Emissions trading, or cap and trade, is a market-based approach to controlling pollution by providing economic incentives for achieving reductions in the emissions of pollutants. In contrast to command-and-control environmental regulations such as best available technology (BAT) standards and government subsidies, cap and trade (CAT) schemes are a type of flexible environmental regulation that allows organizations to decide how best to meet policy targets. Various countries, states and groups of companies have adopted such trading systems, notably for mitigating climate change.
A central authority (usually a governmental body) allocates or sells a limited number of permits to discharge specific quantities of a specific pollutant per time period. Polluters are required to hold permits in amount equal to their emissions. Polluters that want to increase their emissions must buy permits from others willing to sell them. Financial derivatives of permits can also be traded on secondary markets.
In theory, polluters who can reduce emissions most cheaply will do so, achieving the emission reduction at the lowest cost to society. Cap and trade is meant to provide the private sector with the flexibility required to reduce emissions while stimulating technological innovation and economic growth.
There are active trading programs in several air pollutants. For greenhouse gases, which cause climate change, permit units are often called carbon credits. The largest greenhouse gases trading program is the European Union Emission Trading Scheme, which trades primarily in European Union Allowances (EUAs); the Californian scheme trades in California Carbon Allowances, the New Zealand scheme in New Zealand Units and the Australian scheme in Australian Units. The United States has a national market to reduce acid rain and several regional markets in nitrogen oxides.
Overview
Pollution is the prime example of a market externality. An externality is an effect of some activity on an entity (such as a person) that is not party to a market transaction related to that activity. Emissions trading is a market-based approach to address pollution. The overall goal of an emissions trading plan is to minimize the cost of meeting a set emissions target.
In an emissions trading system, the government sets an overall limit on emissions, and defines permits (also called allowances), or limited authorizations to emit, up to the level of the overall limit. The government may sell the permits, but in many existing schemes, it gives permits to participants (regulated polluters) equal to each participant’s baseline emissions. The baseline is determined by reference to the participant’s historical emissions. To demonstrate compliance, a participant must hold permits at least equal to the quantity of pollution it actually emitted during the time period. If every participant complies, the total pollution emitted will be at most equal to the sum of individual limits. Because permits can be bought and sold, a participant can choose either to use its permits exactly (by reducing its own emissions); or to emit less than its permits, and perhaps sell the excess permits; or to emit more than its permits, and buy permits from other participants. In effect, the buyer pays a charge for polluting, while the seller gains a reward for having reduced emissions.
In many schemes, organizations which do not pollute (and therefore have no obligations) may also trade permits and financial derivatives of permits. In some schemes, participants can bank allowances to use in future periods. In some schemes, a proportion of all traded permits must be retired periodically, causing a net reduction in emissions over time. Thus, environmental groups may buy and retire permits, driving up the price of the remaining permits according to the law of demand. In most schemes, permit owners can donate permits to a nonprofit entity and receive a tax deduction. Usually, the government lowers the overall limit over time, with an aim towards a national emissions reduction target.
According to the Environmental Defense Fund, cap-and-trade is the most environmentally and economically sensible approach to controlling greenhouse gas emissions, the primary cause of global warming, because it sets a limit on emissions, and the trading encourages companies to innovate in order to emit less.
“International trade can offer a range of positive and negative incentives to promote international cooperation on climate change (robust evidence, medium agreement). Three issues are key to developing constructive relationships between international trade and climate agreements: how existing trade policies and rules can be modified to be more climate friendly; whether border adjustment measures (BAMs) or other trade measures can be effective in meeting the goals of international climate agreements; whether the UNFCCC, World Trade Organization (WTO), hybrid of the two, or a new institution is the best forum for a trade-and-climate architecture.”
