Climate change mitigation

Global carbon dioxide emissions from human activities 1800–2004

Global average surface temperature 1850 to 2007

Mitigation of global warming requires reducing the intensity of radiative forcing in order to reduce global warming. Mitigation is distinguished from adaptation, which involves acting to minimize the effects of global warming. Most often, mitigations involve reductions in the concentrations of greenhouse gases, either by reducing their sources or by increasing their sinks.

Means of mitigation

Scientific consensus on global warming, together with the precautionary principle and the fear of abrupt climate change is leading to increased effort to develop new technologies and sciences and carefully manage others in an attempt to mitigate global warming. Unfortunately most means of mitigation appear effective only for preventing further warming, not at reversing existing warming.

The Stern Review identifies several ways of mitigating climate change. These include reducing demand for emissions-intensive goods and services, increasing efficiency gains, increasing use and development of low-carbon technologies, and reducing non-fossil fuel emissions.

The energy policy of the European Union has set a target of limiting the global temperature rise to 2 °C [3.6 °F] compared to preindustrial levels, of which 0.8 °C has already taken place and another 0.5 °C is already committed. The 2 °C rise is typically associated in climate models with a carbon dioxide concentration of 400-500 ppm by volume; the current level as of January 2007 is 383 ppm by volume, and rising at 2 ppm annually. Hence, to avoid a very likely breach of the 2 °C target, CO₂ levels would have to be stabilised very soon; this is generally regarded as unlikely, based on current programs in place to date. The importance of change is illustrated by the fact that world economic energy efficiency is presently improving at only half the rate of world economic growth.

At the core of most proposals is the reduction of greenhouse gas emissions through reducing energy use and switching to cleaner energy sources. Frequently discussed energy conservation methods include increasing the fuel efficiency of vehicles (often through hybrid, plug-in hybrid, and electric cars and improving conventional automobiles), individual-lifestyle changes and changing business practices. Newly developed technologies and currently available technologies including renewable energy (such as solar power, tidal and ocean energy, geothermal power, and wind power) and more controversially nuclear power and the use of carbon sinks, carbon credits, and taxation are aimed more precisely at countering continued greenhouse gas emissions. More radical proposals which may be grouped with mitigation include biosequestration of atmospheric carbon dioxide and geoengineering techniques ranging from carbon sequestration projects such as carbon dioxide air capture, to solar radiation management schemes such as the creation of stratospheric sulfur aerosols. The ever-increasing global population and the planned growth of national GDPs based on current technologies are counter-productive to most of these proposals.

Quota on fossil fuel production

Most mitigation proposals imply - rather than directly state - an eventual reduction in global fossil fuel production. Also proposed are direct quotas on global fossil fuel production.

Pacala and Socolow

Pacala and Socolow of Princeton have proposed a program to reduce CO₂ emissions by 1 billion metric tons per year − or 25 billion tons over the 50-year period. The proposed 15 different programs, any seven of which could achieve the goal, are:

1. more efficient vehicles − increase fuel economy from 30 to 60 mpg (7.8 to 3.9 L/100 km) for 2 billion vehicles,
2. reduce use of vehicles − improve urban design to reduce miles driven from 10,000 to 5,000 miles (16,000 to 8,000 km) per year for 2 billion vehicles,
3. efficient buildings − reduce energy consumption by 25%,
4. improve efficiency of coal plants from today's 40% to 60%,
5. replace 1,400 GW (gigawatt) of coal power plants with natural gas,
6. capture and store carbon emitted from 800 GW of new coal plants,
7. capture and reuse hydrogen created by #6 above,
8. capture and store carbon from coal to syn fuels conversion at 30 million barrels per day (4,800,000 m³/d),
9. displace 700 GW of coal power with nuclear,
10. add 2 million 1 MW wind turbines (50 times current capacity),
11. displace 700 GW of coal with 2,000 GW (peak) solar power (700 times current capacity),
12. produce hydrogen fuel from 4 million 1 MW wind turbines,
13. use biomass to make fuel to displace oil (100 times current capacity),
14. stop de-forestation and re-establish 300 million hectares of new tree plantations,
15. conservation tillage − apply to all crop land (10 times current usage).

Nature.com argued in June 2008 that "If we are to have confidence in our ability to stabilize carbon dioxide levels below 450 p.p.m. emissions must average less than 5 billion metric tons of carbon per year over the century. This means accelerating the deployment of the wedges so they begin to take effect in 2015 and are completely operational in much less time than originally modelled by Socolow and Pacala."

Further information: Stabilization Wedge Game and Global warming game

Energy efficiency and conservation

Main articles: Energy efficiency and Energy conservation

Developing countries use their energy less efficiently than developed countries, getting less GDP for the same amount of energy.

The Energy Information Administration predicts world energy usage will rise in the next few decades.

