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Mitigation of global warming

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Mitigation of global warming involves taking actions aimed at reducing the extent or likelihood of global warming. This is in contrast to Adaptation to global warming which involves taking action to take advantage of the positive effects of global warming while preventing or minimizing the negative effects of global warming.

Contents

Overview

The increasing scientific consensus on global warming, together with the precautionary principle and the fear of non-linear climate transitions [link] is leading to increasing action to mitigate global warming.

The European Union has set a target of limiting the global temperature rise to 2 °C 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 is 379 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. [link].

There are four categories of actions that can be taken to mitigate global warming:

  1. Reduction of energy use (conservation)
  2. Shifting from carbon-based fossil fuels to alternative energy sources
  3. Carbon capture and storage
  4. Geoengineering including carbon sequestration
Strategies for mitigation of global warming include development of new technologies, wind power, nuclear power, renewable energy, biodiesel, electric or hybrid automobiles, fuel cells, and energy conservation, carbon taxes and carbon sequestration schemes. Some environmentalist groups encourage individual action against global warming, often aimed at the consumer, and there has been business action on climate change.

Energy efficiency and conservation

Developing countries use their energy less efficiently than developed countries, getting less GDP for the same amount of energy. One important cause is old technology. Notable is the very low energy efficiency in the former communist states. Source: EIA.
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Developing countries use their energy less efficiently than developed countries, getting less GDP for the same amount of energy. One important cause is old technology. Notable is the very low energy efficiency in the former communist states. Source: EIA.

In the words of Benjamin Franklin: a penny saved is a penny earned. Energy which is saved by improvements in efficiency has, in practice, often provided good environmental benefit and provided a net cost saving 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.

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.

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

Transport

The development of new technologies, such as electric cars (and hybrids), and hydrogen cars, may reduce the consumption of oil and emissions of carbon dioxide. However, this does depend on the way the required electricity is generated, so these technologies need to be complemented by low-carbon-dioxide sources of electricity.

More mundanely, CO2 emissions standards may be applied to conventional vehicles, and effective urban planning and public transport can also reduce greenhouse gas emissions per passenger kilometer. Biofuels such as biodiesel are also a possibility.

Housing and urban planning

As well as designing buildings which are more energy efficient also suggested for hotter climates is the possibility of using lighter-coloured, more reflective materials in the development of urban areas (e.g. by painting roofs white) and planting trees [link], [link]. This saves energy because it cools buildings and reduces the urban heat island effect thus reducing the use of air conditioning. In cold climates where air conditioning accounts for only a small proportion of energy consumption, the opposite of this approach may be preferable: An increase in average city temperatures by painting roofs black decreases demand for heating fuel.[[Citing sources citation needed]]

Urban planning also has an effect on energy use. 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.

Alternative energy sources

Renewable energy

Main articles: Renewable energy and Renewable energy development

One means of reducing carbon emissions is the development of new technologies such as renewable energy. Most forms of renewable energy generate no appreciable amounts of greenhouse gases except for biofuels derived from biomass.

Generally, emissions are a fraction of fossil-fuel-based electricity generation. In some cases, notably with hydro power - once thought to be one of the cleanest forms of energy - there are unexpected results. One study shows that a hydropower plant 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.[link] This effect applies in particular to dams created by simply flooding a large area, without first clearing it of vegetation.

Thus, converting our energy sources from fossil fuel to renewable energy e.g. solar energy is an important mitigation measure, reducing the increase in radiative forcing due to increasing atmospheric concentrations of greenhouse gases.

Currently governments subsidise fossil fuels by an estimated $235 billion a year.[link] However, in some countries, government action has boosted the development of renewable energy technologies—for example, a programme 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.

In June 2005, the chief executive of BT became the first head of a British company to admit that climate change was already taking place, 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"[link].

Solar Power

Advantages
Disadvantages
Solar power at the Earth's surface, has a number of disadvantages which must be addressed as engineering problems to make it an effective source of energy supply:

Wind power

Wind often flows briskly and smoothly over water since there are no obstructions. The large and slow turning turbines of this offshore wind farm near Copenhagen take advantage of the moderate yet constant breezes at this location. Wind power is the only direct form of greenhouse effect mitigation, because it removes energy from the atmosphere.
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Wind often flows briskly and smoothly over water since there are no obstructions. The large and slow turning turbines of this offshore wind farm near Copenhagen take advantage of the moderate yet constant breezes at this location. Wind power is the only direct form of greenhouse effect mitigation, because it removes energy from the atmosphere.