Market and least-cost
Some economists have urged the use of market-based instruments such as emissions trading to address environmental problems instead of prescriptive “command-and-control” regulation. Command and control regulation is criticized for being insensitive to geographical and technological differences, and therefore inefficient.; however, this is not always so, as shown by the WW-II rationing program in the U.S. in which local and regional boards made adjustments for these differences.
After an emissions limit has been set by a government political process, individual companies are free to choose how or whether to reduce their emissions. Failure to report emissions and surrender emission permits is often punishable by a further government regulatory mechanism, such as a fine that increases costs of production. Firms will choose the least-cost way to comply with the pollution regulation, which will lead to reductions where the least expensive solutions exist, while allowing emissions that are more expensive to reduce.
Under an emissions trading system, each regulated polluter has flexibility to use the most cost-effective combination of buying or selling emission permits, reducing its emissions by installing cleaner technology, or reducing its emissions by reducing production. The most cost-effective strategy depends on the polluter’s marginal abatement cost and the market price of permits. In theory, a polluter’s decisions should lead to an economically efficient allocation of reductions among polluters, and lower compliance costs for individual firms and for the economy overall, compared to command-and-control mechanisms.
Emission markets
For emissions trading where greenhouse gases are regulated, one emissions permit is considered equivalent to one metric ton of carbon dioxide (CO2) emissions. Other names for emissions permits are carbon credits, Kyoto units, assigned amount units, and Certified Emission Reduction units (CER). These permits can be sold privately or in the international market at the prevailing market price. These trade and settle internationally, and hence allow permits to be transferred between countries. Each international transfer is validated by the United Nations Framework Convention on Climate Change (UNFCCC). Each transfer of ownership within the European Union is additionally validated by the European Commission.
Emissions trading programmes such as the European Union Emissions Trading System (EU ETS) complement the country-to-country trading stipulated in the Kyoto Protocol by allowing private trading of permits. Under such programmes – which are generally co-ordinated with the national emissions targets provided within the framework of the Kyoto Protocol – a national or international authority allocates permits to individual companies based on established criteria, with a view to meeting national and/or regional Kyoto targets at the lowest overall economic cost.
Trading exchanges have been established to provide a spot market in permits, as well as futures and options market to help discover a market price and maintain liquidity. Carbon prices are normally quoted in euros per tonne of carbon dioxide or its equivalent (CO2e). Other greenhouse gases can also be traded, but are quoted as standard multiples of carbon dioxide with respect to their global warming potential. These features reduce the quota’s financial impact on business, while ensuring that the quotas are met at a national and international level.
Currently, there are six exchanges trading in UNFCCC related carbon credits: the Chicago Climate Exchange (until 2010), European Climate Exchange, NASDAQ OMX Commodities Europe, PowerNext, Commodity Exchange Bratislava and the European Energy Exchange. NASDAQ OMX Commodities Europe listed a contract to trade offsets generated by a CDM carbon project called Certified Emission Reductions. Many companies now engage in emissions abatement, offsetting, and sequestration programs to generate credits that can be sold on one of the exchanges. At least one private electronic market has been established in 2008: CantorCO2e. Carbon credits at Commodity Exchange Bratislava are traded at special platform called Carbon place.
Trading in emission permits is one of the fastest-growing segments in financial services in the City of London with a market estimated to be worth about €30 billion in 2007. Louis Redshaw, head of environmental markets at Barclays Capital, predicts that “carbon will be the world’s biggest commodity market, and it could become the world’s biggest market overall.”
Pollution markets
An emission license directly confers a right to emit pollutants up to a certain rate. In contrast, a pollution license for a given location confers the right to emit pollutants at a rate which will cause no more than a specified increase at the pollution-level. For concreteness, consider the following model.
There are agents each of which emits pollutants.
There are locations each of which suffers pollution .
The pollution is a linear combination of the emissions. The relation between is given by a diffusion matrix , such that: .
agents each of which emits 
pollutants.
locations each of which suffers pollution 
.
is given by a diffusion matrix 
.As an example, consider three countries along a river (as in the fair river sharing setting).
