Geoengineering

The modern concept of geoengineering is usually taken to mean proposals to deliberately manipulate the Earth's climate to counteract the effects of global warming from greenhouse gas emissions. The National Academy of Sciences 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."

Some geoengineering techniques are based on carbon sequestration. These seek to reduce greenhouse gases in the atmosphere directly. These include direct methods (e.g. carbon dioxide air capture) and indirect methods (e.g. ocean iron fertilization). These techniques can be regarded as mitigation of global warming. Alternatively, solar radiation management techniques (e.g. stratospheric sulfur aerosols) do not reduce greenhouse gas concentrations, and can only address the warming effects of carbon dioxide and other gases; they cannot address problems such as ocean acidification, which are expected as a result for rising carbon dioxide levels. Examples of proposed geoengineering techniques include the production of stratospheric sulfur aerosols, which was suggested by Paul Crutzen, and cloud reflectivity enhancement. Most techniques have at least some side effects.

To date, no large-scale geoengineering projects have been undertaken, nor has a consensus been reached that geoengineering is desirable. Some commentators additionally suggest that consideration of geoengineering is unhelpful because it threatens to reduce the political and popular pressure for emissions reduction. Typically, the scientists and engineers proposing geoengineering strategies do not suggest that they are an alternative to emissions control, but rather an accompanying strategy. Some limited tree planting and cool roof projects are already underway, and ocean iron fertilization is at an advanced stage of research, with small scale research trials having been completed.

Definition

Geoengineering is the idea of applying planetary engineering to Earth. Geoengineering would involve the deliberate modification of Earth's environment on a large scale "to suit human needs and promote habitability". Typically, the term is used to describe proposals to counter the effects of human-induced climate change. However, others define it more narrowly as nature-integrated engineering projects. The term geoengineering is distinct from environmental damage and accidental anthropogenic climate change, which are side-effects of human activity, rather than an intended consequence. The global recovery of hydrocarbons from the subsurface using integrated geoscience and engineering technology has been termed 'petroleum geoengineering' as an activity with global impact. . Definitions of the term are not universally accepted.

Background

The field is currently experiencing a surge of interest as it has now become a broadly accepted fact that global warming is both real and dangerous. A degree of urgency in efforts to research and implement potential solutions is based on the historic failure to control emissions, and the possibility that tipping points in the Earth's climate system are close at hand. In particular the Arctic shrinkage is causing accelerated regional warming. Rapid action with geoengineering may be necessary. Other tipping points might be avoided by reducing the impact of global warming in order to stifle positive feedback and prevent the resulting accelerated climate change.

The study of geoengineering is a notably complex discipline, as it requires the collation of knowledge in:

* scientific disciplines including atmospheric chemistry, ecology, meteorology, plant biology
* engineering disciplines including aeronautical engineering, naval architecture, ballistics
* management and control disciplines such as risk management, operational research

Several notable organisations have recently, or are soon to, investigate geoengineering with a view to evaluating its potential. Notably, NASA, the Royal Society, the Institute of Mechanical Engineers, and the UK Parliament, have all held inquiries or contests aimed at discovering and evaluating current knowledge of the subject.

The major environmental organisations such as Friends of the Earth and Greenpeace have typically been reluctant to endorse geoengineering. Some have argued that any public support for geoengineering may weaken the fragile political consensus to reduce greenhouse gas emissions.

Proposed projects

Several geo-engineering projects have been proposed. The documentaries Five ways to save the world and La temperature grimpe describe many of the most notable projects. IPCC documents also detail several proposed projects.

Solar radiation management



Solar radiation management (SRM) projects seek to reduce the amount of sunlight hitting the Earth and thus counteract global warming. They do not reduce greenhouse gas concentrations in the atmosphere, and thus do not address problems such as ocean acidification caused by these gases. The phenomenon of global dimming is widely-known, and is not necessarily a geoengineering technique, occurring naturally as a result of volcanoes and major forest fires. However, its deliberate manipulation is a tool of the geoengineer.

Solar radiation management projects often have the advantage of speed. Whilst Greenhouse gas remediation offers a comprehensive possible solution to climate change, it does not give instant results; for that, solar radiation management is required.

Techniques that fall into this category include:

* Creating stratospheric sulfur aerosols
* Cool roof – using pale-coloured roofing and paving materials
* Cloud reflectivity enhancement – using fine sea water spray to whiten clouds and increase cloud reflectivity.
* Space sunshade - obstructing solar radiation with space-based mirrors or other structures

Greenhouse gas remediation



Greenhouse gas remediation projects seek to remove greenhouse gases from the atmosphere, and thus tackle the root cause of global warming. They either directly remove greenhouse gases, or alternatively seek to influence natural processes to remove greenhouse gases indirectly. These projects offer a comprehensive solution to the problem of excess greenhouse gases in the atmosphere, but they will take many years to work fully. Many projects overlap with carbon capture and storage and carbon sequestration projects, and may not be considered to be geoengineering by all commentators. Techniques in this category include:

* Iron fertilisation of the oceans
* Creating biochar (anaerobic charcoal) and burying it to create terra preta
* Biomass energy with carbon capture and storage
* Carbon air capture to remove carbon dioxide from ambient air

Arctic geoengineering

Various hydrological geoengineering projects aim to change the climate without directly or indirectly removing greenhouse gases, or directly influencing solar radiation. These principally act by limiting Arctic sea ice loss. Keeping the Arctic ice is seen by many commentators as vital, due to its role in the planet's albedo and in keeping methane, which is an important greenhouse gas, locked up in permafrost.

Heat transport

The use of vertical ocean pipes to mix cooler deep water and warmer surface water, has been proposed by James Lovelock.

Justification

The use of geoengineering to tackle climate change is advocated for several specific reasons:

Tipping points and positive feedback



It is argued that climate change has already, or is soon to, pass one or more tipping pointswhere aspects of the climate system may 'tip' from one stable state to another stable state, much like a glass tipping over. When the new stable state is reached, it may trigger or accelerate warming positive feedback effects, such as the collapse of Arctic sea ice triggering the release of methane from permafrost in Siberia. The "nightmare scenario" is that a domino effect will occur, with successive parts of the climate system tipping one after the other, with each change being caused by the previous one and causing the next one. Such a situation will lead to spiralling and potentially sudden climate change.

