Thursday, April 08, 2010
Krugman on Climate Change
Environmental Econ 101
If there’s a single central insight in economics, it’s this: There are mutual gains from transactions between consenting adults. If the going price of widgets is $10 and I buy a widget, it must be because that widget is worth more than $10 to me. If you sell a widget at that price, it must be because it costs you less than $10 to make it. So buying and selling in the widget market works to the benefit of both buyers and sellers. More than that, some careful analysis shows that if there is effective competition in the widget market, so that the price ends up matching the number of widgets people want to buy to the number of widgets other people want to sell, the outcome is to maximize the total gains to producers and consumers. Free markets are “efficient” — which, in economics-speak as opposed to plain English, means that nobody can be made better off without making someone else worse off.
Now, efficiency isn’t everything. In particular, there is no reason to assume that free markets will deliver an outcome that we consider fair or just. So the case for market efficiency says nothing about whether we should have, say, some form of guaranteed health insurance, aid to the poor and so forth. But the logic of basic economics says that we should try to achieve social goals through “aftermarket” interventions. That is, we should let markets do their job, making efficient use of the nation’s resources, then utilize taxes and transfers to help those whom the market passes by.
But what if a deal between consenting adults imposes costs on people who are not part of the exchange? What if you manufacture a widget and I buy it, to our mutual benefit, but the process of producing that widget involves dumping toxic sludge into other people’s drinking water? When there are “negative externalities” — costs that economic actors impose on others without paying a price for their actions — any presumption that the market economy, left to its own devices, will do the right thing goes out the window. So what should we do? Environmental economics is all about answering that question.
One way to deal with negative externalities is to make rules that prohibit or at least limit behavior that imposes especially high costs on others. That’s what we did in the first major wave of environmental legislation in the early 1970s: cars were required to meet emission standards for the chemicals that cause smog, factories were required to limit the volume of effluent they dumped into waterways and so on. And this approach yielded results; America’s air and water became a lot cleaner in the decades that followed.
But while the direct regulation of activities that cause pollution makes sense in some cases, it is seriously defective in others, because it does not offer any scope for flexibility and creativity. Consider the biggest environmental issue of the 1980s — acid rain. Emissions of sulfur dioxide from power plants, it turned out, tend to combine with water downwind and produce flora- and wildlife-destroying sulfuric acid. In 1977, the government made its first stab at confronting the issue, recommending that all new coal-fired plants have scrubbers to remove sulfur dioxide from their emissions. Imposing a tough standard on all plants was problematic, because retrofitting some older plants would have been extremely expensive. By regulating only new plants, however, the government passed up the opportunity to achieve fairly cheap pollution control at plants that were, in fact, easy to retrofit. Short of a de facto federal takeover of the power industry, with federal officials issuing specific instructions to each plant, how was this conundrum to be resolved?
Enter Arthur Cecil Pigou, an early-20th-century British don, whose 1920 book, “The Economics of Welfare,” is generally regarded as the ur-text of environmental economics.
Somewhat surprisingly, given his current status as a godfather of economically sophisticated environmentalism, Pigou didn’t actually stress the problem of pollution. Rather than focusing on, say, London’s famous fog (actually acrid smog, caused by millions of coal fires), he opened his discussion with an example that must have seemed twee even in 1920, a hypothetical case in which “the game-preserving activities of one occupier involve the overrunning of a neighboring occupier’s land by rabbits.” But never mind. What Pigou enunciated was a principle: economic activities that impose unrequited costs on other people should not always be banned, but they should be discouraged. And the right way to curb an activity, in most cases, is to put a price on it. So Pigou proposed that people who generate negative externalities should have to pay a fee reflecting the costs they impose on others — what has come to be known as a Pigovian tax. The simplest version of a Pigovian tax is an effluent fee: anyone who dumps pollutants into a river, or emits them into the air, must pay a sum proportional to the amount dumped.