Pollution in the upstream country is determined only by the emission of the upstream country: .
Pollution in the middle country is determined by its own emission and by the emission of country 1: .
Pollution in the downstream country is the sum of all emissions: .
.
.
.So the matrix 
Each pollution-license for location 
Montgomery shows that, while both markets lead to efficient license allocation, the market in pollution-licenses is more widely applicable than the market in emission-licenses.
Public opinion
In the United States, most polling shows large support for emissions trading (often referred to as cap-and-trade). This majority support can be seen in polls conducted by Washington Post/ABC News, Zogby International and Yale University. A new Washington Post-ABC poll reveals that majorities of the American people believe in climate change, are concerned about it, are willing to change their lifestyles and pay more to address it, and want the federal government to regulate greenhouse gases. They are, however, ambivalent on cap-and-trade.
More than three-quarters of respondents, 77.0%, reported they “strongly support” (51.0%) or “somewhat support” (26.0%) the EPA’s decision to regulate carbon emissions. While 68.6% of respondents reported being “very willing” (23.0%) or “somewhat willing” (45.6%), another 26.8% reported being “somewhat unwilling” (8.8%) or “not at all willing” (18.0%) to pay higher prices for “Green” energy sources to support funding for programs that reduce the effect of global warming.
According to PolitiFact, it is a misconception that emissions trading is unpopular in the United States because of earlier polls from Zogby International and Rasmussen which misleadingly include “new taxes” in the questions (taxes aren’t part of emissions trading) or high energy cost estimates.
Comparison with other methods of emission reduction
Cap and trade is the textbook emissions trading program. Other market-based approaches include baseline-and-credit, and pollution tax. They all put a price on pollution (for example, see carbon price), and so provide an economic incentive to reduce pollution beginning with the lowest-cost opportunities. By contrast, in a command-and-control approach, a central authority designates pollution levels each facility is allowed to emit. Cap and trade essentially functions as a tax where the tax rate is variable based on the relative cost of abatement per unit, and the tax base is variable based on the amount of abatement needed.
Baseline and credit
In a baseline and credit program, polluters can create permits, called credits or offsets, by reducing their emissions below a baseline level, which is often the historical emissions level from a designated past year. Such credits can be bought by polluters that have a regulatory limit.
Pollution tax
Emissions fees or environmental tax is a surcharge on the pollution created while producing goods and services. For example, a carbon tax is a tax on the carbon content of fossil fuels that aims to discourage their use and thereby reduce carbon dioxide emissions. The two approaches are overlapping sets of policy designs. Both can have a range of scopes, points of regulation, and price schedules. They can be fair or unfair, depending on how the revenue is used. Both have the effect of increasing the price of goods (such as fossil fuels) to consumers. A comprehensive, upstream, auctioned cap-and-trade system is very similar to a comprehensive, upstream carbon tax. Yet, many commentators sharply contrast the two approaches.
The main difference is what is defined and what derived. A tax is a price control, while cap-and-trade method acts is a quantity control instrument. That is, a tax is a unit price for pollution that is set by authorities, and the market determines the quantity emitted; in cap and trade, authorities determine the amount of pollution, and the market determines the price. This difference affects a number of criteria.
Responsiveness to inflation: Cap-and-trade has the advantage that it adjusts to inflation (changes to overall prices) automatically, while emissions fees must be changed by regulators.
Responsiveness to cost changes: It is not clear which approach is better. It is possible to combine the two into a safety valve price: a price set by regulators, at which polluters can buy additional permits beyond the cap.