Reducing fuel use by improvements in efficiency provides environmental benefits and as well as net cost savings to the energy user. Building insulation, fluorescent lighting, and public transportation are some of the most effective means of conserving energy, and by extension, the environment. However, Jevons paradox poses a challenge to the goal of reducing overall energy use (and thus environmental impact) by energy conservation methods. Improved efficiency lowers cost, which in turn increases demand. To ensure that increases in efficiency actually reduces energy use, a tax must be imposed to remove any cost savings from improved efficiency.

Energy conservation is the practice of increasing the efficiency of use of energy in order to achieve higher useful output for the same energy consumption. This may result in increase of national security, personal security, financial capital, human comfort and environmental value. Individuals and organizations that are direct consumers of energy may want to conserve energy in order to reduce energy costs and promote environmental values. Industrial and commercial users may want to increase efficiency and maximize profit.

On a larger scale, energy conservation is an element of energy policy. The need to increase the available supply of energy (for example, through the creation of new power plants, or by the importation of more energy) is lessened if societal demand for energy can be reduced, or if growth in demand can be slowed. This makes energy conservation an important part of the debate over climate change and the replacement of non-renewable resources with renewable energy. Encouraging energy conservation among consumers is often advocated as a cheaper or more environmentally sensitive alternative to increased energy production.

The energy landscape

Residential buildings, commercial buildings, and the transportation of people and freight use the majority of the energy consumed by the United States each year. Specifically, the industrial sector uses 38 percent of total energy, closely followed by the transportation sector at 28 percent, the residential sector at 19 percent, and the commercial sector at 16 percent. On a community level, transportation can account for 40 to 50 percent of total energy use, and residential buildings use another 20 to 30 percent.

In developed nations, the way of life today is completely dependent on abundant supplies of energy. Energy is needed to heat, cool, and light homes, fuel cars, and power offices. Energy is also critical for manufacturing the products used every day, including the cement, concrete and bricks that shape our communities.

While the U.S represents only five percent of the world's population, it consumes 25 percent of its energy and generates about 25 percent of its total greenhouse gas emissions. U.S. citizens, for example, use more energy per capita for transportation than do citizens of any other industrialized nation—which in part, reflects the greater distances traveled by Americans compared with citizens of other nations.

Urban planning

Main article: Urban planning

Urban planning also has an effect on energy use. Between 1982 and 1997, the amount of land consumed for urban development in the United States increased by 47 percent while the nation's population grew by only 17 percent. Inefficient land use development practices have increased infrastructure costs as well as the amount of energy needed for transportation, community services, and buildings.

At the same time, a growing number of citizens and government officials have begun advocating a smarter approach to land use planning. These smart growth practices include compact community development, multiple transportation choices, mixed land uses, and practices to conserve green space. These programs offer environmental, economic, and quality-of-life benefits; and they also serve to reduce energy usage and greenhouse gas emissions.

Approaches such as New Urbanism and Transit-oriented development seek to reduce distances travelled, especially by private vehicles, encourage public transit and make walking and cycling more attractive options. This is achieved through medium-density, mixed-use planning and the concentration of housing within walking distance of town centers and transport nodes.

Smarter growth land use policies have both a direct and indirect effect on energy consuming behavior. For example, transportation energy usage, the number one user of petroleum fuels, could be significantly reduced through more compact and mixed use land development patterns, which in turn could be served by a greater variety of non-automotive based transportation choices.

See also: Smart Growth

Building design

Main articles: Sustainable architecture and Green building

File:Bedzed.jpg

BedZED zero-energy housing in the UK

Emissions from housing are substantial, and government-supported energy efficiency programmes can make a difference.

New buildings can be constructed using passive solar building design, low-energy building, or zero-energy building techniques, using renewable heat sources. Existing buildings can be made more efficient through the use of insulation, high-efficiency appliances (particularly hot water heaters and furnaces), double- or triple-glazed gas-filled windows, external window shades, and building orientation and siting. Renewable heat sources such as shallow geothermal and passive solar energy reduce the amount of greenhouse gasses emitted. In addition to designing buildings which are more energy efficient to heat, it is possible to design buildings that are more energy efficient to cool by using lighter-coloured, more reflective materials in the development of urban areas (e.g. by painting roofs white) and planting trees. This saves energy because it cools buildings and reduces the urban heat island effect thus reducing the use of air conditioning.

Transport

Bicycles have almost no carbon footprint compared to cars.

Main article: Sustainable transport

Modern energy efficient technologies, such as plug-in hybrid electric vehicles, and development of new technologies, such as hydrogen cars, may reduce the consumption of petroleum and emissions of carbon dioxide.

A shift from air transport and truck transport to electric rail transport would reduce emissions significantly.

Increased use of biofuels (such as biodiesel and biobutanol, that can be used in 100% concentration in today's diesel and gasoline engines) could also reduce emissions if produced environmentally efficiently, especially in conjunction with regular hybrids and plug-in hybrids.

For electric vehicles, the reduction of carbon emissions will improve further if the way the required electricity is generated is low-carbon (from renewable energy sources).

Effective urban planning to reduce sprawl would decrease Vehicle Miles Travelled (VMT), lowering emissions from transportation. Increased use of public transport can also reduce greenhouse gas emissions per passenger kilometer.

