Taxing Carbon

While many observers were focused on the most obvious first represented by yesterday's presidential inauguration, I was thinking about another one: Barack Obama is the first US President elected on a platform that included putting a price on our emissions of carbon dioxide and other greenhouse gases to the atmosphere. Although the likelihood of that happening this year has receded somewhat, due to the weak economy, it would be just as momentous in a year or two. Either way, it's not a long interval in which to decide the best way to go about altering a practice that humanity has taken for granted since the discovery of fire. There are some very strong views on each side of the carbon tax vs. cap & trade dilemma.

Last week, the CEO of ExxonMobil made news when he came out in favor of a carbon tax, though in fairness, while Mr. Tillerson's remarks at the Woodrow Wilson Center in Washington, DC reflected a clear preference for a carbon tax over cap & trade, they fell short of advocating the immediate implementation of either. But however one chooses to parse his comments, the concerns he raised about cap and trade are entirely legitimate and must be addressed forthrightly in the political debate on limiting emissions of greenhouse gases (GHGs). One concern in particular seems likely to carry much more weight now than it would have a year or two ago:

"It is important to remember that a cap-and-trade system requires a new market infrastructure for traders to trade emissions allowances. This new 'Wall Street' of emissions brokers will take the emphasis away from the goal of reducing carbon emissions and focus its attention on trading on price volatility. For businesses and consumers, these market gatekeepers and resultant price swings add cost and they create uncertainty."

The idea of setting up a new market that will benefit traders and speculators is bound to raise some hackles, when these are widely viewed as having contributed to last summer's oil-price spike and to the larger financial crisis. If it weren't for one crucial shortcoming of a carbon tax, I would find Mr. Tillerson's arguments for its simplicity and predictability quite compelling, and the other justifications for cap & trade might be reduced to mere quibbles. To see why, let's consider the practical aspects of implementing either approach.

The ultimate goal of either cap & trade or a carbon tax is to reduce GHG emissions, in order to limit the extent of global warming and consequent changes in the earth's environment. These cuts are intended to begin gradually but quickly gather momentum to deliver substantial cumulative reductions in emissions within a few decades. Both cap & trade and a carbon tax would lend themselves to being carefully phased in, and either one could be rendered revenue-neutral, to minimize the undesired economic effects of a policy designed to alter our consumption patterns in fundamental ways, at least with regard to energy-intensive goods and services. In either system, vulnerable consumers and industries with few alternatives could be protected or given more time to adapt. And while cap & trade creates a strong incentive for companies and sectors with the lowest costs for reducing emissions to maximize their cuts and trade the resulting surplus with others who face higher costs, a carbon tax could be modified to allow some trading around the edges, capturing at least part of that benefit for the economy. The biggest distinction may also be the most basic: how is the price of emissions set in the first place?

In effect, the choice between a carbon tax and cap & trade boils down to a choice between the cost of CO2 being set by committee, or by markets. Whatever else disappointed investors might think about them, markets excel at price discovery. While I have little doubt that a blue-ribbon panel of economists, scientists and engineers could come up with a reasonable estimate of the level of carbon taxation required to reduce emissions by the desired amount, I have much more confidence in the logic of setting the desired level of emissions reduction in each year, and then allowing the price to emerge from the interaction of those whose livelihoods depend on meeting these limits, in real time. That preference is rooted in the risks of each approach.

If our hypothetical Carbon Price Committee sets the carbon tax too low, emissions will exceed the goal and they can ratchet the tax higher in the next period. However, if they set it too high, we'll beat the emissions targets, but the economy will shift too rapidly, and jobs and output in energy-intensive sectors will be shed faster than new, "green" jobs and products can be created. The result might look a lot like what we're experiencing today. Cap & trade has its own risks, though they tend to focus more on the effectiveness and efficiency of the program than on its consequences for the economy. Mr. Tillerson is right to identify problems of "verification and accountability," though there is already a large and growing body of experience in managing these issues, from the EU Emissions Trading System and from voluntary emissions trading--and the statutory SOx and NOx trading--that has been going on in the US for more than a decade.

In the final analysis, the decision to put a price on greenhouse gas emissions matters more than how it is implemented. At the same time, the latter choice will determine how effectively those reductions are achieved, and at what cost to the rest of the economy, where most of us will continue to earn our livelihoods and save for our future needs. I hope that the new administration will weigh these considerations carefully, in consultation with the Congress and all affected stakeholders, including our international trading partners, who could be affected in many ways by the result. The idea of a carbon tax deserves a fair hearing alongside cap & trade, once our leaders agree on the timing of limiting our emissions.