The precise identity of such "tipping points" is not clear, with scientists taking differing views on whether specific systems are capable of "tipping" and the point at which this "tipping" will occur. An example of a previous tipping point is that which preceded the rapid warming leading up to the Paleocene–Eocene Thermal Maximum. Once the tipping point is reached, cuts in greenhouse gas emissions will not be able to reverse the change. Depending on the precise nature of the individual system that "tips", positive feedbacks may occur, with warming causing more warming, which causes yet more warming—a runaway global warming event.Therefore, some commentators suggest that more conservative use of resources is not enough to mitigate global warming. Even if all greenhouse emissions suddenly came to a complete halt, the world would continue to be affected for centuries, and further warming may occur due to positive feedback. Conservation of resources and reduction of greenhouse emissions, used in conjunction with geoengineering, are therefore considered a viable option. Geoengineering offers the hope of temporarily reversing some aspects of climate change and allowing the natural climate to be substantially preserved whilst greenhouse gas emissions are brought under control and removed from the atmosphere by natural or artificial processes.

Precautionary principle

Bearing in mind the threats from climate change, it can be argued that attempting geoengineering represents a lesser risk than not pursuing such strategies. While the understanding of geoengineering techniques is limited, the risks of global warming are at least partially understood, and are severe.

Costs

Some geoengineering techniques, such as the use of pale-coloured materials for roofing and paving, can be achieved at little or no cost, and may even offer a financial payback. It is therefore possible to argue that certain implementations of such techniques are preferable to cutting carbon emissions on cost grounds alone.

Political viability

It has been argued that regardless of the economic, scientific and technical aspects, the difficulty of achieving concerted political action on climate change requires other approaches. Those arguing political expediency say the difficulty of achieving meaningful emissions cuts and the effective failure of the Kyoto Protocol demonstrate the practical difficulties of achieving carbon dioxide emissions reduction by the agreement of the international community. However, others point to support for geoengineering proposals among think tanks with a history climate change skepticism and opposition to emissions reductions as evidence that the prospect of geoengineering is itself already politicized and being promoted as part of an argument against the need for (and viability of) emissions reductions; that, rather than geoengineering being a solution to the difficulties of emissions reductions, the prospect of geoengineering is being used as part of an argument to stall emissions reductions in the first place.

Risks and criticisms

Various criticisms have been made of geoengineering. However, the existence of criticism should not be taken to mean that those raising it are opposed to a particular technique, but rather that they are pointing out a potential disadvantage or downside which may need to be monitored or controlled, or may alternatively weigh against a particular technique. Some commentators appear fundamentally opposed, however. Individuals such as Raymond Pierrehumbert have called for a moratorium on geoengineering techniques.

Ineffectiveness

The effectiveness of the schemes proposed may fall short of predictions. In the example of ocean iron fertilization, for example, the amount of carbon dioxide removed from the atmosphere may be much lower than predicted, as carbon taken up by plankton may be released back into the atmosphere from dead plankton, rather than being carried to the bottom of the sea and sequestered.



Incomplete solution to CO2 emissions

Techniques that do not remove greenhouse gases from the atmosphere may control global warming, but do not reduce other effects from these gases, such as ocean acidification. Whilst not an argument against geoengineering per se, this is an argument against reliance on geoengineering to the exclusion of greenhouse gas reduction.

Control and predictability problems

Many members of the scientific and technical communities fear that the full effects of various geoengineering schemes are not well understood. The failure of the ambitious Biosphere 2 facility is one example of a complex project that was unsuccessful because scientists still have a limited understanding of how earth systems work together.

Performance of the systems may become ineffective, unpredictable or unstable as a result of external events, such as volcanic eruptions, phytoplankton blooms, El Niño, solar flares, etc., potentially leading to profound and unpredictable disruption to the climate system.

It may be difficult to predict the effectiveness of projects, with models of techniques giving widely varying results. In the instances of systems which involve tipping points, this may result in irreversible effects. Climate modelling is far from an exact science even when applied to comparatively well-understood natural climate systems, and it is made more complex by the need to understand novel and unnatural processes which by definition lack relevant observation data.

Side effects

The techniques themselves may cause significant foreseen or unforeseen harm. For example, the use of reflective balloons may result in significant litter, which may be harmful to wildlife.

Ozone depletion is a risk of some geoengineering techniques, notably those involving sulfur delivery into the stratosphere.

The active nature of geoengineering may in some cases create a clear division between winners and losers. Most of the proposed interventions are regional, such as albedo modification in the Arctic. Necessarily, such interventions compel those in the affected regions to tolerate the effects of geoengineering for the supposed benefit of the global climate.

There may be unintended climatic consequences, such as changes to the hydrological cycle including droughts or floods, caused by the geoengineering techniques, but possibly not predicted by the models used to plan them. Such effects may be cumulative or chaotic in nature, making prediction and control very difficult.

Unreliable systems

The performance of the interventions may be inconsistent due to mechanical failure, non-availability of consumables or funding problems.

The geoengineering techniques would, in many instances, be vulnerable to being switched off or deliberately destroyed. As examples, cloud making ships could be switched off or sunk and space mirrors could be tilted to make them useless. Anyone capable of exerting such power may seek to abuse it for commercial gain, military advantage or simple terrorism.

Weaponisation

Weaponisation of geoengineering techniques is generally prohibited by the Environmental Modification Convention. However, this does not eliminate the risk. Geoengineering techniques may be used as a weapon of mass destruction, creating droughts or famines designed to destroy or disable an enemy. They could also be used simply to make battlefield conditions more favourable to one side or the other in a war (such as in Operation Popeye). For example, laser-guided weapons are confounded by clouds, and thus switching off cloud machines would favour forces using such weapons, and switching them on would favour ground forces defending against them.

Whilst laws or treaties may prevent the manipulation of the climate as a weapon of war, it could be argued that geoengineering is itself a manipulation, and thus destroying or disabling the geoengineering structures is not prohibited. A new legal framework may be necessary in the event that large-scale geoengineering becomes established.

Despite the capacity of the military-industrial complex to investigate and deploy geoengineering, their involvement has proved controversial. Carnegie’s Ken Caldeira said, "It will make it harder to achieve broad consensus on developing and governing these technologies if there is suspicion that gaining military advantage is an underlying motivation for its development.."