Alternative energy sources

Main article: Energy development

Nuclear power

Cattenom Nuclear Power Plant.

Nuclear power currently produces over 15% of the world's electricity. Due to its low emittance of greenhouse gases (comparable to wind power) and reliability it is seen as a possible alternative to fossil fuels, but is controversial for reasons of capital cost and possible environmental impacts. Also, there are political impacts in some countries.

Life-cycle greenhouse gas emissions comparisons

Most comparisons of life cycle analysis (LCA) of carbon dioxide emissions show nuclear power as comparable to renewable energy sources.

A life cycle analysis centered around the Swedish Forsmark Nuclear Power Plant estimated carbon dioxide emissions at 3.10 g/kWh and 5.05 g/kWh in 2002 for the Torness Nuclear Power Station. This compares to 11 g/kWh for hydroelectric power, 950 g/kWh for installed coal, 900 g/kWh for oil and 600 g/kWh for natural gas generation in the United States in 1999.

The Vattenfall study found Nuclear, Hydro, and Wind to have far less greenhouse emissions than other sources represented.

The Swedish utility Vattenfall did a study of full life cycle emissions of nuclear, hydro, coal, gas, solar cell, peat and wind which the utility uses to produce electricity. The net result of the study was that nuclear power produced 3.3 grams of carbon dioxide per KW-Hr of produced power. This compares to 400 for natural gas and 700 for coal (according to this study). The study also concluded that nuclear power produced the smallest amount of CO₂ of any of their electricity sources.

Enrichment

The bulk of CO₂ emission from nuclear power plants can be eliminated if nuclear power plants themselves generate the electricity required during the uranium enrichment process (already being done in France and to some extent by the Tennessee Valley Authority's many nuclear units in the U.S.). In addition, gas centrifuge technology has/will greatly reduced the energy required for enrichment, thus reducing the LCA carbon emissions per kilowatt-hour (see Piketon plant).

Nuclear fuel reserves

Current uranium production is expected to be adequate at current consumption rates for about a century (from uranium mining, see also peak uranium).

There are a number of alternative nuclear fission technologies, such as breeder reactors, (see generation IV reactors) which could vastly extend fuel supplies if successfully developed and utilized.

Lower-risk thorium cycles have been demonstrated in the past.

Nuclear fusion is another variant of providing nuclear energy, but it will not provide any immediate mitigation to global warming as the time horizon for its commercial deployment is expected to be after 2050.

Renewable energy

This three-bladed wind turbine is the most common modern design because it minimizes forces related to fatigue.

Main articles: Renewable energy and Renewable energy development

One means of reducing carbon emissions is the development of new technologies such as renewable energy such as wind power. Most forms of renewable energy generate no appreciable amounts of greenhouse gases except for biofuels derived from biomass, as well as some biofuels derived from fossil fuel sources.

Helioculture is a newly developed process which is claimed to be able to produce 20,000 gallons of fuel per acre per year, and which removes carbon dioxide from the air as a feedstock for the fuel.

Generally, emissions are a fraction of fossil fuel-based electricity generation. In some cases, notably with hydroelectric dams--once thought to be one of the cleanest forms of energy—there are unexpected results. One study shows that a hydroelectric dam in the Amazon has 3.6 times larger greenhouse effect per kW·h than electricity production from oil, due to large scale emission of methane from decaying organic material. This effect applies in particular to dams created by simply flooding a large area, without first clearing it of vegetation. There are however investigations into underwater turbines that do not require a dam.

Currently governments subsidize fossil fuels by an estimated $235 billion a year. However, in some countries, government action has boosted the development of renewable energy technologies—for example, a program to put solar panels on the roofs of a million homes has made Japan a world leader in that technology, and Denmark's support for wind power ensured its former leadership of that sector. In 2005, Governor Arnold Schwarzenegger promised an initiative to install a million solar roofs in California, which became the California Solar Initiative.

In June 2005, the chief executive of BT allegedly became the first head of a British company to admit that climate change is already affecting his company, and affecting its business, and announced plans to source much of its substantial energy use from renewable sources. He noted that, "Since the beginning of the year, the media has been showing us images of Greenland glaciers crashing into the sea, Mount Kilimanjaro devoid of its ice cap and Scotland reeling from floods and gales. All down to natural weather cycles? I think not."

Eliminating waste methane

Methane is a significantly more powerful greenhouse gas than carbon dioxide. Burning one molecule of methane generates one molecule of carbon dioxide. Accordingly, burning methane which would otherwise be released into the atmosphere (such as at oil wells, landfills, coal mines, waste treatment plants, etc.) provides a net greenhouse gas emissions benefit. However, reducing the amount of waste methane produced in the first place has an even greater beneficial impact, as might other approaches to productive use of otherwise-wasted methane.

In terms of prevention, vaccines are in the works in Australia to reduce significant global warming contributions from methane released by livestock via flatulence and eructation.