Responsiveness to recessions: This point is closely related to responsiveness to cost changes, because recessions cause a drop in demand. Under cap and trade, the emissions cost automatically decreases, so a cap-and-trade scheme adds another automatic stabilizer to the economy – in effect, an automatic fiscal stimulus. However, a lower pollution price also results in reduced efforts to reduce pollution. If the government is able to stimulate the economy regardless of the cap-and-trade scheme, an excessively low price causes a missed opportunity to cut emissions faster than planned. Instead, it might be better to have a price floor (a tax). This is especially true when cutting pollution is urgent, as with greenhouse gas emissions. A price floor also provides certainty and stability for investment in emissions reductions: recent experience from the UK shows that nuclear power operators are reluctant to invest on “un-subsidised” terms unless there is a guaranteed price floor for carbon (which the EU emissions trading scheme does not presently provide).
Responsiveness to uncertainty: As with cost changes, in a world of uncertainty, it is not clear whether emissions fees or cap-and-trade systems are more efficient—it depends on how fast the marginal social benefits of reducing pollution fall with the amount of cleanup (e.g., whether inelastic or elastic marginal social benefit schedule).
Other: The magnitude of the tax will depend on how sensitive the supply of emissions is to the price. The permit price of cap-and-trade will depend on the pollutant market. A tax generates government revenue, but full-auctioned emissions permits can do the same. A similar upstream cap-and-trade system could be implemented. An upstream carbon tax might be the simplest to administer. Setting up a complex cap-and-trade arrangement that is comprehensive has high institutional needs.
Command-and-control regulation
Command and control is a system of regulation that prescribes emission limits and compliance methods for each facility or source. It is the traditional approach to reducing air pollution.
Command-and-control regulations are more rigid than incentive-based approaches such as pollution fees and cap and trade. An example of this is a performance standard which sets an emissions goal for each polluter that is fixed and, therefore, the burden of reducing pollution cannot be shifted to the firms that can achieve it more cheaply. As a result, performance standards are likely to be more costly overall. The additional costs would be passed to end consumers.
Economics of international emissions trading
It is possible for a country to reduce emissions using a Command-Control approach, such as regulation, direct and indirect taxes. The cost of that approach differs between countries because the Marginal Abatement Cost Curve (MAC) — the cost of eliminating an additional unit of pollution — differs by country. It might cost China $2 to eliminate a ton of CO2, but it would probably cost Norway or the U.S. much more. International emissions-trading markets were created precisely to exploit differing MACs.
Example
Emissions trading through Gains from Trade can be more beneficial for both the buyer and the seller than a simple emissions capping scheme.
Consider two European countries, such as Germany and Sweden. Each can either reduce all the required amount of emissions by itself or it can choose to buy or sell in the market.
Suppose Germany can abate its CO2 at a much cheaper cost than Sweden, i.e. MACS > MACG where the MAC curve of Sweden is steeper (higher slope) than that of Germany, and RReq is the total amount of emissions that need to be reduced by a country.
On the left side of the graph is the MAC curve for Germany. RReq is the amount of required reductions for Germany, but at RReq the MACG curve has not intersected the market emissions permit price of CO2 (market permit price = P = λ). Thus, given the market price of CO2 allowances, Germany has potential to profit if it abates more emissions than required.
On the right side is the MAC curve for Sweden. RReq is the amount of required reductions for Sweden, but the MACS curve already intersects the market price of CO2 permits before RReq has been reached. Thus, given the market price of CO2 permits, Sweden has potential to make a cost saving if it abates fewer emissions than required internally, and instead abates them elsewhere.
In this example, Sweden would abate emissions until its MACS intersects with P (at R*), but this would only reduce a fraction of Sweden’s total required abatement.
After that it could buy emissions credits from Germany for the price P (per unit). The internal cost of Sweden’s own abatement, combined with the permits it buys in the market from Germany, adds up to the total required reductions (RReq) for Sweden. Thus Sweden can make a saving from buying permits in the market (Δ d-e-f). This represents the “Gains from Trade”, the amount of additional expense that Sweden would otherwise have to spend if it abated all of its required emissions by itself without trading.