Effect on sunlight, sky and clouds

Managing solar radiation using aerosols or cloud cover will change the ratio between direct and indirect solar radiation. This may affect plant life and solar energy. There will be a significant effect on the appearance of the sky from aerosol projects, notably a hazing of blue skies and a change in the appearance of sunsets. Aerosols may affect the formation of clouds, especially cirrus clouds.

Moral hazard

The existence of such techniques may reduce the political and social impetus to reduce carbon emissions.

Other criticism comes from those who see geoengineering projects as reacting to the symptoms of global warming rather than addressing the real causes of climate change. Because geoengineering is a form of controlling the risks associated with global warming, it leads to a moral hazard problem. The problem is that knowledge that geoengineering is possible could lead to climate impacts seeming less fearsome, which could in turn lead to a weaker commitment to reducing greenhouse gas emissions.

Lack of global control

Geoengineering opens up various political and economic issues. David Keith argues that the cost of geoengineering the Earth is within the realm of small countries, large corporations, or even very wealthy individuals. Steve Rayner agrees that not all geoengineering possibilities are expensive, and that some, such as ocean iron fertilisation, are within the reach of very wealthy individuals, calling them a "Greenfinger" (after the fictional Goldfinger) David Victor suggests that geoengineering is within the reach of any individual who has a small fraction of the bank account of Bill Gates, who takes it upon him or her self to be the "self-appointed protector of the planet".

This effectively eliminates any control over who gets to decide when to cool the Earth and how often this should be done. The resulting power would be enormous, and could not necessarily be readily controlled by legal, political or regulatory systems. These legal and regulatory systems may themselves be far less powerful than the geoengineers controlling the climate become.

It is quite feasible for carbon offsetting firms to set up unregulated, unsupervised and dangerous geoengineering projects. This may be done in order to sell carbon credits to individuals and firms.

Geoengineering schemes have the potential to cause significant environmental damage, and may even end up releasing further greenhouse gases into the atmosphere. Opposition to some early schemes has been intense, with respected environmental groups campaigning against them.

Implementation issues

There is no general consensus that geoengineering is safe, appropriate or effective, for the reasons listed above. The issue of moral hazard means that many environmental groups and campaigners are reluctant to advocate geoengineering for fear of reducing the imperative to cut greenhouse gas emissions. Other environmentalists see calls for geoengineering as part of an explicit strategy to delay emissions reductions on the part of those with connections to coal and oil industries.

All proposed geoengineering techniques require implementation on a relatively large scale, in order to make a significant difference to the Earth's climate. The least costly schemes are budgeted at a cost of millions, with many more complex schemes such as space sunshade costing far more.

Many techniques, again such as space sunshade, require a complex technical development process before they are ready to be implemented. There is no clear institutional mechanism for handling this research and development process. As a result, many promising techniques do not have the engineering development or experimental evidence to determine their feasibility or efficacy at present.

Once a technique has been developed and tested, its implementation is still likely to be difficult. Climate change is by nature a global problem, and therefore no one institution, company or government is responsible for it. The substantial costs of most geoengineering techniques therefore cannot currently be apportioned. Roll-out of such technologies is therefore likely to be delayed until these issues can be resolved. A notable exception is the use of small albedo manipulation projects, known as cool roof, in which the colour of roofing or paving surfaces can be manipulated to reflect solar radiation back into space. These can be, and are, implemented by individuals, companies and governments without controversy.

Due to the radical changes caused by geoengineering interventions, legal issues are also an impediment to implementation. The changes resulting from geoengineering necessarily benefit some people and disadvantage others. There may therefore be legal challenges to the implementation of geoengineering techniques by those adversely affected by them.

Evaluation of geoengineering

Few field experiments in geoengineering have been carried out. Most of what is known about the suggested techniques is based on simulations from global climate models and other computer modelling techniques. Some techniques are based on natural phenomena such as stratospheric sulfur aerosols and cloud condensation nuclei, the properties of which are already understood from other research, such as that following the 1991 eruption of Mount Pinatubo.

Evaluation of the relative merits of each technology is difficult, especially bearing in mind the difficulties of modelling and the lack of engineering development of many ideas.

A study by Lenton and Vaughan evaluated various techniques and determined that some were capable of reversing the warming effect of a doubling of the level of carbon dioxide in the atmosphere when compared to pre-industrial levels.

From http://en.wikipedia.org/

Environment of China

This article documents the environment of mainland People's Republic of China. One of the serious negative consequences of the People's Republic of China's rapid industrial development has been increased pollution, smog, and degradation of natural resources. Much solid waste is not properly disposed of. Water pollution is a source of health problems across the country, and air pollution causes up to 1,750,000 premature deaths each year. China's polluted environment is largely a result of the country's rapid development and consequently a large increase in primary energy consumption, which is primarily provided by coal power plants. China has pursued a development model which prioritizes exports-led growth (similar to many other East Asian countries). Forbes Magazine reports that all 10 of the 10 most polluted cities in the world are in China.

Nevertheless, China has achieved some significant improvements to its environment during the recent years. According to the World Bank, 'China is one of a few countries in the world that have been rapidly increasing their forest cover. It is managing to reduce air and water pollution.'

As part of US$498 billion economic stimulus package of November 2008 (the largest in China's history), the government plans to enhance sewage and rubbish treatment facilities and prevent water pollution, accelerate green belt and natural forest planting programs, and increase energy conservation initiatives and pollution control projects.

Environmental issues

Efforts to control China's pollution problem have become a top priority of the Chinese leadership. In March 1998, the State Environmental Protection Administration (SEPA) was officially upgraded to a ministry-level agency, reflecting the growing importance the PRC Government places on environmental protection. Beginning in 2006, the government greatly expanded expenses into environmental protection, and a series of new laws have been passed. Enforcement of these laws is also being expanded. The PRC has strengthened its environmental legislation and made some progress in stemming environmental deterioration. During the 11th 5-Year Plan (2006-2010), the PRC plans to reduce total emissions by 10% and bring China's energy efficiency up by 20%. Beijing in particular is investing heavily in pollution control as part of its campaign to host a successful Olympiad in 2008. Some cities have seen improvement in air quality in recent years. In the first half of 2007, China's total energy consumption per unit of output improved by 2.8% and China's sulfur dioxide emissions fell by 0.6%, showing that these new measures have the potential to slow down pollution growth.