Carbon intensity of fossil fuels

Natural gas (predominantly methane) produces less greenhouses gases per energy unit gained than oil which in turn produces less than coal, principally because coal has a larger ratio of carbon to hydrogen. The combustion of natural gas emits almost 30 percent less carbon dioxide than oil, and just under 45 percent less carbon dioxide than coal. In addition, there are also other environmental benefits.

A study performed by the Environmental Protection Agency (EPA) and the Gas Research Institute (GRI) in 1997 sought to discover whether the reduction in carbon dioxide emissions from increased natural gas (predominantly methane) use would be offset by a possible increased level of methane emissions from sources such as leaks and emissions. The study concluded that the reduction in emissions from increased natural gas use strongly outweighs the detrimental effects of increased methane emissions. Thus the increased use of natural gas in the place of other, dirtier fossil fuels can serve to lessen the emission of greenhouse gases in the United States.

Reforestation and avoided deforestation

Main articles: Deforestation, Reforestation, and Biosequestration

Almost 20% (8 GtCO₂/year) of total greenhouse-gas emissions were from deforestation in 2007. The Stern Review found that, based on the opportunity costs of the landuse that would no longer be available for agriculture if deforestation were avoided, emission savings from avoided deforestation could potentially reduce CO₂ emissions for under $5/tCO₂, possiblly as little as $1/tCO₂. Afforestation and reforestation could save at least another 1GtCO₂/year, at an estimated cost of $5/tCO₂ to $15/tCO₂. The Review determined these figures by assessing 8 countries responsible for 70% of global deforestation emissions.

Pristine temperate forest has been shown to store three times more carbon than IPCC estimates took into account, and 60% more carbon than plantation forest. Preventing these forests from being logged would have significant effects.

Further significant savings from other non-energy-related-emissions could be gained through cuts to agricultural emissions, fugitive emissions, waste emissions, and emissions from various industrial processes.

Carbon capture and storage

Schematic showing both terrestrial and geological sequestration of carbon dioxide emissions from a coal-fired plant.

Main article: Carbon capture and storage

See also: Bio-energy with carbon storage and Biochar

Carbon capture and storage (CCS) is a plan to mitigate climate change by capturing carbon dioxide (CO₂) from large point sources such as power plants and subsequently storing it away safely instead of releasing it into the atmosphere. Technology for capturing of CO₂ is already commercially available for large CO₂ emitters, such as power plants. Storage of CO₂, on the other hand is a relatively untried concept and as yet (2007) no powerplant operates with a full carbon capture and storage system. When this technique is used with biomass, the technique is known as biomass energy with carbon capture and storage and may be carbon negative.

CCS applied to a modern conventional power plant could reduce CO₂ emissions to the atmosphere by approximately 80-90% compared to a plant without CCS.

Storage of the CO₂ is envisaged either in deep geological formations, deep oceans, or in the form of mineral carbonates. Geological formations are currently considered the most promising, and these are estimated to have a storage capacity of at least 2000 Gt CO₂. IPCC estimates that the economic potential of CCS could be between 10% and 55% of the total carbon mitigation effort until year 2100.

In October 2007, the Bureau of Economic Geology at The University of Texas at Austin received a 10-year, $38 million subcontract to conduct the first intensively monitored, long-term project in the United States studying the feasibility of injecting a large volume of CO₂ for underground storage. The project is a research program of the Southeast Regional Carbon Sequestration Partnership (SECARB), funded by the National Energy Technology Laboratory of the U.S. Department of Energy (DOE). The SECARB partnership will demonstrate CO₂ injection rate and storage capacity in the Tuscaloosa-Woodbine geologic system that stretches from Texas to Florida. The region has the potential to store more than 200 billion tons of CO₂ from major point sources in the region, equal to about 33 years of U.S. emissions overall at present rates. Beginning in fall 2007, the project will inject CO₂ at the rate of one million tons per year, for up to 1.5 years, into brine up to 10,000 feet (3,000 m) below the land surface near the Cranfield oil field about 15 miles (24 km) east of Natchez, Mississippi. Experimental equipment will measure the ability of the subsurface to accept and retain CO₂.

Non-CO₂ climate actors

Action has been suggested on soot, HFCs and other climate drivers, in addition to that proposed for CO₂ . Emissions of some of these actors are considered by the Kyoto Protocol.

Geoengineering

Main article: geoengineering

Geoengineering is seen by some as an alternative to mitigation and adaptation, but by others as an entirely separate response to climate change. Carbon sequestration is a form of mitigation, but is not mitigation as defined by climate activists. To them, the term is clearly defined as exclusively associated with reduction of greenhouse gas emissions.

Chapter 28 of the National Academy of Sciences report Policy Implications of Greenhouse Warming: Mitigation, Adaptation, and the Science Base (1992) defined geoengineering as "options that would involve large-scale engineering of our environment in order to combat or counteract the effects of changes in atmospheric chemistry." They evaluated a range of options to try to give preliminary answers to two questions: can these options work and could they be carried out with a reasonable cost. They also sought to encourage discussion of a third question - what adverse side effects might there be. The following types of option were examined: reforestation, increasing ocean absorption of carbon dioxide (carbon sequestration) and screening out some sunlight. NAS also argued "Engineered countermeasures need to be evaluated but should not be implemented without broad understanding of the direct effects and the potential side effects, the ethical issues, and the risks.".

