Geoengineering

Geoengineering

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The concept of Geoengineering (or climate engineering, climate remediation, and climate intervention ) refers to the deliberate large-scale engineering and manipulation of the planetary environment to combat or counteract anthropogenic changes in atmospheric chemistry
The Intergovernmental Panel on Climate Change
Intergovernmental Panel on Climate Change
The Intergovernmental Panel on Climate Change is a scientific intergovernmental body which provides comprehensive assessments of current scientific, technical and socio-economic information worldwide about the risk of climate change caused by human activity, its potential environmental and...

 concluded in 2007 that geoengineering options, such as ocean fertilization to remove CO2 from the atmosphere
Atmosphere
An atmosphere is a layer of gases that may surround a material body of sufficient mass, and that is held in place by the gravity of the body. An atmosphere may be retained for a longer duration, if the gravity is high and the atmosphere's temperature is low...

, remained largely unproven. It was judged that reliable cost estimates for geoengineering had not yet been published.

Geoengineering accompanies mitigation
Mitigation of global warming
Climate change mitigation is action to decrease the intensity of radiative forcing in order to reduce the potential effects of global warming. Mitigation is distinguished from adaptation to global warming, which involves acting to tolerate the effects of global warming...

 and adaptation
Adaptation to global warming
Adaptation to global warming and climate change is a response to climate change that seeks to reduce the vulnerability of natural and human systems to climate change effects. Even if emissions are stabilized relatively soon, climate change and its effects will last many years, and adaptation will...

 to form a three-stranded 'MAG' approach to tackling global warming
Global warming
Global warming refers to the rising average temperature of Earth's atmosphere and oceans and its projected continuation. In the last 100 years, Earth's average surface temperature increased by about with about two thirds of the increase occurring over just the last three decades...

, notably advocated by the Institution of Mechanical Engineers
Institution of Mechanical Engineers
The Institution of Mechanical Engineers is the British engineering society based in central London, representing mechanical engineering. It is licensed by the Engineering Council UK to assess candidates for inclusion on ECUK's Register of professional Engineers...

. Some geoengineering techniques are based on carbon dioxide removal. These techniques seek to reduce greenhouse gases in the atmosphere directly. These include direct methods (e.g. carbon dioxide air capture
Carbon dioxide air capture
Carbon dioxide removal methods refers to a number of technologies which reduce the levels of carbon dioxide in the atmosphere. Among such technologies are bio-energy with carbon capture and storage, biochar, direct air capture, ocean fertilization and enhanced weathering.CDR is a different...

) and indirect methods (e.g. ocean iron fertilization). These techniques can be regarded as mitigation of global warming
Mitigation of global warming
Climate change mitigation is action to decrease the intensity of radiative forcing in order to reduce the potential effects of global warming. Mitigation is distinguished from adaptation to global warming, which involves acting to tolerate the effects of global warming...

.

Alternatively, solar radiation management
Solar radiation management
Solar radiation management projects are a type of geoengineering which seek to reflect sunlight and thus reduce global warming. Examples include the creation of stratospheric sulfur aerosols. They do not reduce greenhouse gas concentrations in the atmosphere, and thus do not address problems...

 techniques (SRM), 'Reflective Approaches' (RA),
do not reduce greenhouse gas concentrations, and can only address the warming effects of carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

 and other gases; they cannot address problems such as ocean acidification
Ocean acidification
Ocean acidification is the name given to the ongoing decrease in the pH and increase in acidity of the Earth's oceans, caused by the uptake of anthropogenic carbon dioxide from the atmosphere....

, which are expected as a result of rising carbon dioxide levels.
Examples of proposed solar radiation management techniques include the production of stratospheric sulfur aerosols
Stratospheric sulfur aerosols (geoengineering)
The ability of stratospheric sulfate aerosols to create a global dimming effect has made them a possible candidate for use in geoengineering projects to limit the effect and impact of climate change due to rising levels of greenhouse gases...