Since 2002, the number of complaints to the environmental authorities has increased by 30% every year, reaching 600,000 in 2004; while the number of mass protests caused by environmental issues has grown by 29% every year.

The Xinhua News Agency has quoted an environmental official, Wang Jinnan, as saying that more than 410,000 Chinese die as a result of pollution each year. The Financial Times said a World Bank report, entitled Cost of Pollution in China, (prepared with the cooperation of the State Environmental Protection Agency) found up to 760,000 people die prematurely each year in China because of air and water pollution. High levels of air pollution in China's cities leads to 350,000-400,000 premature deaths, it said. Another 300,000 die because of indoor air of poor quality. The newspaper article, quoting World Bank advisers and Chinese officials, also said that the report omitted research showing that there are 60,000 premature deaths each year because of water of poor quality.

The Chinese government has placed a greater concern on environmental issues since the early 21st century. In 2004, the central government instituted the Green Gross Domestic Product project, in order to determine the true gross domestic product, adjusted to compensate for negative environmental effects. The results were so much worse than projected that the program was suspended entirely in 2007. In 2005, the eleventh five-year plan contained special emphasis on the nation's environmental degradation. In his annual address in 2007, premier Wen Jiabao made 48 references to "environment," "pollution," or "environmental protection." In addition, the Chinese government attempted to hold national "No Car Days" throughout nearly 100 cities, including Beijing, in which cars would be banned on central roads. However, it was largely ignored.

From http://en.wikipedia.org/

Energy and Environment

Energy and Environment describes itself as "an interdisciplinary journal aimed at natural scientists, technologists and the international social science and policy communities covering the direct and indirect environmental impacts of energy acquisition, transport, production and use." The journal's publisher is Multi-Science and its editor since 1996 is Sonja Boehmer-Christiansen, who is a former Reader in Geography at the University of Hull in England and writer on the political and policy aspects of climate change. The journal's editorial advisory board has 20 members, including 11 professors and 5 other PhDs in 2008.

Energy and Environment ("E&E") has been published since 1989. People who have published in this journal include Richard Tol, and Gary Yohe. The journal is not listed in the ISI's Journal Citation Reports indexing service for academic journals, although it is included in Scopus, which lists it as a trade journal, with coverage from 1995. According to the WorldCat.org database, the journal can be found at 39 libraries worldwide, at universities and the library of congress.

The journal's peer-review process has at times been criticised for publishing substandard papers. Roger A. Pielke (Jr), who published a paper on hurricane mitigation in the journal, said in a post answering a question on Nature's blog in May about peer-reviewed references and why he published in E&E: "...had we known then how that outlet would evolve beyond 1999 we certainly wouldn't have published there. The journal is not carried in the ISI and thus its papers rarely cited. (Then we thought it soon would be.) We were invited to submit a piece in 1997 or 1998 and we had this in prep and sent it in."

People considered climate skeptics or contrarians, including Sallie Baliunas, Ian Castles, Bjorn Lomborg, Patrick Michaels, Ross McKitrick, Stephen McIntyre, Roger Pielke Jr. and Willie Soon, have published in the journal. Skeptics on the journal's editorial staff include Boehmer-Christiansen herself and anthropologist Benny Peiser. Some of the journal's articles opposing the scientific consensus on climate change have been quoted by policy makers known to be skeptical of the subject, such as U.S. Senator James Inhofe and U.S. Congressman Joe Barton. When asked about the publication of these papers Boehmer-Christiansen replied, "I'm following my political agenda -- a bit, anyway. But isn't that the right of the editor?"

The publication's ISSN is 0958-305X and OCLC is 21187549.

From http://en.wikipedia.org/

Economics of global warming

The economics of global warming refers to the projected size and distribution of the economic costs and benefits of global warming, and to the economic impacts of actions aimed at the mitigation of global warming. Estimates come from a variety of sources, including integrated assessment models, which seek to combine socio-economic and biophysical assessments of climate change.

At an Intergovernmental Panel on Climate Change (IPCC) conference in April 2007, delegates from 120 nations discussed the specific economic and societal costs of mitigating global warming, and eventually approved the IPCC Fourth Assessment Report.

Projections of climate change

Integrated assessment models provide different projections as to the amount of future climate change. The IPCC have produced a report (SRES) where a number of different future scenarios are described. The scenarios differ in whether the future will be:

* 'more environmental' (scenarios with the 'B' prefix) or 'market-oriented' (scenarios with the 'A' prefix)
* 'more global' (scenarios with the '1' suffix) or 'more regional' (scenarios with the '2' suffix)

Forecasts of changes in global mean temperature for these scenarios are given in the IPCC report.The 'best estimate' global mean temperature increase (2090 to 2099 relative to the period 1980-1999) for these scenarios range from 1.8 degrees Celsius for the B1 scenario, to 4.0 degrees Celsius for the A1FI scenario. The 'likely' range (greater than 66% probability) over the same period for all the SRES scenarios is a global mean temperature increase of between 1.1 to 6.4 degrees Celsius.

A 2009 study by the MIT Joint Program on the Science and Policy of Global Change looked at future predictions of climate change.According to this study, there is a 57% likelihood of exceeding a 5 degrees Celsius increase in global mean temperature by 2100 (relative to the base years of 1981 to 2000). This is the 'no policy' estimate. In the 'policy' estimate, where greenhouse gas emissions are controlled to relatively low levels, the likeliest increase in global mean temperature for the same period is between 2 and 2.5 degrees Celsius.

According to a 2008 study by the Hadley Centre, for a 'business-as-usual' increase in global greenhouse gas emissions of 132% (from 1990 emission levels) by 2050, the rise in global mean temperature will be between 5.5 and 7.1 degrees Celsius (relative to pre-industrial levels) by 2100.In this estimate, the likeliest increase in global mean temperature is 5.5 degrees Celsius (50% chance of occurring), and the the worst case increase in global mean temperature is 7.1 degrees Celsius (10% chance of occurring). The Hadley Centre study also looked at other emissions scenarios. In a scenario where there is an early and rapid decline in emissions (a 47% decrease from 1990 emission levels by 2050), global mean temperature is predicted to rise 2.1 to 2.8 degrees Celsius by 2100. For this scenario, 2.1 degrees Celsius is the likeliest increase in global mean temperature (50% chance of occurring), and 2.8 degrees Celsius the worst case increase in global mean temperature (10% chance of occurring).