Solar radiation management

Jets have been suggested to deliver aerosol precursors to the stratosphere, although the feasibility of using them has not been evaluated

Main articles: Solar radiation management, Stratospheric sulfur aerosols (geoengineering), and Marine cloud brightening

Some scientists have suggested using aerosols and/or sulfate dust to alter the Earth's albedo, or reflectivity, as an emergency measure to increase global dimming and thus stave off the effects of global warming. A 0.5% albedo increase would roughly halve the effect of CO₂ doubling. In 1974, Russian expert Mikhail Budyko suggested that if global warming became a problem, we could cool down the planet by burning sulfur in the stratosphere, which would create a haze. Paul Crutzen suggests that this would cost 25 to 50 billion dollars/year. It would, however, increase the environmental problem of acid rain (although optimized engineering is thought to reduce this to insignificant levels)and drought.

An alternative technique, which may be more benign, is marine cloud brightening. Others have proposed building a literal solar shade in space.

Greenhouse gas remediation

Main articles: Greenhouse gas remediation and Carbon sequestration

Carbon sequestration has been proposed as a method of reducing the amount of radiative forcing. Carbon sequestration is a term that describes processes that remove carbon from the atmosphere. A variety of means of artificially capturing and storing carbon, as well as of enhancing natural sequestration processes, are being explored. The main natural process is photosynthesis by plants and single-celled organisms (see biosequestration). Artificial processes vary, and concerns have been expressed about their long-term effects.

Although they require land, natural sinks can be enhanced by reforestation and afforestation carbon offsets, which fix carbon dioxide for as little as $0.11 per metric ton.

Biochar

Main article: Biochar

Charcoal, or biochar, created by pyrolysis of biomass can be buried to create terra preta. The production of biochar may or may not involve energy recovery. The intention is that the carbon in the biomass is removed from the atmosphere for a longer period of time than would otherwise be the case.

Bio-energy with carbon capture and storage, BECCS

Main article: Bio-energy with carbon capture and storage

During its growth, biomass traps carbon dioxide from the atmosphere through photosynthesis. When the biomass decomposes or is combusted, the carbon is again released as carbon dioxide. This process is part of the global carbon cycle. Through the use of biomass for energy and materials, eg. in biomass fuelled power plants, parts of this cycle is controlled by man. Combining these biomass systems with carbon capture and storage technologies, so called bio-energy with carbon capture and storage, BECCS, is achieved. BECCS systems results in net-negative carbon dioxide emissions, ie. the removal of carbon dioxide from the atmosphere. In comparison with other geoengineering options, BECCS has been suggested as a low-risk, near-term tool to effectively remove carbon from the atmosphere.

Carbon air capture

Main article: Carbon air capture

See also: Carbon dioxide air capture and BECS

It is notable that the availability of cheap energy and appropriate sites for geological storage of carbon may make carbon dioxide air capture viable commercially. It is, however, generally expected that carbon dioxide air capture may be uneconomic when compared to carbon capture and storage from major sources - in particular, fossil fuel powered power stations, refineries, etc. In such cases, costs of energy produced will grow significantly. However, captured CO₂ can be used to force more crude oil out of oil fields, as Statoil and Shell have made plans to do. CO₂ can also be used in commercial greenhouses, giving an opportunity to kick-start the technology. Some attempts have been made to use algae to capture smokestack emissions[2], notably the GreenFuel Technologies Corporation, who have now shut down operations [3]. This technology has not reached commercial level yet.

Seeding oceans with iron

An oceanic phytoplankton bloom in the South Atlantic Ocean, off the coast of Argentina covering an area about 300 miles by 50 miles

See also: Iron fertilization

The so-called Geritol solution to global warming, first proposed by oceanographer John Martin, is a carbon sequestration strategy whimsically named for a tonic advertised to treat the effects of iron-poor blood. It is motivated by evidence that seeding the oceans with iron will increase phytoplankton populations, and thereby draw more carbon dioxide from the atmosphere. A report in Nature, 10 October 1996, by K. H. Coale et al., measured the effects of seeding equatorial Pacific waters with iron, finding that 700 grams of CO₂ were fixed by the resulting phytoplankton bloom per 1 gram of iron seeded.. Lenton and Vaughan found this technique to be potentially useful, but limited in its total capacity.

Opponents of this approach argue that fertilizing the ocean is dangerous and lacks any guarantee of efficacy. The original researchers themselves assert that, far from being a panacea for global warming, iron seeding may be entirely ineffective. Among their concerns are that nobody knows where the carbon goes after it is absorbed by phytoplankton. Instead of being drawn down to the ocean floor and acting as a carbon sink, the carbon could be reabsorbed by the water, effectively negating any initial gain. They also express concern that any attempt at geoengineering could result in massive, unpredictable changes to the environment. They point out that, considering the immense damage caused by adding nutrients to lakes and ponds, it would be a logical conclusion that adding nutrients to the ocean would also cause environmental damage. Large-scale growth in phytoplankton could reduce oxygen levels, creating dead zones where the ocean cannot support marine-life. They suggest that there is even the possibility that blooms would release more carbon dioxide equivalent greenhouse gas in the form of methane than it would sequester.