, which was suggested by Paul Crutzen, space mirrors
Space mirror (anti-global warming measure)
The use of space mirrors as an anti-global warming measure is one of a series of proposals made to the United States government for reducing global warming....

, and cloud reflectivity enhancement
Cloud reflectivity enhancement
Cloud reflectivity enhancement is also known as 'marine cloud brightening' or 'cloud whitening' on low cloud. An opposite scheme exists to reduce the reflectivity of higher, colder cirrus clouds. It is a geoengineering technique that works by solar radiation management. By modifying the...

. Most techniques have at least some side effects.

To date, no large-scale geoengineering projects have been undertaken. Some limited tree planting and cool roof
Cool roof
Cool roofs are the roofs that can deliver high solar reflectance and high thermal emittance...

 projects are already underway, and ocean iron fertilization
Iron fertilization
Iron fertilization is the intentional introduction of iron to the upper ocean to stimulate a phytoplankton bloom. This is intended to enhance biological productivity, which can benefit the marine food chain and remove carbon dioxide from the atmosphere. Iron is a trace element necessary for...

 is at an advanced stage of research, with small-scale research trials and global modelling having been completed. Field research
Field research
Field research is the collection of raw data in natural settings. It helps to reveal the habits and habitats of various organisms present in their natural surroundings...

 into sulfur aerosols has also started. Some commentators have suggested that consideration of geoengineering presents a moral hazard
Moral hazard
In economic theory, moral hazard refers to a situation in which a party makes a decision about how much risk to take, while another party bears the costs if things go badly, and the party insulated from risk behaves differently from how it would if it were fully exposed to the risk.Moral hazard...

 because it threatens to reduce the political and popular pressure for emissions reduction. Scientists do not typically suggest geoengineering as an alternative to emissions control
Emissions control
Emissions control may refer to:* EMCON, military state of readiness.* Technology involved in vehicle emissions control* Regulation of air pollution via emission standards...

, but rather an accompanying strategy. Reviews of geoengineering techniques have emphasised that they are not substitutes for emission controls and have identified potentially stronger and weaker schemes.

Definition


Geoengineering is the idea of applying planetary engineering
Planetary engineering
Planetary engineering is the application of technology for the purpose of influencing the global properties of a planet. The goal of this theoretical task is usually to make other worlds habitable for life....

 to Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

. Geoengineering would involve the deliberate modification of Earth's environment
Natural environment
The natural environment encompasses all living and non-living things occurring naturally on Earth or some region thereof. It is an environment that encompasses the interaction of all living species....

 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
Climate change
Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average...

. However, others define it more narrowly as nature-integrated engineering projects. The term geoengineering is distinct from environmental damage and accidental anthropogenic
Anthropogenic
Human impact on the environment or anthropogenic impact on the environment includes impacts on biophysical environments, biodiversity and other resources. The term anthropogenic designates an effect or object resulting from human activity. The term was first used in the technical sense by Russian...

 climate change, which are side-effects of human activity, rather than an intended consequence. The global extraction of hydrocarbon
Hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls....

s from the sub-surface 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


Several notable organisations have investigated geoengineering with a view to evaluating its potential, including, NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

, the Royal Society
Royal Society
The Royal Society of London for Improving Natural Knowledge, known simply as the Royal Society, is a learned society for science, and is possibly the oldest such society in existence. Founded in November 1660, it was granted a Royal Charter by King Charles II as the "Royal Society of London"...

, the Institute of Mechanical Engineers, and the UK Parliament,. The Asilomar International Conference on Climate Intervention Technologies
Asilomar international conference on climate intervention technologies
The Asilomar International Conference on Climate Intervention Technologies was a conference developed by Dr. Margaret Leinen of the Climate Response Fund and chaired by Dr. Michael MacCracken of the Climate Institute. The conference took place in March 2010 and the recommendations were published in...

 was convened to identify and develop risk reduction guidelines for climate intervention experimentation.