Economic impacts of global warming

Aggregate impacts

The IPCC Fourth Assessment Report, published in 2007, looked at the aggregate economic impacts of climate change:

to impose net annual costs, which will increase over time as global temperatures increase. Peer-reviewed estimates of the social cost of carbon in 2005 average US$12 per tonne of CO2, but the range from 100 estimates is large (-$3 to $95/tCO2). This is due in large part to differences in assumptions regarding climate sensitivity, response lags, the treatment of risk and equity, economic and non-economic impacts, the inclusion of potentially catastrophic losses and discount rates. Aggregate estimates of costs mask significant differences in impacts across sectors, regions and populations and very likely underestimate damage costs because they cannot include many non-quantifiable impacts.

Aggregate impacts have also been quantified in other metrics: for example, climate change over the next century is likely to adversely affect hundreds of millions of people through increased coastal flooding, reductions in water supplies, increased malnutrition and increased health impacts.

According to the IPCC Report, with medium confidence (around 5/10 chance of being correct): 'aggregate market sector impacts of 2°C global mean temperature increase, above the 1990 level, will be plus or minus a few percent of global GDP, with most people in the world negatively affected. Studies of aggregate economic impacts found net damages beyond temperature increases of 2 to 3°C above 1990 levels, with increasing damages at higher magnitudes of climate change.' The Report adds that: 'On balance, the current generation of aggregate estimates in the literature is more likely than not to understate the actual costs of climate change.'

The Copenhagen Consensus

As part of the 2004 Copenhagen Consensus on the economics of global warming, Professor Robert O. Mendelsohn of Yale School of Forestry and Environmental Studies, stated that:

A series of studies on the impacts of climate change have systematically shown that the older literature overestimated climate damages by failing to allow for adaptation and for climate benefits (see Fankhauser et al. 1997; Mendelsohn and Newmann 1999; Tol 1999; Mendelsohn et al. 2000; Mendelsohn 2001;Maddison 2001; Tol 2002; Sohngen et al. 2002; Pearce 2003; Mendelsohn and Williams 2004). These new studies imply that impacts depend heavily upon initial temperatures (latitude). Countries in the polar region are likely to receive large benefits from warming, countries in the mid-latitudes will at first benefit and only begin to be harmed if temperatures rise above 2.5C (Mendelsohn et al. 2000). Only countries in the tropical and subtropical regions are likely to be harmed immediately by warming and be subject to the magnitudes of impacts first thought likely (Mendelsohn et al. 2000). Summing these regional impacts across the globe implies that warming benefits and damages will likely offset each other until warming passes 2.5C and even then it will be far smaller on net than originally thought (Mendelsohn and Williams 2004)."

The Stern Review

The Stern Review is a 2006 reportby the former Chief Economist and Senior Vice-President of the World Bank, Nicholas Stern, which predicts that climate change will have a serious impact on economic growth without mitigation.The report suggests that an investment of one percent of global GDP is required to mitigate the effects of climate change, with failure to do so risking a recession worth up to twenty percent of global GDP.

In the Stern Review, net monetised cost estimates of climate change were negative (i.e., net damages) for all global mean temperature increases. The Review has been criticized by some economists, saying that Stern did not consider costs past 2200, that he used an incorrect discount rate in his calculations, and that stopping or significantly slowing climate change will require deep emission cuts everywhere.

Some economists have supported Stern's approach, or argued that Stern's estimates are reasonable, even if the method by which he reached them is open to criticism. Research by Weitzman has suggested that structural uncertainty and low-probability high-impact risks are very important, and that "the influence on cost-benefit analysis of fat-tailed structural uncertainty about climate change, coupled with great unsureness about high-temperature damages, can outweigh the influence of discounting or anything else".

Criticism of aggregate costs

Some experts are critical of how economic studies aggregate costs of climate change damage.Schneider and Lane argue that because of the problems of one-metric aggregations, multiple metrics should be used to assess climate change damages.

Monetising aggregate costs of climate change often requires valuations of human welfare, the state of the environment, etc. This process is called using surrogate prices. The methodology and results of calculating surrogate prices has been described as 'problematical' by Ackerman.Using the example of the First and Second World Wars, Jaeger et al. argue that human suffering is 'incommensurable with GDP figures'.

Schneider and Lane point to the inadequacies of market-aggregation-only analysis, using Bangladesh as an example. Sea level rise due to climate change could reduce Bangladesh's GDP by about 80%, but this would only be equivalent to a reduction in global GDP of 0.1%. In a market-aggregation-only analysis, a loss of 0.1% global GDP would be described as being relatively insignificant. Schneider and Lane dispute this result, arguing that loss of life and biodiversity in Bangladesh are 'at least as important as aggregate market impacts'.

Distribution of impacts

According to the IPCC report: 'here is medium confidence that a warming of less than 2°C above 1990 levels would have net negative impacts on market sectors in many developing countries and net positive impacts on market sectors in many developed countries; and high confidence that above 2 to 3°C, there would be net negative impacts in many developed countries and additional negative impacts in many developing countries.'

Vulnerability to climate change is highly variable within individual countries. As a consequence, some population groups in developed countries are also highly vulnerable to a warming of less than 2°C.

Water

All IPCC regions show an overall net negative impact of climate change on water resources and freshwater ecosystems. Efforts to quantify the economic impacts of climate-related changes in water resources are hampered by a lack of data. Additionally, cost estimates are highly sensitive to different estimation methods and to different assumptions regarding how changes in water availability will be allocated across various types of water uses, e.g., between agricultural, urban, or in-stream uses.

Effects on agriculture

In the Summary for Policy Makers of the 4th Assessment Report, Working Group II of the Intergovernmental Panel on Climate Change states that: "Crop productivity is projected to increase slightly at mid- to high latitudes for local mean temperature increases of up to 1-3°C depending on the crop, and then decrease beyond that in some regions. At lower latitudes, especially seasonally dry and tropical regions, crop productivity is projected to decrease for even small local temperature increases (1-2°C), which would increase the risk of hunger. Globally, the potential for food production is projected to increase with increases in local average temperature over a range of 1-3°C, but above this it is projected to decrease."

