[T]he quantity-based Kyoto-type approach [to UN climate negotiations] has pretty much broken down, leaving the world with a highly non-optimal patchwork of sporadic regional volunteerism that does not address centrally how to correct the critical externality of global warming. — Harvard economist Martin Weitzman.
The Kyoto Protocol is broken. What can replace it? Professor Weitzman, considered one of the world’s most influential economists, proposes a game change: Instead of squabbling over the quantity of fossil fuels each nation may burn, negotiate a single carbon price all can adhere to.
Weitzman is best known for modelling the economics of catastrophic climate change. In a ground-breaking 2009 paper, he demonstrated that conventional cost-benefit analysis under-weights the risk of catastrophic scenarios. In two new papers, he scrutinizes the Kyoto Protocol’s quantity-based structure through the lens of game theory. He calls Kyoto’s attempt to set and divvy up a global emissions cap “the ultimate… top-down worldwide treaty.” That’s not a compliment. Observing that Kyoto hasn’t come close to its goal of “an internationally harmonized binding system of emissions caps,” Weitzman shows why: the Kyoto framework induces each nation to game the system by attempting to maximize the efforts required of others while minimizing its own.
Weitzman lays out three criteria for an effective global emissions reduction system:
1. It should induce cost-effective emissions reductions.
2. It should allow negotiators to focus on negotiating one central and highly salient parameter.
3. It should align negotiators’ incentives toward internalizing climate costs.
On the first criterion, Weitzman points out that while a carbon tax is more easily administered and more transparent than a cap-and-trade system, a carbon cap or a tax can both achieve cost-effective emissions reductions.
On the second, Weitzman builds on Nobel-laureate Thomas Schelling’s pioneering game theory analysis establishing the importance of a clear focal point in negotiations. Kyoto’s quantity-based approach assigning different binding emissions quotas to each nation has no focal point. In contrast, a price-based negotiation offers a single focal point for all parties.
And building on the seminal work of Ronald Coase, Weitzman stresses the importance of minimizing transactions costs. Coase showed that parties that might otherwise negotiate an agreement can be deterred by the high costs of getting to yes. Weitzman points out that any quantity-based structure such as Kyoto necessarily multiplies transaction costs: “It is easier to negotiate one price than n quantities — especially when the one price can be interpreted as ‘fair’ in terms of equality of effort,” he writes.
The bulk of Weitzman’s analysis focuses on his third and most important criterion: the need to negotiate a structure that counteracts parties’ national self-interests and aligns their incentives toward reducing emissions. [Read more…]