Societal controls

Another method being examined is to make carbon a new currency by introducing tradeable "Personal Carbon Credits". The idea being it will encourage and motivate individuals to reduce their 'carbon footprint' by the way they live. Each citizen will receive a free annual quota of carbon that they can use to travel, buy food, and go about their business. It has been suggested that by using this concept it could actually solve two problems; pollution and poverty, old age pensioners will actually be better off because they fly less often, so they can cash in their quota at the end of the year to pay heating bills, etc.

Governmental and intergovernmental action

Main article: Politics of global warming

Kyoto Protocol

Main article: Kyoto Protocol

The main current international agreement on combating climate change is the Kyoto Protocol, which came into force on 16 February 2005. The Kyoto Protocol is an amendment to the United Nations Framework Convention on Climate Change (UNFCCC). Countries that have ratified this protocol have committed to reduce their emissions of carbon dioxide and five other greenhouse gases, or engage in emissions trading if they maintain or increase emissions of these gases.

Copenhagen 2009

Main article: 2009 United Nations Climate Change Conference

The first phase of the Kyoto Protocol expires in 2012. The United Nations Climate Change Conference in Copenhagen in December 2009 will be the next in an annual series of UN meetings that followed the 1992 Earth Summit in Rio. In 1997 the talks led to the Kyoto Protocol, Copenhagen is the world's chance to agree a successor to Kyoto that will bring about meaningful carbon cuts.

Encouraging use changes

Carbon emissions trading

Main article: Carbon emissions trading

The European Union Emission Trading Scheme (EU ETS) is the largest multi-national, greenhouse gas emissions trading scheme in the world. It commenced operation on 1 January 2005, and all 25 member states of the European Union participate in the scheme which has created a new market in carbon dioxide allowances estimated at 35 billion Euros (US$43 billion) per year. The Chicago Climate Exchange was the first (voluntary) emissions market, and is soon to be followed by Asia's first market (Asia Carbon Exchange). A total of 107 million metric tonnes of carbon dioxide equivalent have been exchanged through projects in 2004, a 38% increase relative to 2003 (78 Mt CO₂e).

With the creation of a market for trading carbon dioxide emissions within the Kyoto Protocol, it is likely that London financial markets will be the centre for this potentially highly lucrative business; the New York and Chicago stock markets may have a lower trade volume than expected as long as the US maintains its rejection of the Kyoto).

Twenty three multinational corporations have come together in the G8 Climate Change Roundtable, a business group formed at the January 2005 World Economic Forum. The group includes Ford, Toyota, British Airways and BP. On 9 June 2005 the Group published a statement stating that there was a need to act on climate change and claiming that market-based solutions can help. It called on governments to establish "clear, transparent, and consistent price signals" through "creation of a long-term policy framework" that would include all major producers of greenhouse gases.

The Regional Greenhouse Gas Initiative is a proposed carbon trading scheme being created by nine North-eastern and Mid-Atlantic American states; Connecticut, Delaware, Maine, Massachusetts, New Hampshire, New Jersey, New York, Rhode Island and Vermont. The scheme was due to be developed by April 2005 but has not yet been completed.

Carbon tax

Main article: Carbon tax

In 1991, Sweden introduced the world's first carbon tax. The UK has had a Climate Change Levy on fossil-fuel-based electricity generation since 2001. Plans for a carbon tax in New Zealand were abandoned after the 2005 elections.

In May 2008, the Bay Area Air Quality Management District, which covers nine counties in the San Francisco Bay Area, passed a carbon tax of 4.4 cents per ton.

Non-governmental approaches

Legal action

In some countries, those affected by climate change may be able to sue major producers, in a parallel to the lawsuits against tobacco companies. Although proving that particular weather events are due specifically to global warming may never be possible, methodologies have been developed to show the increased risk of such events caused by global warming.

For a legal action for negligence (or similar) to succeed, "Plaintiffs … must show that, more probably than not, their individual injuries were caused by the risk factor in question, as opposed to any other cause. This has sometimes been translated to a requirement of a relative risk of at least two." Another route (though with little legal bite) is the World Heritage Convention, if it can be shown that climate change is affecting World Heritage Sites like Mount Everest.

Legal action has also been taken to try to force the U.S. Environmental Protection Agency to regulate greenhouse gas emissions under the Clean Air Act, and against the Export-Import Bank and OPIC for failing to assess environmental impacts (including global warming impacts) under NEPA.

According to a 2004 study commissioned by Friends of the Earth, ExxonMobil and its predecessors caused 4.7 to 5.3 percent of the world's man-made carbon dioxide emissions between 1882 and 2002. The group suggested that such studies could form the basis for eventual legal action.