The major environmental organisations such as Friends of the Earth
Friends of the Earth
Friends of the Earth International is an international network of environmental organizations in 76 countries.FOEI is assisted by a small secretariat which provides support for the network and its agreed major campaigns...

 and Greenpeace
Greenpeace
Greenpeace is a non-governmental environmental organization with offices in over forty countries and with an international coordinating body in Amsterdam, The Netherlands...

 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
Greenhouse gas
A greenhouse gas is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect. The primary greenhouse gases in the Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone...

 emissions.

Proposed strategies


Several geoengineering strategies have been proposed. IPCC documents detail several notable proposals. These fall into two main categories: solar radiation management
Solar radiation management
Solar radiation management projects are a type of geoengineering which seek to reflect sunlight and thus reduce global warming. Examples include the creation of stratospheric sulfur aerosols. They do not reduce greenhouse gas concentrations in the atmosphere, and thus do not address problems...

 and carbon dioxide removal. However, other proposals exist.

Solar radiation management


Solar radiation management (SRM) projects seek to reduce the net incoming short-wave (ultra-violet and visible) solar radiation received, by deflecting sunlight, or by increasing the reflectivity (albedo) of the
atmosphere. They do not reduce greenhouse gas
Greenhouse gas
A greenhouse gas is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect. The primary greenhouse gases in the Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone...

 concentrations in the atmosphere
Atmosphere
An atmosphere is a layer of gases that may surround a material body of sufficient mass, and that is held in place by the gravity of the body. An atmosphere may be retained for a longer duration, if the gravity is high and the atmosphere's temperature is low...

, and thus do not address problems such as ocean acidification
Ocean acidification
Ocean acidification is the name given to the ongoing decrease in the pH and increase in acidity of the Earth's oceans, caused by the uptake of anthropogenic carbon dioxide from the atmosphere....

 caused by these gases. Solar radiation management projects often have the advantage of speed. While greenhouse gas remediation
Greenhouse gas remediation
Greenhouse gas remediation projects are a type of geoengineering and seek to remove greenhouse gases from the atmosphere, and thus tackle the root cause of global warming. These techniques either directly remove greenhouse gases, or alternatively seek to influence natural processes to remove...

 offers a comprehensive possible solution to climate change, it does not give instant results; for that, solar radiation management is required.

SRM methods may be:
  • Surface-based (land or ocean albedo modification); eg. Cool roof
    Cool roof
    Cool roofs are the roofs that can deliver high solar reflectance and high thermal emittance...

    —using pale-coloured roofing and paving materials.
  • Troposphere-based (cloud modification methods, etc.); Creating reflective aerosols, such as stratospheric sulfur aerosols
    Stratospheric sulfur aerosols (geoengineering)
    The ability of stratospheric sulfate aerosols to create a global dimming effect has made them a possible candidate for use in geoengineering projects to limit the effect and impact of climate change due to rising levels of greenhouse gases...

    , Cloud whitening – using fine sea water spray to whiten clouds and increase cloud reflectivity.
  • Upper atmosphere-based (tropopause and above, ie, stratosphere, mesosphere);
  • Space-based: Eg. Space sunshade—obstructing solar radiation with space-based mirrors or other structures.

Carbon dioxide removal



Carbon dioxide removal 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
Carbon capture and storage
Carbon capture and storage , alternatively referred to as carbon capture and sequestration, is a technology to prevent large quantities of from being released into the atmosphere from the use of fossil fuel in power generation and other industries. It is often regarded as a means of mitigating...

 and carbon sequestration projects, and may not be considered to be geoengineering by all commentators. Techniques in this category include:
  • Creating biochar
    Biochar
    Biochar or terra preta is charcoal created by pyrolysis of biomass. Biochar is under investigation as an approach to carbon sequestration via bio-energy with carbon capture and storage. Biochar thus has the potential to help mitigate climate change, via carbon sequestration...

     (anaerobic charcoal) and burying it to create terra preta
    Terra preta
    Terra preta is a type of very dark, fertile anthropogenic soil found in the Amazon Basin. Terra preta owes its name to its very high charcoal content, and was indeed made by adding a mixture of charcoal, bone, and manure to the otherwise relatively infertile Amazonian soil, and stays there for...