Insurance

An industry very directly affected by the risks is the insurance industry; the number of major natural disasters has tripled since the 1960s, and insured losses increased fifteenfold in real terms (adjusted for inflation). According to one study, 35–40% of the worst catastrophes have been climate change related (ERM, 2002). Over the past three decades, the proportion of the global population affected by weather-related disasters has doubled in linear trend, rising from roughly 2% in 1975 to 4% in 2001 (ERM, 2002).

According to a 2005 report from the Association of British Insurers, limiting carbon emissions could avoid 80% of the projected additional annual cost of tropical cyclones by the 2080s. A June 2004 report by the Association of British Insurers declared "Climate change is not a remote issue for future generations to deal with. It is, in various forms, here already, impacting on insurers' businesses now." It noted that weather risks for households and property were already increasing by 2-4 % per year due to changing weather, and that claims for storm and flood damages in the UK had doubled to over £6 billion over the period 1998–2003, compared to the previous five years. The results are rising insurance premiums, and the risk that in some areas flood insurance will become unaffordable for some.

Financial institutions, including the world's two largest insurance companies, Munich Re and Swiss Re, warned in a 2002 study that "the increasing frequency of severe climatic events, coupled with social trends" could cost almost US$150 billion each year in the next decade.These costs would, through increased costs related to insurance and disaster relief, burden customers, taxpayers, and industry alike.

In the United States, insurance losses have also greatly increased. According to Choi and Fisher (2003) each 1% increase in annual precipitation could enlarge catastrophe loss by as much as 2.8%. Gross increases are mostly attributed to increased population and property values in vulnerable coastal areas, though there was also an increase in frequency of weather-related events like heavy rainfalls since the 1950s

Infrastructure

Roads, airport runways, railway lines and pipelines, (including oil pipelines, sewers, water mains etc) may require increased maintenance and renewal as they become subject to greater temperature variation and are exposed to weather that they were not designed for. Regions already adversely affected include areas of permafrost, which are subject to high levels of subsidence, resulting in buckling roads, sunken foundations, and severely cracked runways.

Investment

Venture capitalists and other investors have noted potential opportunities arising from global warming, as massive sums of money are needed for enhanced infrastructure as well as clean technologies that could help reduce emissions of global warming gases. As Joel Makower, a noted expert on business and the environment, has pointed out, "For all the handwringing over the negative bottom-line impacts of climate change for most companies, a handful of large corporate interests may come out winners, creating potentially profitable opportunities for forward-thinking investors." These include companies investing in clean energy technologies such as solar energy and wind power, but also companies in other sectors: agriculture (to produce biofuels as well as biobased plastics that supplant petroleum-based ones), information technology companies (producing switches, routers, and software intended to create a more efficient, "smart grid", chemical companies (producing "green chemistry" alternatives to petrochemicals), and producers of more efficient motors for aircraft, automobiles, and industrial use.

Migration

Some Pacific Ocean island nations, such as Tuvalu, are concerned about the possibility of an eventual evacuation, as flood defense may become economically inviable for them. Tuvalu already has an ad hoc agreement with New Zealand to allow phased relocation.

In the 1990s, a variety of estimates placed the number of environmental refugees at around 25 million. (Environmental refugees are not included in the official definition of refugees, which only includes migrants fleeing persecution.) The Intergovernmental Panel on Climate Change (IPCC), which advises the world’s governments under the auspices of the UN, estimated that 150 million environmental refugees will exist in the year 2050, due mainly to the effects of coastal flooding, shoreline erosion and agricultural disruption (150 million means 1.5% of 2050’s predicted 10 billion world population).

Northwest Passage



Melting Arctic ice may open the Northwest Passage in summer, which would cut 5,000 nautical miles (9,000 km) from shipping routes between Europe and Asia. This would be of particular relevance for supertankers which are too big to fit through the Panama Canal and currently have to go around the tip of South America. According to the Canadian Ice Service, the amount of ice in Canada's eastern Arctic Archipelago decreased by 15% between 1969 and 2004.

While the reduction of summer ice in the Arctic may be a boon to shipping, this same phenomenon threatens the Arctic ecosystem, most notably polar bears which depend on ice floes. Subsistence hunters such as the Inuit peoples will find their livelihoods and cultures increasingly threatened as the ecosystem changes due to global warming.

Development

The combined effects of global warming may impact particularly harshly on people and countries without the resources to mitigate those effects. This may slow economic development and poverty reduction, and make it harder to achieve the Millennium Development Goals.

In October 2004, the Working Group on Climate Change and Development, a coalition of development and environment NGOs, issued a report Up in Smoke on the effects of climate change on development. This report, and the July 2005 report Africa - Up in Smoke? predicted increased hunger and disease due to decreased rainfall and severe weather events, particularly in Africa. These are likely to have severe impacts on development for those affected.

At the same time, in developing countries, the poorest often live on flood plains, because it is the only available space, or fertile agricultural land. These settlements often lack infrastructure such as dykes and early warning systems. Poorer communities also tend to lack the insurance, savings or access to credit needed to recover from disasters.

Environmental

Assessing the economic value of ecosystems and biodiversity is difficult,but attempts have been made to do this. Stern presents the results of several integrated assessment models that include climate change impacts on ecosystems.

Non-monetised impacts of climate change on ecosystems and biodiversity are assessed in the IPCC report:of the species assessed so far, there is medium confidence (around 5/10 chance of being correct) that 20-30% will be at increased risk of extinction if global mean temperature increase exceeds 1.5-2.5 degrees Celsius (relative to the period 1980-1999). This temperature increase would be expected to have a predominantly negative impact on biodiversity and ecosystem goods and services, e.g. water and food supply.

Smith and Hitz looked at climate change impacts on terrestrial ecosystems.According to the paper, increased atmospheric concentrations of carbon dioxide - associated with the burning of fossil fuels - will be of some benefit to plant growth. Vegetation productivity is expected to peak then decline with increasing global mean temperature.

A 2004 study published in Nature estimates that between 15 and 37% of known plant and animal species will be 'committed to extinction' by 2050. Few of the terrestrial ecoregions on Earth could expect to be unaffected.

Water scarcity

Positive eustasy (sea-level rise) may contaminate groundwater, affecting drinking water and agriculture in coastal zones. Increased evaporation will reduce the effectiveness of reservoirs. Increased extreme weather means more water falls on hardened ground unable to absorb it, leading to flash floods instead of a replenishment of soil moisture or groundwater levels. In some areas, shrinking glaciers threaten the water supply. The availability of freshwater runoff from mountains for natural systems and human uses may also be impacted.