Wind power is the only renewable form of energy which is a direct mitigation, drawing energy directly from the atmosphere. A wind turbine produces more than fifty times as much energy over its lifetime as is consumed by its construction and installation.[link]

Although commercial wind power was born in California in the 1980s, in 2004 nine of the ten leading wind turbine manufacturers were based in Denmark, Germany and Spain.

Biofuels

Renewable Energy in the European Union

The countries of the European Union, taken together, constitute the leading world power in the development and application of renewable energies. Promotion of renewable energies plays an important role both in the reduction of the EU dependence on foreign energy imports and in the measures which it must take to combat climate change. However, Germany is the only member of the EU that is on track to achieve the objectives set by the Kyoto protocol on climate change.

The Maastricht Treaty set an objective of promoting stable growth that is also protective of the environment. The Amsterdam Treaty added the principle of sustainable development to the objectives of the EU. Since 1997, the EU has been working towards a having renewable energies supply 12% of total EU energy consumption in 2010.

The EU and other nations have formed the group of "pioneer countries", and it promised to establish ambitious national or even regional goals to achieve global targets. The Johannesburg Renewable Energy Coalition (JREC) has a total of more than 80 member countries, the EU, Brazil, South Africa and New Zealand among others.

In the European Conference for Renewable Energy of Berlin 2004, the EU defined ambitious goals of its own. The recommendation is to meet a 20% of total energy consumption requirements with renewable energy sources by 2020. Up until that point, the EU had only hoped to duplicate this percentage of 12.5% by 2010. No goal had been set for 2020.

Nuclear energy

In some countries (such as the UK and Australia, the latter of which has no commercial nuclear energy) there are also discussions about the future role of nuclear power as a possible alternative to fossil fuels with low carbon emissions. Different life cycle studies of nuclear power have come to wildly different conclusions about their emissions. According to one study (van Leeuwen and Smith 2001-2005)[link], carbon dioxide emissions from nuclear power per kilowatt hour are around 20-40% of those for natural gas-fired power stations and about 4 or 5 times greater than that produced by some renewables. But several others show similar emissions from nuclear power and renewables [link].

On study argues that certain gas cogeneration plants are 3-4 times more cost effective than nuclear power for abating CO2 emissions, if all the heat produced can be used onsite or in a local heating sysem. However, nuclear power also produces heat which could be used in similar ways. The study found similar costs for windpower and nuclear power if not including external costs (such as back-up power).[link]

An important fact to keep in mind is that the bulk of this CO2 is in fact generated by burning coal to generate electricity for the uranium enrichment process. Coal generation is by far the most polluting form of electricity generation from the global warming point of view.[link] If instead nuclear power plants generated this electricity, then this pollution would be eliminated. This sort of pollution also applies to renewables since the construction of the power plants require the mining and refinement of raw materials.

It is sometimes said that, using current nuclear technologies, if all fossil-fuel power stations were replaced by nuclear ones, there would only be enough uranium to supply them for a few years. It is true that all known orebodies would run out very quickly. But the definition of an orebody is "an occurrence of mineralization from which the metal is economically recoverable". If the cost of uranium were to double, the amount of available uranium would increase many times.[link] Such a cost increase would have only a small effect on the consumer, as the cost of fuel is a fraction of the other operating costs, but the lower-quality ores involved would contribute to higher CO2 emissions.[link] There are a number of alternative nuclear fission technologies, such as already existing breeder reactors, which could vastly extend fuel supplies if required, but they are not without their own issues.

The use of nuclear energy to combat global warming conflicts with some countries' decisions to phase out nuclear power for environmental, social and political reasons.

In the past, nuclear energy was a source of other potent greenhouse gases such as chloro- and fluorohydrocarbons, whose precise influence from nuclear generation has been difficult to quantify[link]. Most of these emissions were traditionally produced because of leaks in freon cooling systems. Those systems have since switched over to more environmentally friendly cooling gases. [link]

Decentralised generation

A variety of technologies permitting decentralised electricity generation may permit the reduction of electricity transmission losses and in some cases higher efficiency. These include small-scale solar and wind generation, and small-scale combined heat and power plants. UK power company Powergen markets a microCHP plant which it says allows a household to save 20% of its CO2 emissions per year (1.5 tons).[link]

Carbon capture and storage

''Main article: Carbon Capture and Storage

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 (2006) no powerplant operates with a full carbon capture and storage system.

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. Capturing and compressing CO2 requires much energy and would increase the energy needs of a plant with CCS by about 10-40%. This and other system costs is estimated to increase the costs of energy from a power plant with CCS by 30-60% depending on the specific circumstances.

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.

Geoengineering

Main article: Planetary engineering

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 and give preliminary answers to two questions: can these options work and could they be carried out a reasonable cost. They also sought to encourage dicussion 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.".