Germany made a profit on its additional emissions abatement, above what was required: it met the regulations by abating all of the emissions that was required of it (RReq). Additionally, Germany sold its surplus permits to Sweden, and was paid P for every unit it abated, while spending less than P. Its total revenue is the area of the graph (RReq 1 2 R*), its total abatement cost is area (RReq 3 2 R*), and so its net benefit from selling emission permits is the area (Δ 1-2-3) i.e. Gains from Trade
The two R* (on both graphs) represent the efficient allocations that arise from trading.
Germany: sold (R* – RReq) emission permits to Sweden at a unit price P.
Sweden bought emission permits from Germany at a unit price P.
If the total cost for reducing a particular amount of emissions in the Command Control scenario is called X, then to reduce the same amount of combined pollution in Sweden and Germany, the total abatement cost would be less in the Emissions Trading scenario i.e. (X — Δ 123 – Δ def).
The example above applies not just at the national level, but also between two companies in different countries, or between two subsidiaries within the same company.
Applying the economic theory
The nature of the pollutant plays a very important role when policy-makers decide which framework should be used to control pollution. CO2 acts globally, thus its impact on the environment is generally similar wherever in the globe it is released. So the location of the originator of the emissions does not matter from an environmental standpoint.
The policy framework should be different for regional pollutants (e.g. SO2 and NOx, and also mercury) because the impact of these pollutants may differ by location. The same amount of a regional pollutant can exert a very high impact in some locations and a low impact in other locations, so it matters where the pollutant is released. This is known as the Hot Spot problem.
A Lagrange framework is commonly used to determine the least cost of achieving an objective, in this case the total reduction in emissions required in a year. In some cases, it is possible to use the Lagrange optimization framework to determine the required reductions for each country (based on their MAC) so that the total cost of reduction is minimized. In such a scenario, the Lagrange multiplier represents the market allowance price (P) of a pollutant, such as the current market price of emission permits in Europe and the USA.
Countries face the permit market price that exists in the market that day, so they are able to make individual decisions that would minimize their costs while at the same time achieving regulatory compliance. This is also another version of the Equi-Marginal Principle, commonly used in economics to choose the most economically efficient decision.
Prices versus quantities, and the safety valve
There has been longstanding debate on the relative merits of price versus quantity instruments to achieve emission reductions.
An emission cap and permit trading system is a quantity instrument because it fixes the overall emission level (quantity) and allows the price to vary. Uncertainty in future supply and demand conditions (market volatility) coupled with a fixed number of pollution permits creates an uncertainty in the future price of pollution permits, and the industry must accordingly bear the cost of adapting to these volatile market conditions. The burden of a volatile market thus lies with the industry rather than the controlling agency, which is generally more efficient. However, under volatile market conditions, the ability of the controlling agency to alter the caps will translate into an ability to pick “winners and losers” and thus presents an opportunity for corruption.
In contrast, an emission tax is a price instrument because it fixes the price while the emission level is allowed to vary according to economic activity. A major drawback of an emission tax is that the environmental outcome (e.g. a limit on the amount of emissions) is not guaranteed. On one hand, a tax will remove capital from the industry, suppressing possibly useful economic activity, but conversely, the polluter will not need to hedge as much against future uncertainty since the amount of tax will track with profits. The burden of a volatile market will be borne by the controlling (taxing) agency rather than the industry itself, which is generally less efficient. An advantage is that, given a uniform tax rate and a volatile market, the taxing entity will not be in a position to pick “winners and losers” and the opportunity for corruption will be less.
Assuming no corruption and assuming that the controlling agency and the industry are equally efficient at adapting to volatile market conditions, the best choice depends on the sensitivity of the costs of emission reduction, compared to the sensitivity of the benefits (i.e., climate damage avoided by a reduction) when the level of emission control is varied.
Because there is high uncertainty in the compliance costs of firms, some argue that the optimum choice is the price mechanism. However, the burden of uncertainty cannot be eliminated, and in this case it is shifted to the taxing agency itself.