Higher temperatures will also increase the demand for water for the purposes of cooling and hydration.

Health

Currently, climate change contributes to increased early deaths and the burden of disease[. Climate change is expected to have a predominantly negative effect on human health, particularly in low-income countries . An example of a health benefit of climate change is fewer cold deaths. Some examples of negative health effects include:

* increased levels of malnutrition
* increased deaths, diseases, and injuries due to extreme weather events
* greater burden of diarrhoeal diseases

Some economists have included health outcomes in cost-benefit studies of climate change. These studies have several shortcomings; one is that they only cover a limited range of health outcomes, e.g., malaria, heat and cold deaths. In these studies, as is traditional in economics, the value of human mortality in poorer countries is judged to be lower than human mortality in richer countries. One study has suggested that replacing national mortality values with a global average would increase mortality costs by up to five times.

Heat and cold health effects

In temperate areas, warming of the climate is expected to bring some benefits, such as reduced numbers of deaths due to cold exposure. This benefit is expected to be outweighed by the negative effects of temperature rise, especially in developing countries.

Palutikof et al. calculate that in England and Wales for a 1 °C temperature rise the reduced deaths from cold outweigh the increased deaths from heat, resulting in a reduction in annual average mortality of 7000. However, in the United States, only 1000 people die from the cold each year, while twice that number die from the heat. The 2006 United States heat wave killed at least 225 people, with 163 of those in California. The central California valley, had six consecutive days of 110 degree-plus Fahrenheit temperatures.

The European heat wave of 2003 killed 22,000–35,000 people, based on normal mortality rates (Schär and Jendritzky, 2004). It can be said with 90% confidence that past human influence on climate was responsible for at least half the risk of the 2003 European summer heat-wave (Stott et al. 2004).

Spread of disease

Global warming is expected to extend the favourable zones for vectors conveying infectious disease such as malaria. In poorer countries, this may simply lead to higher incidence of such diseases. In richer countries, where such diseases have been eliminated or kept in check by vaccination, draining swamps and using pesticides, the consequences may be felt more in economic than health terms, if greater spending on preventative measures is required.

Contamination by sector and cost of reducing fossil fuel use

Reducing greenhouse gas emissions depends in part on lowering consumption of fossil fuels. The key challenge is that nearly all forms of economic activity rely on fossil fuel energy sources, from transportation fuel, electricity from coal-fired plants, industrial furnaces to home and office heating. Reducing emissions can be achieved through gains in efficiency - producing the same benefits with smaller amounts of fossil energy, or by displacing fossil sources with non- or low-emitting sources. Low emission renewable energy sources such as wind, solar and biomass still represent only a small fraction of total energy consumption. The scale of current fossil energy dependence poses a substantial challenge. Gaining energy efficiency typically requires up-front investment, such as adding insulation, replacing energy-inefficient devices and processes, or buying hybrid vehicles. Some such investments can pay for themselves in the savings on energy bills, and the economic case for choosing them depends on the payback period. If an upgrade's payback is better than the risk-free interest rate, economic theory predicts individuals will choose the higher return of making the efficiency investment. If current pricing is not leading to this outcome, the cost of fossil energy is not yet high enough to drive adoption of available efficiency gains. (Social science researchers Kurani and Turrentine reported in 2004 that consumers often fail to make choices that have favorable payback period. They attribute the "uneconomic" choices to risk aversion, weighing potential losses much higher than potential gains.)

Advocates of mitigating climate change hold that greenhouse gas emissions must carry a price, so the market can internalize the externality of the impact of their emission. This could take the form of a carbon tax or of emission caps, with a market created for trading emission permits, much as was done in the USA for sulfate emissions blamed for acid rain. Thus the economic impact of avoiding greenhouse gas emissions depends on how much consumption will have to be avoided, and how quickly the economy can incorporate efficiency gains.

Some pundits have criticized such attempts at calculating the costs of mitigating climate change by avoiding fossil fuel consumption, pointing out that the opportunity costs of avoiding consumption are not (and cannot) be calculated and are likely to be more important than the expected benefits .

Mitigation and adaptation

The costs of mitigating (reducing) global warming depend on a number of factors. One fundamental factor is the target level of atmospheric carbon dioxide: the lower the level, the sooner action must be taken if increases beyond the target level are to be avoided. The sooner action must be taken, the shorter the period over which costs must be spread, and the higher the absolute costs, as cheaper technologies which might emerge later are not yet available. A common target level (assumed by the United Kingdom) is 550ppm (current levels are around 380ppm, and rising at 2-3ppm per year). Signatories of the Kyoto Protocol committed themselves to targets that require lowering their national greenhouse gas emissions to a specified level relative to their actual 1990 emissions. During the target period for Kyoto of 2008-2012, many nations set targets to reach a small percentage below 1990 levels.

Another crucial factor in estimating the costs of climate change is the discount rate to apply. Normally a relatively high rate (e.g. 5%-10%) is applied, reflecting the cost of capital. However, where intergenerational issues involve potential irreversibilities such as climate change, a low discount rate (e.g. 1%-4%) may be applied. The difference is dramatic: at 4% (a typical rate for social issues), avoiding $1m worth of climate change damage in 100 years' time is valued at nearly $20,000 today (net present value), whereas at 8% it is valued at less than $500.

Another area for debate is the relationship between technological development and regulatory incentives: if regulation can induce substantial technological change, the costs of mitigation may be much lower.

The Kyoto Protocol

According to the IPCC report, 'notable achievements' of the UNFCCC and the Kyoto Protocol include:

* the establishment of a global response to the climate problem;
* the stimulation of an array of national policies;
* the creation of an international carbon market;
* the establishment of new institutional mechanisms that may provide the foundation for future mitigation efforts.

Significant differences exist between countries in meeting their Kyoto commitments. Collectively, industrial countries who ratified the treaty will probably meet their 2010 emission limitation targets.

The Kyoto Protocol was the first international agreement to set mandatory limits on greenhouse gas emissions. Kyoto's emission reduction targets have been criticised, with some saying they are too weak and others saying they are too strong. The IPCC report describes Kyoto's emission reduction targets as being 'modest', and to be more effective, 'future mitigation efforts would need to achieve deeper reductions covering a higher share of global emissions'.

