President Obama shakes hands with Microsoft founder Bill Gates while French President Francois Hollande shakes hands with Indian Prime Minister Narendra Modi at the United Nations Climate Change Conference. (Ian Langsdon, Pool photo via AP)

This week, tens of thousands of climate activists, negotiators and policy wonks are in Paris to finalize the next phase of international climate policy. Many doubt that an agreement can be reached, or that any plausible agreement will make any meaningful progress on the increasingly real problem of climate change. It is extremely unlikely that Paris will be either a resounding success or an abysmal failure. More likely, it will serve as a useful next step toward a more ambitious set of both national and international policies to reduce greenhouse gas emissions.

To understand what the Paris meeting really means (technically, it’s the 21st Conference of the Parties to the UN Framework Convention on Climate Change), it’s useful to see how the pendulum has swung between two poles of conventional wisdom about what kind of global solutions are needed.

Climate change is a collective action problem

The received wisdom in social science is that global problems like climate change require an international treaty. Unless every country commits to reducing emissions, no one will. A single country reducing its emissions will bear all of the costs, while all countries reap the benefits of fewer emissions. This “free rider” problem is epitomized by Garrett Hardin’s “Tragedy of the Commons,” in which farmers must collectively agree to reduce the number of cattle they graze on a common pasture to avoid overgrazing. The farmers are collectively better off if they agree to reduce grazing but individually, it is most rational for each farmer to be selfish and graze as many of his or her own cattle as possible.

The same is true of climate change. As a planet, we are clearly better off avoiding climate change, and the accompanying effects: drought, sea-level rise, ocean acidification, just to name a few. Yet no nation wants to shoulder the burden of reductions unless everyone else does, and maybe not even then.

Enter the Kyoto Protocol. The Kyoto Protocol was a legally binding treaty aimed at solving the free rider problem by getting all major emitters to reduce. (Importantly, at the time the protocol was agreed, major emitters were all in the developing world. Developing countries had no obligations to reduce emissions under the Kyoto Protocol. This turned out to be a major sticking point.) Each country had a target — to reduce a given percentage below 1990 levels by 2012. The European Union had the most ambitious target: – 8 percent. Iceland had the least: it was allowed to increase its reductions by 10 percent.

As we now know, this approach didn’t work. In theory, it would have solved the free rider problem. But in practice, it didn’t account for one small issue: domestic politics.

Domestic politics is complicated

The biggest reason why the Kyoto protocol didn’t work was that it didn’t take into account domestic politics.  Countries such as the United States, and eventually Canada and Australia, did not appreciate how difficult it would be to sell the “one-size fits all” approach to their public.

The international community is now so wary of “top down” approaches like Kyoto that the pendulum has swung fully to the other end. In Paris, countries will agree to reduce greenhouse emissions in the way and at the level that they see fit. In climate speak, these “Intended Nationally Determined Contributions” (INDCs), allow each country to craft its own policy, in accordance with the preferences of its electorate.

From a political science perspective, this new bottom up approach has a few advantages. Although there is still some debate about the legal form of any Paris agreement, it’s pretty clear that it will not be a legally binding treaty like Kyoto. This lessens, if not eliminates, the role of enforcement. Such an approach is useful on a few fronts. Once countries sign a treaty, it must be ratified domestically in order to take legal effect. In many countries, this is politically difficult. In the United States, ratification involves approval of two-thirds of the Senate, a body that is not particularly keen on entering into treaties. There are currently 38 treaties awaiting ratification, one dating as far back as 1949. Moreover, enforcement is notoriously difficult in world politics. Generally speaking, we don’t invade countries for not complying with international treaties. And beyond force, there are very few other tools available.

A second advantage of the new approach is that there is no longer a distinction between the obligations that developed and developing countries have to reduce emissions. Kyoto divided the world into these two categories, and only required developed countries to reduce their emissions. Although this was politically important, it violated the main tenet of solving the free-rider problem, since more than half the world got to opt out. Now, every country is encouraged to do its share, though each gets to define what precisely that means. The hope is that a more flexible agreement will also allow countries to ratchet up their efforts over time.

Finally, the INDCs are public. You can read them online. The publicity of the new pledge and review approach suggests that shaming will be a tactic for keeping states on track.

Any deal will be insufficient on its own

The main drawback to the deal that will be struck in Paris is that it will not be nearly ambitious enough. Even accounting for the periodic ‘El Niño’ variation, 2015 is the hottest year on record. The current atmospheric concentration of carbon dioxide is approaching 400 parts per million — well past the target 350 ppm that most believe would keep warming to 2 degrees Celsius (3.6 degrees Fahrenheit). Paris may be a step in the right direction, but it’s debatable whether it’s a big enough step given the timeframe.

Finally, it’s important to note that no matter what happens in Paris, there is, and will continue to be a lot of positive activity on climate change. California, the world’s seventh largest economy, is now home to a carbon trading scheme. Prices are low (currently around $13 a ton), but California is not waiting for a federal policy to start acting. Beginning this year, its cap-and-trade program covers electricity generation, large stationary sources like refineries, and now fuel distributors. All told, 85 percent of California’s emissions come under the cap. What’s more, efforts like this create an institutional framework and rules, creating an obvious policy space for others to join in.

Another example is CDP, an international NGO, which collects data annually on the climate performance of over 5000 companies worldwide, representing 55 percent of the market capitalization of listed companies globally. While reporting emissions is not the same as reducing them, the data from CDP show a clear normative shift: Companies care more about climate change than ever before. Cognizant of how it could affect their bottom line, they are taking steps to address the problem, even without international regulations.

These sub-national and non-governmental efforts have a lot going for them. They’re not constrained by national politics. They have a lot of flexibility in deciding what types of initiatives they want to develop and who should be involved. And, they have more freedom to innovate than diplomats constrained by international negotiations. The big question is the same as the INDC approach: is it enough?

Jessica Green is an assistant professor of environmental studies at New York University.