Pigou’s analysis lay mostly fallow for almost half a century, as economists spent their time grappling with issues that seemed more pressing, like the Great Depression. But with the rise of environmental regulation, economists dusted off Pigou and began pressing for a “market-based” approach that gives the private sector an incentive, via prices, to limit pollution, as opposed to a “command and control” fix that issues specific instructions in the form of regulations.
The initial reaction by many environmental activists to this idea was hostile, largely on moral grounds. Pollution, they felt, should be treated like a crime rather than something you have the right to do as long as you pay enough money. Moral concerns aside, there was also considerable skepticism about whether market incentives would actually be successful in reducing pollution. Even today, Pigovian taxes as originally envisaged are relatively rare. The most successful example I’ve been able to find is a Dutch tax on discharges of water containing organic materials.
What has caught on instead is a variant that most economists consider more or less equivalent: a system of tradable emissions permits, a k a cap and trade. In this model, a limited number of licenses to emit a specified pollutant, like sulfur dioxide, are issued. A business that wants to create more pollution than it is licensed for can go out and buy additional licenses from other parties; a firm that has more licenses than it intends to use can sell its surplus. This gives everyone an incentive to reduce pollution, because buyers would not have to acquire as many licenses if they can cut back on their emissions, and sellers can unload more licenses if they do the same. In fact, economically, a cap-and-trade system produces the same incentives to reduce pollution as a Pigovian tax, with the price of licenses effectively serving as a tax on pollution.
In practice there are a couple of important differences between cap and trade and a pollution tax. One is that the two systems produce different types of uncertainty. If the government imposes a pollution tax, polluters know what price they will have to pay, but the government does not know how much pollution they will generate. If the government imposes a cap, it knows the amount of pollution, but polluters do not know what the price of emissions will be. Another important difference has to do with government revenue. A pollution tax is, well, a tax, which imposes costs on the private sector while generating revenue for the government. Cap and trade is a bit more complicated. If the government simply auctions off licenses and collects the revenue, then it is just like a tax. Cap and trade, however, often involves handing out licenses to existing players, so the potential revenue goes to industry instead of the government.
Politically speaking, doling out licenses to industry isn’t entirely bad, because it offers a way to partly compensate some of the groups whose interests would suffer if a serious climate-change policy were adopted. This can make passing legislation more feasible.
These political considerations probably explain why the solution to the acid-rain predicament took the form of cap and trade and why licenses to pollute were distributed free to power companies. It’s also worth noting that the Waxman-Markey bill, a cap-and-trade setup for greenhouse gases that starts by giving out many licenses to industry but puts up a growing number for auction in later years, was actually passed by the House of Representatives last year; it’s hard to imagine a broad-based emissions tax doing the same for many years.
That’s not to say that emission taxes are a complete nonstarter. Some senators have recently floated a proposal for a sort of hybrid solution, with cap and trade for some parts of the economy and carbon taxes for others — mainly oil and gas. The political logic seems to be that the oil industry thinks consumers won’t blame it for higher gas prices if those prices reflect an explicit tax.
In any case, experience suggests that market-based emission controls work. Our recent history with acid rain shows as much. The Clean Air Act of 1990 introduced a cap-and-trade system in which power plants could buy and sell the right to emit sulfur dioxide, leaving it up to individual companies to manage their own business within the new limits. Sure enough, over time sulfur-dioxide emissions from power plants were cut almost in half, at a much lower cost than even optimists expected; electricity prices fell instead of rising. Acid rain did not disappear as a problem, but it was significantly mitigated. The results, it would seem, demonstrated that we can deal with environmental problems when we have to.
So there we have it, right? The emission of carbon dioxide and other greenhouse gases is a classic negative externality — the “biggest market failure the world has ever seen,” in the words of Nicholas Stern, the author of a report on the subject for the British government. Textbook economics and real-world experience tell us that we should have policies to discourage activities that generate negative externalities and that it is generally best to rely on a market-based approach.
Subscribe to Post Comments [Atom]
Subscribe to Posts [Atom]