Some conspiracy theorists use this report as an argument when discussing so-called chemical contrails, or chemtrails, as the chapter on mitigation specifically regards large scale spraying of the skies as a possible solution to solving global warming, among others.

Carbon sequestration

Main article: Carbon sequestration

Carbon sequestration has been proposed as a method of reducing the amount of radiative forcing, though concerns have been expressed about its long-term effects.

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.

Carbon can be removed from the atmosphere, either by enhancing natural sinks or capturing carbon dioxide directly from emission sources and subsequently storing it away (or even removing CO2 directly from air).

In practice, capture is likely to be uneconomic unless applied to major sources - in particular, fossil fuel powered power stations. In such cases, costs of energy could well grow by 50%. However, captured CO2 can be used to force more crude oil out of oil fields, as Statoil and Shell have made plans to do.[link]

Seeding oceans with chalk

For example, there is the possibility of countering acidification of the oceans by dumping (alkaline) chalk in the oceans. This solution engenders its own problems, however - notably the energy needed for the largescale mining and processing required.[link]

Seeding oceans with iron

The so-called Geritol solution to global warming 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[link]. Given the US EPA's current estimate of 1.2×1013 kg of annual atmospheric CO2 surplus, and the current 2006 market asking price of US$ 35/tonne for 65% iron ore fines, less than US$ 800 million worth of iron ore distributed in the equatorial Pacific annually would suffice to entirely offset surplus carbon emissions.

Opponents of this approach argue that fertilizing the ocean is a dangerous proposition. They argue that it would not be possible to control the areas that are fertilized because the ocean is turbulent. They express concern that this approach would upset the current balance of the entire oceanic food chain. 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. They suggest that there is even the possibility that blooms would release more greenhouse gas in the form of methane than it would sequester.[#endnote_]

Screening out sunlight

Another class of geoengineering approaches to attempt mitigation involves changing the Earth's albedo (reflectivity), to reflect more heat back out into space: a 0.5% albedo increase would roughly halve the effect of CO2 doubling [link]. Methods which have been proposed could include: releasing dust, sulfuric acid or reflecting micro-balloons into the stratosphere; enhancing low-level clouds [link]; creating a Saturn-like ring of small particles [link], or putting a very large mirror or wire mesh in space (perhaps at the L1 point between the Earth and the Sun)[link]. The cooling effect that volcanic eruptions often have on the climate due to ash particles in the upper atmosphere can be seen as an analogy of how these methods might work.

Governmental and Intergovernmental Action

Kyoto Protocol

Main article: Kyoto Protocol

The primary 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.

Encouraging use changes

Carbon emissions trading

Main article: Carbon emissions trading

The European Union Emission Trading Scheme (EU ETS) [link] 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. The scheme has created a new market in carbon dioxide allowances estimated at some Euro 35 billion (US$43 billion) per year.[link] 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 (tCO2e) have been exchanged through projects in 2004, a 38% increase relative to 2003 (78 Mt CO2e).[link]

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 would like a share (which is unlikely as long as the US rejects Kyoto).[link]

23 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 by 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

See also: 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.

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.[link] Although proving that particular weather events are due specifically to global warming may never be possible (Edward Lorenz (1982): "Climate is what you expect, weather is what you get"), methodologies have been developed to show the increased risk of such events caused by global warming (Stott et al. 2004).

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." (Grossman, Columbia J. of Env. Law, 2003) 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.[link]

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,[link] and against the Export-Import Bank and OPIC for failing to assess environmental impacts (including global warming impacts) under NEPA.[link]

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.[link]

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. Some environmentalist groups encourage individual action against global warming, often aimed at the consumer.

Individual actions can include:

See also [The DIY Guide to Combating Global Warming].

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 own emissions tied to global warming by one percent by 2012. GE said that given its projected growth, those emissions would have risen by 40 percent without such action.[link]

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.[link]

Mitigation in developing countries

Traditionally, economic growth tends to increase pollution as well as greenhouse gas emissions. 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 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.[link] Critics have raised concerns that the pact undermines the Kyoto Protocol. [link]

However, none of these initiative suggest quantitative cap on the emission from developing countries. This is considered as particularly difficult policy proposal as the economic growth of developing countries are proportionally reflected in the growth of greenhouse emission. Critics of mitigation often argue that, the developing coutries' drive to attain 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.

References

See also

Global Warming
Subtopics
Scientific opinion | Attribution of causes | Effects | Mitigation | Adaptation | Controversy | Politics | Economics
Related Topics
Greenhouse effect | Greenhouse gases | Temperature data | Kyoto Protocol | Long-term climate change
Intergovernmental Panel on Climate Change

External links

Official

NGO/academic

Academic

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Commentary

 

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