  • Bio-energy with carbon capture and storage
    Bio-energy with carbon capture and storage
    Bio-energy with carbon capture and storage is a greenhouse gas mitigation technology which produces negative carbon emissions by combining biomass use with geologic carbon capture and storage....

     to remove carbon and simultaneously provide energy
  • Carbon air capture to remove carbon dioxide
    Carbon dioxide
    Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

     from ambient air
  • Ocean nourishment
    Ocean Nourishment
    Ocean Nourishment is a type of geoengineering based on the purposeful introduction of nutrients to the upper ocean to increase marine food production and to sequester carbon dioxide from the atmosphere. Fertilization can also potentially create sulfur aerosols which reduce the rate of global warming...

     including Iron fertilisation of the oceans



Heat transport


The use of vertical ocean pipes to mix cooler deep water and warmer surface water has been proposed. This technology has also been suggested for the disruption of hurricanes by Bill Gates
Bill Gates
William Henry "Bill" Gates III is an American business magnate, investor, philanthropist, and author. Gates is the former CEO and current chairman of Microsoft, the software company he founded with Paul Allen...

 and others in a recent patent application
Patent application
A patent application is a request pending at a patent office for the grant of a patent for the invention described and claimed by that application. An application consists of a description of the invention , together with official forms and correspondence relating to the application...

. Modification of hurricanes may be considered weather modification rather than geoengineering, depending on the definition used.

Tipping points and positive feedback



It is argued that climate change
Climate change
Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average...

 has already, or is soon to have passed one or more tipping point
Tipping point (climatology)
A climate tipping point is a point when global climate changes from one stable state to another stable state, in a similar manner to a wine glass tipping over. After the tipping point has been passed, a transition to a new state occurs...

s where 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
Positive feedback
Positive feedback is a process in which the effects of a small disturbance on a system include an increase in the magnitude of the perturbation. That is, A produces more of B which in turn produces more of A. In contrast, a system that responds to a perturbation in a way that reduces its effect is...

 effects, such as the collapse of Arctic sea ice triggering the release of methane
Methane
Methane is a chemical compound with the chemical formula . It is the simplest alkane, the principal component of natural gas, and probably the most abundant organic compound on earth. The relative abundance of methane makes it an attractive fuel...

 from permafrost
Permafrost
In geology, permafrost, cryotic soil or permafrost soil is soil at or below the freezing point of water for two or more years. Ice is not always present, as may be in the case of nonporous bedrock, but it frequently occurs and it may be in amounts exceeding the potential hydraulic saturation of...

 in Siberia
Siberia
Siberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...

. The "nightmare scenario" is that a domino effect
Domino effect
The domino effect is a chain reaction that occurs when a small change causes a similar change nearby, which then will cause another similar change, and so on in linear sequence. The term is best known as a mechanical effect, and is used as an analogy to a falling row of dominoes...

 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 feedback
Positive feedback
Positive feedback is a process in which the effects of a small disturbance on a system include an increase in the magnitude of the perturbation. That is, A produces more of B which in turn produces more of A. In contrast, a system that responds to a perturbation in a way that reduces its effect is...

s 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
Mitigation of global warming
Climate change mitigation is action to decrease the intensity of radiative forcing in order to reduce the potential effects of global warming. Mitigation is distinguished from adaptation to global warming, which involves acting to tolerate the effects of 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
Atmosphere
An atmosphere is a layer of gases that may surround a material body of sufficient mass, and that is held in place by the gravity of the body. An atmosphere may be retained for a longer duration, if the gravity is high and the atmosphere's temperature is low...

 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 cool roof
Cool roof
Cool roofs are the roofs that can deliver high solar reflectance and high thermal emittance...

 techniques, can be achieved at little or no cost, and may even offer a financial payback. IPCC (2007) concluded that reliable cost estimates for geoengineering options had not been published. In general, solar radiation management techniques are substantially cheaper than are carbon dioxide removal techniques.

