Via Cursor.org today, we get this alarming headline: "Arctic Ocean Could Be Ice-Free in Summer Within 100 Years, Scientists Say." Oh boy, wonder if the slowing of the Gulf Stream and the Siberia-ization of Europe can be far behind. On the scale of people who worry—or not—about global warming, I'm probably on the alarmist side; as in, I suspect very bad things will happen and no one seems to care enough to stop it. In order to stabilize atmospheric carbon concentrations at around 550 ppm by mid-century—the probable "redline" to avoid the most disastrous climate change scenarios—the world will need to get about 20-28 terawatts of energy from carbon-free sources by 2050, which is more energy than produced by all sources globally at present. (See Nathan Lewis' presentation here.) I've been doing a tiny bit of reporting on this lately and it's all very complicated, but suffice to say, I don't think that goal looks very feasible.

But set that aside; what I want to discuss right now is the Kyoto Protocol. Had the United States signed Kyoto way back in the day—which was never going to happen—we would have had to cut emissions about 25 to 30 percent below projected levels between 1997 and 2012. Obviously we'll never reach that goal now. When Bush effectively killed U.S. support for Kyoto in 2001, the common line among many Democrats was, "Fine, Kyoto sucks, but let's propose something else," and left it at that. No one, as far as I've heard, has proposed an alternative. Perhaps there's a reason for that. The flaws in Kyoto are both systemic and severe, and really do speak to the near-impossibility of being able to design anything better.

Ultimately, the Kyoto Protocol has a short time horizon, forcing countries to take a lot of effective and relatively cheap one-time measures to reduce emissions. Good stuff, but in this sense it's not a true long-term "plan" to avert catastrophic climate change. The design had a rationale to go with it; after all, the IPCC hasn't even reached a consensus on how much emissions should be allowed worldwide over, say, 100 years. Nor is there a consensus on what concentration of greenhouse gases is unacceptable. But ultimately, any alternative to Kyoto will need to take a long view: planning for, say, a rise in emissions over the next few decades followed by a steep drop; thus giving countries time to phase out old capital and invest in alternative energy sources (or to perfect carbon sequestration, or whatever). So that's hurdle one.

Second, any global emissions regime will always have to be voluntary in some sense, and this is a problem. How will countries be penalized if they fail to curtail emissions by X amount? The WTO, for instance, isn't a good model for enforcing a global emissions regime. Nobel laureate Thomas Schelling once proposed that we model any future Kyoto on NATO. During the early years of the Cold War, NATO members agreed among themselves to divvy up a fixed sum of money and make defense commitments; eventually they reached a voluntary agreement and stuck to it, even though there were no penalties for coming up short, and were able to harness the magic of comparative advantage to fulfill requirements without using any sort of "cap-and-trade" scheme.

But with NATO, each country agreed on what specific actions it would undertake, rather than a promise to produce X amount of "defense". (No one was saying that Europe needed to produce "60 units of deterrence by 1955," for instance.) That sounds silly, but it matters. With an emissions regime that focuses on getting to X level of emissions by Y date, it can be hard to monitor other countries year by year and make sure they're actually going to reach their targets—it might be impossible to know until the target date approaches. Especially since many countries may operate on different time frames—for instance, pursuing a strategy of letting emissions rise at first and then planning to decrease them later on. Moreover, countries may not even know how to reach a given target, and without specific guidance—say, Western Europe telling Eastern Europe, "You must fit these factories with X, Y, and Z; here's the technology"—it's not clear that focusing on results rather than actions will actually produce the results.

Perhaps a carbon tax could help. Economists prefer cap-and-trade regimes, whereby countries buy and sell credits for the "rights to pollute," so that nations that can reduce emissions most cost-effectively will do so first. This wouldn't solve the enforcement and timeframe problems listed above, however, and cap-and-trade schemes have their own flaws. First, the member countries are continually re-negotiating how many credits they get for a given time period. Some governments, then, may try to hold onto their excess credits so that they're treated more leniently in the next round of negotiations. Also, certain countries may be given excess credits in order to bribe them to stay in the program—this was the case with Russia in 2001. (Note that if implemented properly, cap-and-trade regimes can work very well within a country, where they can be enforced properly, although one might still expect "bribery" to take place.)

Ultimately, I think the way forward is for developed nations to invest, massively, in research and support for carbon-free energy sources around the world, as well as for alternative measures like carbon sequestration. Call it foreign aid. Call it socialism. Whatever. Abstractly, it might be preferable simply to impose limits on carbon emissions and then let the free market come up with whatever way it thinks best to meet those limits. Indeed, some combination of limits on emissions and investment seem ideal. But the actual difficulties in imposing something like the Kyoto Protocol look very severe to me, and it's not clear that it can be done in a fully effective manner. On the other hand, my preferred approach involves billions of dollars worth of taxpayer dollars from the United States, Japan, and Europe, to help save regions that—to be cold-blooded about it—will be able to deal with severe climate change more effectively than, say, Bangladesh or China. (Although everyone, obviously, will suffer.) So you can see why a little pessimism is in order.