at how the World Trade Organization was able to negotiate effective international agreements. Ironically, the Paris climate talks that are scheduled to conclude on Friday and the WTO negotiations, which will take place next week in Nairobi, lead to the opposite conclusion. Trade negotiators should emulate the progress made in the climate change agreements by moving away from a simplistic division between developed and developing countries."

"The role of market mechanisms for reducing greenhouse-gas emissions and the relationship between climate change policy and international trade were the topics of a side-event panel discussion on Friday at the Conference of the Parties (COP21), the United Nations Conference on Climate Change in Paris. The panel discussion, which was co-sponsored by the Harvard Project on Climate Agreements, addressed a variety of issues related to the emissions-reduction targets that countries are putting forward as part of a new agreement to be concluded in Paris."

The authors summarize the past thirty years of cap-and-trade programs throughout the world and explore future applications of market-based approaches to reducing emissions.

"In addition to U.S. moves toward curbing carbon emissions, international attention on the issue is far more substantial than it was at the time of the 1997 Kyoto Protocol, according to panelists. That agreement covered just 14 percent of global carbon emissions, Stavins said. Countries responsible for 90 percent of today's emissions have already committed to voluntary reductions in advance of the Paris talks."