Ethics and Responsibility


Climate engineering would represent a large-scale, intentional effort to modify the environment, which differ from inadvertent climate change through activities such as burning fossil fuels. Intentional climate change is viewed very differently from a moral standpoint. This raises questions of whether we as humans have the right to change the climate. The selection of a globally-agreed target temperature is a significant problem in any geoengineering governance
Governance
Governance is the act of governing. It relates to decisions that define expectations, grant power, or verify performance. It consists of either a separate process or part of management or leadership processes...

 regime, as different countries or interest groups may seek different global temperatures

Solar radiation management is an incomplete solution to global warming. The possible option of geoengineering may reduce incentives to reduce emissions of greenhouse gases. It is argued that geoengineering could be used to ‘buy time’ before drastic climate change happens, allowing mitigation and adaptation measures more time to be implemented and work. But the opposition points out that there are issues regarding the interference this causes with actual efforts for climate change, creating an unnecessary distraction.

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
Kyoto Protocol
The Kyoto Protocol is a protocol to the United Nations Framework Convention on Climate Change , aimed at fighting global warming...

 demonstrate the practical difficulties of achieving carbon dioxide emissions reduction by the agreement of the international community
International community
The international community is a term used in international relations to refer to all peoples, cultures and governments of the world or to a group of them. The term is used to imply the existence of common duties and obligations between them...

. However, others point to support for geoengineering proposals among think tanks with a history of 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.

Geoenginering poses several challenges in the context of governance because of issues of power and jurisdiction. Geoengineering as a climate change solution differs from other mitigation and adaptation strategies. Unlike a carbon trading system that would be focused on participation from multiple parties along with transparency, monitoring measures and compliance procedures; this is not necessarily required by geoengineering. Bengtsson (2006) argues that “the artificial release of sulphate aerosols is a commitment of at least several hundred years”. This highlights the importance for a political framework that is sustainable enough to contain a multilateral commitment over such a long period and yet is flexible as the techniques innovate through time. There are many controversies surrounding this topic and hence, geoengineering has been made into a very political issue. Most discussions and debates are not about which geoengineering technique is better than the other, or which one is more economically and socially feasible. Discussions are broadly on who will have control over the deployment of geoengineering and under what governance regime the deployment can be monitored and supervised. This is especially important due to the regional variability of the effects of many geoengineering techniques, benefiting some countries while damaging others. The challenge posed by geoengineering is not how to get countries to do it. It is to address the fundamental question of who should decide whether and how geoengineering should be attempted – a problem of governance.

Risks and criticisms



Various criticisms have been made of geoengineering. Some commentators appear fundamentally opposed. Groups such as ETC Group
ETC Group
ETC Group is an international organization dedicated to "the conservation and sustainable advancement of cultural and ecological diversity and human rights." The full legal name is Action Group on Erosion, Technology and Concentration...

  and individuals such as Raymond Pierrehumbert
Raymond Pierrehumbert
Raymond T. Pierrehumbert is Louis Block Professor in Geophysical Sciences at the University of Chicago. He was a lead author on the IPCC Third Assessment Report, and a co-author of the National Research Council report on abrupt climate change...

 have called for a moratorium on geoengineering techniques.

Ineffectiveness


The effectiveness of the schemes proposed may fall short of predictions. In ocean iron fertilization
Iron fertilization
Iron fertilization is the intentional introduction of iron to the upper ocean to stimulate a phytoplankton bloom. This is intended to enhance biological productivity, which can benefit the marine food chain and remove carbon dioxide from the atmosphere. Iron is a trace element necessary for...

, for example, the amount of carbon dioxide removed from the atmosphere
Atmosphere
An atmosphere is a layer of gases that may surround a material body of sufficient mass, and that is held in place by the gravity of the body. An atmosphere may be retained for a longer duration, if the gravity is high and the atmosphere's temperature is low...

 may be much lower than predicted, as carbon taken up by plankton
Plankton
Plankton are any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. That is, plankton are defined by their ecological niche rather than phylogenetic or taxonomic classification...