Personal choices

While many of the proposed methods of mitigating global warming require governmental funding, legislation and regulatory action, individuals and businesses can also play a part in the mitigation effort. Environmental groups encourage individual action against global warming, often aimed at the consumer. Common recommendations include lowering home heating and cooling usage, burning less gasoline, supporting renewable energy sources, buying local products to reduce transportation, turning off unused devices, and various others. A geophysicist at Utrecht University has urged similar institutions to hold the vanguard in voluntary mitigation, suggesting the use of communications technologies such as videoconferencing to reduce their dependence on long-haul flights.

Business opportunities and risks

In addition to government action and the personal choices individuals can make, the threat posed by global warming provides business opportunities to be exploited and risks to be mitigated.

There has also been business action on climate change.

On 9 May 2005 Jeff Immelt, the chief executive of General Electric (GE), announced plans to reduce GE's global warming related emissions by one percent by 2012. "GE said that given its projected growth, those emissions would have risen by 40 percent without such action."

On 21 June 2005 a group of leading airlines, airports and aerospace manufacturers pledged to work together to reduce the negative environmental impact of the aviation industry, including limiting the impact of air travel on climate change by improving fuel efficiency and reducing carbon dioxide emissions of new aircraft by fifty percent per seat kilometre by 2020 from 2000 levels. The group aims to develop a common reporting system for carbon dioxide emissions per aircraft by the end of 2005, and pressed for the early inclusion of aviation in the European Union's carbon emission trading scheme.

Territorial policies of mitigation

See also: List of countries by carbon dioxide emissions

United States

Efforts to reduce greenhouse gas emissions by the United States include their energy policies which encourage efficiency through programs like Energy Star, Commercial Building Integration, and the Industrial Technologies Program. On 12 November 1998, Vice President Al Gore symbolically signed the Kyoto Protocol, but he indicated participation by the developing nations was necessary prior its being submitted for ratification by the United States Senate.

The US and global warming mitigation

In 2007, Transportation Secretary Mary Peters, with White House approval, urged governors and dozens of members of the House of Representatives to block California’s first-in-the-nation limits on greenhouse gases from cars and trucks, according to e-mails obtained by Congress. The U.S. Climate Change Science Program is a group of about twenty federal agencies and US Cabinet Departments, all working together to address global warming.

US attempts to suppress science of global warming

The U.S. government has pressured American scientists to suppress discussion of global warming, according to the testimony of the Union of Concerned Scientists to the Oversight and Government Reform Committee of the U.S. House of Representatives. "High-quality science" was "struggling to get out," as the Bush administration pressured scientists to tailor their writings on global warming to fit the Bush administration's skepticism, in some cases at the behest of an ex-oil industry lobbyist. "Nearly half of all respondents perceived or personally experienced pressure to eliminate the words 'climate change,' 'global warming' or other similar terms from a variety of communications." Similarly, according to the testimony of senior officers of the Government Accountability Project, the White House attempted to bury the report "National Assessment of the Potential Consequences of Climate Variability and Change," produced by U.S. scientists pursuant to U.S. law. Some U.S. scientists resigned their jobs rather than give in to White House pressure to underreport global warming.

Mitigation in developing countries

In order to reconcile economic development with mitigating carbon emissions, developing countries need particular support, both financial and technical. One of the means of achieving this is the Kyoto Protocol's Clean Development Mechanism (CDM). The World Bank's Prototype Carbon Fund is a public private partnership that operates within the CDM.

In July 2005 the U.S., China, India, Australia, as well as Japan and South Korea, agreed to the Asia-Pacific Partnership for Clean Development and Climate. The pact aims to encourage technological development that may mitigate global warming, without coordinated emissions targets. The highest goal of the pact is to find and promote new technology that aid both growth and a cleaner environment simultaneously. An example is the Methane to Markets initiative which reduces methane emissions into the atmosphere by capturing the gas and using it for growth enhancing clean energy generation. Critics have raised concerns that the pact undermines the Kyoto Protocol.

However, none of these initiatives suggest a quantitative cap on the emissions from developing countries. This is considered as a particularly difficult policy proposal as the economic growth of developing countries are proportionally reflected in the growth of greenhouse emissions. Critics of mitigation often argue that, the developing countries' drive to attain a comparable living standard to the developed countries would doom the attempt at mitigation of global warming. Critics also argue that holding down emissions would shift the human cost of global warming from a general one to one that was borne most heavily by the poorest populations on the planet.

In an attempt to provide more opportunities for developing countries to adapt clean technologies, UNEP and WTO urged the international community to reduce trade barriers and to conclude the Doha trade round "which includes opening trade in environmental goods and services".

Population Control

Population density by country

Various organizations promote population control as a means for mitigating global warming. Proposed measures include improving access to family planning and reproductive health care and information, reducing natalistic politics, public education about the consequences of continued population growth, and improving access of women to education and economic opportunities.