Tol has stated that "the emissions targets agreed in the Kyoto Protocol are irreconcilable with economic rationality." Nordhaus and Boyer estimated that the present value of benefits from mitigation under the Kyoto Protocol would be $120 billion, far below the likely costs; "Other studies reach similar conclusions". Grubb has criticised cost-benefit analyses of this sort, arguing that they suffer from a number of problems.
Some economists view Kyoto as a useful first step in responding to climate change. Climate scientists O'Neill and Oppenheimer support Kyoto's targets, arguing that they are consistent with atmospheric CO2 stabilization at 450 ppm. A 450 ppm target could 'forestall the disintegration of WAIS, but is by no means certain, because additional warming would occur beyond 2100'.

Cost estimates

IPCC TAR (Synthesis Report) suggested values of $78 billion to $1141 billion annual mitigation costs, amounting to 0.2% to 3.5% of current world GDP (which is around $35 trillion), or 0.3% to 4.5% of GDP if borne by the richest nations alone. As economic growth is expected to continue, the percentage would fall. In terms of cost per tonne of carbon emission avoided, the range (for a target of 550ppm) is $18 to $80.

These cost estimates refer to reductions achieved through tradable emissions permits when those permits are given away to polluters. If the reductions are achieved through emission taxes or auctioned permits, and the revenue is used to reduce distortionary taxes, the TAR III synthesis report concludes that " on the existing tax structure, type of tax cuts, labour market conditions and method of recycling... it is possible that the economic benefits may exceed the costs of mitigation." Nordhaus and Boyer calculated that the present value cost of the Kyoto Protocol would be $800 billion to $1,500 billion if implemented as efficiently as possible. Richard Tol estimates that the net present value cost to be more than $2.5 trillion.

Azar and Schneider (2002) observe that global output in 1990 was around $20 trillion. If it grew steadily at 2.1 percent per annum it would be just short of $200 trillion by 2100. They thereby make the point that the calculated present value costs of mitigation would look smaller if scaled against 2100 output than if scaled against 1990 output. However, neither comparator is relevant to the question of whether the likely benefits from mitigation exceed the costs.

A 2008 study, not peer-reviewed, by the consulting company McKinsey Global Institute uses cost curve analysis to estimate that it is possible to stabilize global greenhouse gas concentrations at 450 to 500 ppm CO2-e with macroeconomic costs in the order of 0.6-1.4% of global GDP by 2030.

Lord Peter Levene, chairman of Lloyd's of London, said on 12 April 2007 that the threat of climate change must be an integral part of every company’s risk analysis.

Co-benefits

In addition to avoiding the costs of the business-as-usual scenario, mitigation actions can bring other benefits, depending on factors such as the technology used. These include, for example, the reduced economic impact from oil supply disruptions and/or price rises, if mitigation reduces oil dependence. This may be of particular benefit to non-oil-exporting developing countries, which suffer greater economic impact from oil price rises. Co-benefits from ending deforestation include protection of biodiversity, benefits for indigenous people, research and development possibilities, tourism, and some protection from extreme weather events. (Stern Review, page 280) Reducing greenhouse gas emissions also significantly reduces air pollution.

Optimal strategies for mitigation

Financial and technological strategies can have a major impact on reaching a particular target atmospheric greenhouse gas concentration.

* Carbon tax
* Carbon emissions trading
* A hybrid between a carbon tax and an emissions trading scheme, this can be thought of as an emissions trading scheme with a price cap, a price floor, or both. A price cap can be realized by governments being able to sell an unlimited amount extra permits at a given price (the price of the cap). A price floor can be realized by governments buying back permits if the price goes below the value of the floor, or by emitters paying a fee when they exercise the permit (so the effective carbon price is equal to the sum of the permit price and the exercise fee).
* Regulation
* Reducing the carbon intensity of energy via Nuclear power or Renewable Energy
* Energy efficiency

"No regrets" policies - notably reducing fossil fuel subsidies, which is predicted to increase growth whilst reducing CO2 emissions. Article 2 of the Kyoto Protocol specifies a progressive removal of subsidies and reform of taxes as a means of achieving reduction commitments.

McKibbin and Wilcoxen argue that a combination of long term carbon price signals and short terms caps on economic cost is needed to address both economic efficiency, equity sharing and political feasibility.

The Stern Review recommends adopting a quantative global stabilisation target range for the stock of greenhouse gases as a foundation for policy. It suggests that this target range would be likely to be somewhere between 450-550 ppm CO2-e. It also recommends a carbon price signal through the use of a carbon tax or emissions trading scheme.

Brink et al. (2005) showed that the costs of mitigation can be reduced by considering the inter-relationships of different greenhouse gas, and the differential impact that different technological decisions may have on their emissions.

Cost distribution

The costs and benefits of global warming are distributed quite unequally.

* low-lying countries' risk of floods
* many countries subject to increased drought are poor African countries
* ability of poor countries to mitigate / adapt (margin)
* GW increases variability of weather, which implies greater capital requirements for water storage systems, flood defenses, etc as well as individual requirements to cope with wider variation in weather patterns

The costs of mitigation may also be distributed unequally, both within and between countries. Wier et al. (2005) showed that carbon taxes, particularly direct taxes on households, are regressive (more so than VAT), suggesting that in order to maintain social acceptance the regressive effect needs to be compensated for either within the environmental tax structure, or in other parts of the tax system. Indirect taxes (on business) are less regressive, and petrol taxes are found to be progressive.

Inter-relationships between countries

Bastianoni et al. (2004) note the differences between methodologies for assigning responsibility for greenhouse gas emissions, which include the geographical approach, based on the IPCC guidelines for GHG inventory; the consumer responsibility approach, based on the Ecological Footprint methodology; and the Carbon Emission Added (CEA) approach, which resembles the accounting of a Value Added Tax. Different methodologies can produce quite different results in terms of responsibility for emissions, with consequent impact on policy.

Gradual change vs climate surprises

Baranzini et al. (2003) conclude that "(i) gradual, continuous uncertainty in the global warming process is likely to delay the adoption of abatement policies as found in previous studies, with respect to the standard CBA; however (ii) the possibility of climate catastrophes accelerates the implementation of these policies as their net discounted benefits increase significantly."

From http://en.wikipedia.org/