 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
Atmosphere
An atmosphere is a layer of gases that may surround a material body of sufficient mass, and that is held in place by the gravity of the body. An atmosphere may be retained for a longer duration, if the gravity is high and the atmosphere's temperature is low...

 may control global warming
Global warming
Global warming refers to the rising average temperature of Earth's atmosphere and oceans and its projected continuation. In the last 100 years, Earth's average surface temperature increased by about with about two thirds of the increase occurring over just the last three decades...

, but do not reduce other effects from these gases, such as ocean acidification
Ocean acidification
Ocean acidification is the name given to the ongoing decrease in the pH and increase in acidity of the Earth's oceans, caused by the uptake of anthropogenic carbon dioxide from the atmosphere....

. While 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



The full effects of various geoengineering schemes are not well understood. Matthews et al. compared geoengineering to a number of previous environmental interventions and concluded that "Given our current level of understanding of the climate system, it is likely that the result of at least some geoengineering efforts would follow previous ecological examples where increased human intervention has led to an overall increase in negative environmental consequences."

Performance of the systems may become ineffective, unpredictable or unstable as a result of external events, such as volcanic eruptions
Volcanic Eruptions
Volcanic Eruptions is a company owned by Crispin Glover. The company produces and issues Glover's work: It has released two films to date, What Is It? and its sequel, It is Fine! EVERYTHING IS FINE . Its current plans include releasing the final film in the trilogy titled It Is Mine...

, phytoplankton
Phytoplankton
Phytoplankton are the autotrophic component of the plankton community. The name comes from the Greek words φυτόν , meaning "plant", and πλαγκτός , meaning "wanderer" or "drifter". Most phytoplankton are too small to be individually seen with the unaided eye...

 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 point
Tipping point
In sociology, a tipping point is the event of a previously rare phenomenon becoming rapidly and dramatically more common. The phrase was coined in its sociological use by Morton Grodzins, by analogy with the fact in physics that adding a small amount of weight to a balanced object can cause it to...

s, 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
Litter
Litter consists of waste products such as containers, papers, wrappers or faeces which have been disposed of without consent. Litter can also be used as a verb...

, which may be harmful to wildlife
Wildlife
Wildlife includes all non-domesticated plants, animals and other organisms. Domesticating wild plant and animal species for human benefit has occurred many times all over the planet, and has a major impact on the environment, both positive and negative....

.

Ozone depletion
Ozone depletion
Ozone depletion describes two distinct but related phenomena observed since the late 1970s: a steady decline of about 4% per decade in the total volume of ozone in Earth's stratosphere , and a much larger springtime decrease in stratospheric ozone over Earth's polar regions. The latter phenomenon...

 is a risk of some geoengineering techniques, notably those involving sulfur
Sulfur
Sulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...

 delivery into the stratosphere
Stratosphere
The stratosphere is the second major layer of Earth's atmosphere, just above the troposphere, and below the mesosphere. It is stratified in temperature, with warmer layers higher up and cooler layers farther down. This is in contrast to the troposphere near the Earth's surface, which is cooler...

.

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
Arctic
The Arctic is a region located at the northern-most part of the Earth. The Arctic consists of the Arctic Ocean and parts of Canada, Russia, Greenland, the United States, Norway, Sweden, Finland, and Iceland. The Arctic region consists of a vast, ice-covered ocean, surrounded by treeless permafrost...

. 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
Chaos theory
Chaos theory is a field of study in mathematics, with applications in several disciplines including physics, economics, biology, and philosophy. Chaos theory studies the behavior of dynamical systems that are highly sensitive to initial conditions, an effect which is popularly referred to as the...

 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


Geoengineering research began as a war tactic in the 1940s for the US and the Soviet Union during the Cold War. During the Vietnam War, the US used geoengineering to flood certain areas. Then in 1976, 85 countries signed the U.N. Convention on the Prohibition of Military or Any Other Hostile Use of Environmental Modification Techniques.