Population control efforts are impeded by there being somewhat of a taboo in some countries against considering any such efforts. Also, various religions discourage or prohibit some or all forms of birth control.

Population size has a different per capita effect on global warming in different countries, since the per capita production of anthropogenic greenhouse gases varies greatly by country.

Costs of mitigation

The Stern Review proposes stabilising the concentration of greenhouse-gas emissions in the atmosphere at a maximum of 550ppm CO₂e by 2050. The Review estimates that this would mean cutting total greenhouse-gas emissions to three quarters of 2007 levels. The Review further estimates that the cost of these cuts would be in the range -1.0 to +3.5% of GDP, with an average estimate of approximately 1%. Stern has since revised his estimate to 2% of GDP. The Review emphasises that these costs are contingent on steady reductions in the cost of low-carbon technologies. Mitigation costs will also vary according to how and when emissions are cut: early, well-planned action will minimise the costs.

One way of estimating the cost of reducing emissions is by considering the likely costs of potential technological and output changes. Policy makers can compare the marginal abatement costs of different methods to assess the cost and amount of possible abatement over time. The marginal abatement costs of the various measures will differ by country, by sector, and over time.

Limitations of mitigation

Mitigation technologies aimed at reducing emissions, as opposed to enhancing sinks, do not seek to remove greenhouse gases from the atmosphere. As such, their efficacy at reversing global warming is limited.

See also

• Adaptation to global warming
• Alternative propulsion
• Avoiding Dangerous Climate Change
• Carbon diet
• Climate change response
• Coalization
• Contraction and Convergence
• Copenhagen Accord
• Forestalment
• Hell and High Water: Global Warming
• Low carbon diet
• Mitigation of peak oil
• Oil phase-out
• Overpopulation
• QELRO
• Smart growth
• Sustainable transport
• Zero-carbon economy

By country

• Debate over China's economic responsibilities for climate change mitigation
• Mitigation of global warming in Australia
• European Climate Change Programme

References

• IPCC/TEAP (2005), "Special Report: Safeguarding the Ozone Layer and the Global Climate System: Issues related to Hydrofluorocarbons and Perfluorocarbons - Summary for Policymakers"
• Climate Change:Facts and Impacts An introduction to the issue of climate change along with current and future impacts

External links

Official

Worldwide

• Intergovernmental Panel on Climate Change - Includes the Working Group III Report "Mitigation of Climate Change" as part of the Fourth Assessment Report

European Union

• European Union's European Climate Change Programme
• EU New Energy Policy
• European Union Greenhouse Gas Emission Trading Scheme (EU ETS)
• Transport:
  • Community strategy to reduce CO2 from light vehicles.
  • EU Transport and Environment.
• United Kingdom's Climate Change Programme
• The Stern Review on the economics of climate change - Parts III and IV of the Stern Review are on climate change mitigation

USA

• EPA: What You Can Do.
• U.S. Mayors Climate Protection Agreement signed by 178 mayors representing nearly 40 million Americans
• California Climate Change Portal.

NGO/academic

• Climate Change Action Website
• List of ways for taking personal action on the Mitigation of Global Warming.
• Red Cross / Red Crescent Centre on Climate Change and Disaster Preparedness
• How to be more energy efficient in the home
• Working Group on Climate Change and Development (2004), "Up in Smoke? Threats from, and responses to, the impact of global warming on human development"
• Carbon Mitigation Initiative of Princeton University, BP, and Ford
• Cambridge Centre for Climate Change Mitigation Research
• Climate Alliance of 1000 European cities
• Friends of the Earth Putting costs into perspective - economic benefits from fighting climate change
• "Meeting the climate challenge: Recommendations of the International Climate Change Taskforce", January 2005
• The buildings and factories that are the greatest contributors of Global Warming in the USA are Mapped on the Green Building public build Google Map.
• New Scientific American article, September 2006
• Global Warming Newswire - published scientific studies on global warming
• A Clean Energy Future for Australia - a study on how Australia can halve it's energy related greenhouse gas emissions by 2040
• LEAP - a popular software tool for climate change mitigation assessment.

Academic

• Christian Azar and Stephen H. Schneider (2002) "Are the economic costs of stabilising the atmosphere prohibitive?", Ecological Economics 42 (1-2)
• Rivington M, Matthews KB, Buchan K and Miller D (2005) "An integrated assessment approach to investigate options for mitigation and adaptation to climate change at the farm-scale", NJF Seminar 380, Odense, Denmark, 7–8 November 2005.

Commentary

• Oliver James, The Guardian, June 30, 2005, Face the facts: For many people climate change is too depressing to think about, and some prefer to simply pretend it doesn't exist
• Chris Mooney, June 7, 2005, "Global warming and the categorical imperative"
• John Sterman & Linda Booth Sweeney, April 26, 2005, "Why “wait-and-see” won’t do"
• Calvin Jones, Action on climate change, Political and Practical
• Climate blog of the Center for American Progress Action Fund edited by Joseph J. Romm
• Climate Change Visual Debate, English version of WAVE project with support from the European Commission