On February 16, 2012, U.S. Secretary of State Hilary Clinton and environment ministers from five other countries introduced the Climate and Clean Air Coalition to Reduce Short-Lived Climate Pollutants. The Coalition’s members are the governments of Bangladesh, Canada, Ghana, Mexico, Sweden, and the United States, with the United Nations Environment Programme (UNEP) serving as secretariat. (UNEP released a major report on this topic in November 2011.) Its mission is to “catalyze new actions and highlight and bolster the work of existing efforts” to reduce emissions of especially potent greenhouse gases (other than carbon dioxide) and “black carbon,” which is one component of combustion products (“soot”) of wood, other biomass, diesel, and coal.

The gases targeted by the Coalition are hydrofluorocarbons (HFCs) and methane, both of which have much higher global-warming potential than carbon dioxide, though they are emitted in smaller quantities than CO2 worldwide. Incorporated into the definition of global-warming potential is the lifetime of a greenhouse gas in the atmosphere, and these gases are much shorter-lived than CO2 (for the most part—however, HFCs come in many varieties, and a few are quite long-lived). Black carbon works in a somewhat different manner to warm the Earth, but is also a short-lived and powerful warming agent.

Climate change is a stock, not a flow, problem. Thus, it is the concentrations of greenhouse gases in the atmosphere that determines how much they warm the Earth, not the volume of emissions during a particular time period. However, if a gas has a shorter residence time in the atmosphere, then a given amount of emissions reduction will yield a larger reduction in atmospheric concentration, over a particular time period (think bath tub with the drain half open).

The greater global-warming potential of HFCs and methane—incorporating their shorter residence time—means that these gases—along with black carbon—constitute good targets of opportunity. However, it is unlikely that the Coalition as presently constituted will make a dent in the problem of climate change, because the largest emitters of HFCs, methane, and black carbon are not members. (A good source for data on methane and HFC emissions is the World Resources Institute’s Climate Analysis Indicators Tool, but you’ll need to register to use it.)

Back to the good news: The barriers to entry for potential new members of the Coalition are low. Members are bound by a political agreement, not a treaty that requires ratification (or other forms of approval in various countries).  Compare the Kyoto Protocol of the United Nations Framework Convention on Climate Change (UNFCCC), which the United States has never ratified—and never will. The Swedish Minister of the Environment, at the launch on February 16, indeed stated that the Coalition will try to expand membership before the first formal meeting in Stockholm in April 2012—a compressed, but in this case feasible, timetable for recruitment.

Though the coalition needs more members, it doesn’t need all countries to join. A group of countries accounting for over 80% of these emissions—in the range of 15-25 members—would at least make it possible for the Coalition to have a major impact, though members would then need to adopt ambitious and effective policies. This is convenient, as it is easier to assemble a small number of countries that have common or complementary incentives to act (a “coalition of the willing”), than it is to find common ground among a large number of parties with widely disparate interests. Again, compare the UNFCCC, with universal (governmental) membership. The UNFCCC must engage all of the world’s countries, regardless of how little impact they have on climate change, how little stake they may have in its alleviation, or how variegated their interests might be, resulting in a long, slow slog toward a new international climate agreement in the UNFCCC. (And note that HFCs and methane are covered by the Kyoto Protocol, which Coalition members apparently feel is not doing enough to reduce their emissions.)

The Coalition is starting small and can grow relatively easily. That’s better than starting big (membership-wise) and being stuck there.

The Coalition’s strategy is smart in another way—by not focusing solely on climate change. Taking action to reduce greenhouse-gas emissions is a hard sell everywhere these days, and sweetening the pot with co-benefits helps. In the case of the Coalition, reducing black-carbon emissions will also have significant health co-benefits. (The Coalition addresses climate change and aims for “Clean Air.”) These magnify the interest of current and potential members and stakeholders—primarily developing-country governments (including three Coalition members) and NGOs advocating for poor families in developing countries, where many suffer from respiratory diseases caused by soot from poorly-designed indoor cookstoves and from outdoor sources. (The Global Alliance for Clean Cookstoves is collaborating with the Coalition.)

As Secretary Clinton and her Coalition partners readily admit, the world has to reduce CO2 emissions very significantly to prevent major climate damages—even if ancillary efforts such as the Coalition are successful. Ideally, those crafting climate agreements should aim for enough participants—but not too many—making binding commitments to actions that are ambitious and effective enough to solve the problem of climate change, over some time period that is reasonable, given the nature of the threat and the economic costs of the effort. Neither the Kyoto Protocol, the Coalition, nor other alternatives approach this ideal. However, well-designed institutional experiments are valuable in determining how to do so—and we must accept that some experiments will fail. Kudos to the founding members of the Coalition for trying something new.