The Environmental Modification Convention generally prohibits weaponising geoengineering techniques. However, this does not eliminate the risk. Geoengineering techniques may serve as weapons 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
Operation Popeye
Operation Popeye was a US military cloud seeding operation during the Vietnam war to extend the monsoon season over Laos, specifically areas of the Ho Chi Minh Trail...

). 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.

Carnegie
Carnegie
Carnegie may refer to:*Andrew Carnegie, Scottish-American industrialist and philanthropist, for whom many entries on this page are named*Dale Carnegie, motivational speaker and author*David Carnegie , Scottish-Swedish industrialist...

’s Ken Caldeira
Ken Caldeira
Ken Caldeira is an atmospheric scientist who works at the Carnegie Institution for Science's . He researches ocean acidification, climate effects of trees, intentional climate modification, and interactions in the global Carbon cycle/climate system...

 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
Sky
The sky is the part of the atmosphere or outer space visible from the surface of any astronomical object. It is difficult to define precisely for several reasons. During daylight, the sky of Earth has the appearance of a pale blue surface because the air scatters the sunlight. The sky is sometimes...

 from aerosol
Aerosol
Technically, an aerosol is a suspension of fine solid particles or liquid droplets in a gas. Examples are clouds, and air pollution such as smog and smoke. In general conversation, aerosol usually refers to an aerosol spray can or the output of such a can...

 projects, notably a hazing of blue skies and a change in the appearance of sunset
Sunset
Sunset or sundown is the daily disappearance of the Sun below the horizon in the west as a result of Earth's rotation.The time of sunset is defined in astronomy as the moment the trailing edge of the Sun's disk disappears below the horizon in the west...

s. Aerosols may affect the formation of clouds, especially cirrus cloud
Cirrus cloud
Cirrus clouds are atmospheric clouds generally characterized by thin, wispy strands, giving them their name from the Latin word cirrus meaning a ringlet or curling lock of hair...

s.

Moral hazard


The existence of such techniques may reduce the political and social impetus to reduce carbon emissions.. The issue of moral hazard
Moral hazard
In economic theory, moral hazard refers to a situation in which a party makes a decision about how much risk to take, while another party bears the costs if things go badly, and the party insulated from risk behaves differently from how it would if it were fully exposed to the risk.Moral hazard...

 means that many environmental groups and campaigners are reluctant to advocate geoengineering for fear of reducing the imperative to cut greenhouse gas
Greenhouse gas
A greenhouse gas is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect. The primary greenhouse gases in the Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone...

 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
Attribution of recent climate change
Attribution of recent climate change is the effort to scientifically ascertain mechanisms responsible for recent changes observed in the Earth's climate...

. Because geoengineering is a form of controlling the risks associated with global warming, it leads to a moral hazard
Moral hazard
In economic theory, moral hazard refers to a situation in which a party makes a decision about how much risk to take, while another party bears the costs if things go badly, and the party insulated from risk behaves differently from how it would if it were fully exposed to the risk.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
David Keith (scientist)
David W. Keith is a Canadian environmental scientist. He is the former director of the Institute for Sustainable Energy, Environment and Economy Energy and Environmental Systems Group at the University of Calgary. Keith is noted for his work in carbon dioxide air capture, and has been featured on...

 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
Auric Goldfinger
Auric Goldfinger is a fictional character and the main antagonist in the James Bond film and novel Goldfinger. His first name, Auric, is an adjective meaning of gold...

). David Victor suggests that geoengineering is within the reach of any individual who has a small fraction of the bank account of Bill Gates
Bill Gates
William Henry "Bill" Gates III is an American business magnate, investor, philanthropist, and author. Gates is the former CEO and current chairman of Microsoft, the software company he founded with Paul Allen...

, 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
Atmosphere
An atmosphere is a layer of gases that may surround a material body of sufficient mass, and that is held in place by the gravity of the body. An atmosphere may be retained for a longer duration, if the gravity is high and the atmosphere's temperature is low...