The overwhelming majority of climate scientists have repeatedly warned of a threshold in atmospheric concentrations of carbon dioxide beyond which a run-away warming effect could take place, with a large possibility of causing irreversible damage. With such a risk, a quantity instrument may be a better choice because the quantity of emissions may be capped with more certainty. However, this may not be true if this risk exists but cannot be attached to a known level of greenhouse gas (GHG) concentration or a known emission pathway.
A third option, known as a safety valve, is a hybrid of the price and quantity instruments. The system is essentially an emission cap and permit trading system but the maximum (or minimum) permit price is capped. Emitters have the choice of either obtaining permits in the marketplace or buying them from the government at a specified trigger price (which could be adjusted over time). The system is sometimes recommended as a way of overcoming the fundamental disadvantages of both systems by giving governments the flexibility to adjust the system as new information comes to light. It can be shown that by setting the trigger price high enough, or the number of permits low enough, the safety valve can be used to mimic either a pure quantity or pure price mechanism.
All three methods are being used as policy instruments to control greenhouse gas emissions: the EU-ETS is a quantity system using the cap and trading system to meet targets set by National Allocation Plans; Denmark has a price system using a carbon tax (World Bank, 2010, p. 218), while China uses the CO2 market price for funding of its Clean Development Mechanism projects, but imposes a safety valve of a minimum price per tonne of CO2.
Carbon leakage
Carbon leakage is the effect that regulation of emissions in one country/sector has on the emissions in other countries/sectors that are not subject to the same regulation. There is no consensus over the magnitude of long-term carbon leakage.
In the Kyoto Protocol, Annex I countries are subject to caps on emissions, but non-Annex I countries are not. Barker et al. (2007) assessed the literature on leakage. The leakage rate is defined as the increase in CO2 emissions outside the countries taking domestic mitigation action, divided by the reduction in emissions of countries taking domestic mitigation action. Accordingly, a leakage rate greater than 100% means that actions to reduce emissions within countries had the effect of increasing emissions in other countries to a greater extent, i.e., domestic mitigation action had actually led to an increase in global emissions.
Estimates of leakage rates for action under the Kyoto Protocol ranged from 5% to 20% as a result of a loss in price competitiveness, but these leakage rates were considered very uncertain. For energy-intensive industries, the beneficial effects of Annex I actions through technological development were considered possibly substantial. However, this beneficial effect had not been reliably quantified. On the empirical evidence they assessed, Barker et al. (2007) concluded that the competitive losses of then-current mitigation actions, e.g., the EU ETS, were not significant.
Under the EU ETS rules Carbon Leakage Exposure Factor is used to determine the volumes of free allocation of emission permits to industrial installations.
Trade
To understand carbon trading, it is important to understand the products that are being traded. The primary product in carbon markets is the trading of GHG emission permits. Under a cap-and-trade system, permits are issued to various entities for the right to emit GHG emissions that meet emission reduction requirement caps.
One of the controversies about carbon mitigation policy is how to “level the playing field” with border adjustments. For example, one component of the American Clean Energy and Security Act (a 2009 bill that did not pass), along with several other energy bills put before US Congress, calls for carbon surcharges on goods imported from countries without cap-and-trade programs. Besides issues of compliance with the General Agreement on Tariffs and Trade, such border adjustments presume that the producing countries bear responsibility for the carbon emissions.
A general perception among developing countries is that discussion of climate change in trade negotiations could lead to “green protectionism” by high-income countries (World Bank, 2010, p. 251). Tariffs on imports (“virtual carbon”) consistent with a carbon price of $50 per ton of CO2 could be significant for developing countries. World Bank (2010) commented that introducing border tariffs could lead to a proliferation of trade measures where the competitive playing field is viewed as being uneven. Tariffs could also be a burden on low-income countries that have contributed very little to the problem of climate change.
Source from Wikipedia