. Opposition to some early schemes has been intense, with respected environmental groups campaigning against them.

Rapid warming if stopped


If solar radiation management
Solar radiation management
Solar radiation management projects are a type of geoengineering which seek to reflect sunlight and thus reduce global warming. Examples include the creation of stratospheric sulfur aerosols. They do not reduce greenhouse gas concentrations in the atmosphere, and thus do not address problems...

 were to abruptly stop, the climate would rapidly warm. This would cause a sudden rise in global temperatures towards levels which would have existed without the use of the geoengineering technique. The rapid rise in temperature may lead to more severe consequences than a gradual rise of the same magnitude.

Implementation issues


There is no general consensus that geoengineering is safe, appropriate or effective, for the reasons listed above. 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
Coal
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...

 and oil
Petroleum
Petroleum or crude oil is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights and other liquid organic compounds, that are found in geologic formations beneath the Earth's surface. Petroleum is recovered mostly through oil drilling...

 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
Research and development
The phrase research and development , according to the Organization for Economic Co-operation and Development, refers to "creative work undertaken on a systematic basis in order to increase the stock of knowledge, including knowledge of man, culture and society, and the use of this stock of...

 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
Albedo
Albedo , or reflection coefficient, is the diffuse reflectivity or reflecting power of a surface. It is defined as the ratio of reflected radiation from the surface to incident radiation upon it...

 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


Most of what is known about the suggested techniques is based on laboratory experiments, observations of natural phenomena and on computer modelling techniques. Some geoengineering schemes employ methods that have analogues in natural phenomena such as stratospheric sulfur aerosols
Stratospheric sulfur aerosols
Stratospheric sulfur aerosols are sulfur-rich particles which exist in the stratosphere region of the Earth's atmosphere. The layer of the atmosphere in which they exist is known as the Junge layer, or simply the stratospheric aerosol layer. These particles consist of a mixture of sulfuric acid...

 and cloud condensation nuclei
Cloud condensation nuclei
Cloud condensation nuclei or CCNs are small particles typically 0.2 µm, or 1/100 th the size of a cloud droplet ) about which cloud droplets coalesce. Water requires a non-gaseous surface to make the transition from a vapour to a liquid. In the atmosphere, this surface presents itself as tiny...

. As such, studies about the efficacy of these schemes can draw on information already available from other research, such as that following the 1991 eruption of Mount Pinatubo
Mount Pinatubo
Mount Pinatubo is an active stratovolcano located on the island of Luzon, near the tripoint of the Philippine provinces of Zambales, Tarlac, and Pampanga. It is located in the Tri-Cabusilan Mountain range separating the west coast of Luzon from the central plains, and is west of the dormant and...

. However, comparative evaluation of the relative merits of each technology is complicated, especially given modelling uncertainties and the early stage of engineering development of many geoengineering schemes.

Reports into geoengineering have also been published in the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 by the Institution of Mechanical Engineers
Institution of Mechanical Engineers
The Institution of Mechanical Engineers is the British engineering society based in central London, representing mechanical engineering. It is licensed by the Engineering Council UK to assess candidates for inclusion on ECUK's Register of professional Engineers...

 and the Royal Society
Royal Society
The Royal Society of London for Improving Natural Knowledge, known simply as the Royal Society, is a learned society for science, and is possibly the oldest such society in existence. Founded in November 1660, it was granted a Royal Charter by King Charles II as the "Royal Society of London"...

. The IMechE report examined a small subset of proposed schemes (air capture, urban albedo and algal-based capture schemes), and its main conclusions were that geoengineering should be researched and trialled at the small scale alongside a wider decarbonisation of the economy.

The Royal Society review examined a wide range of geoengineering schemes and evaluated them in terms of effectiveness, affordability, timeliness and safety (assigning qualitative estimates in each assessment). Similarly to Lenton and Vaughan, the report divided schemes into "carbon dioxide removal" (CDR) and "solar radiation management" (SRM) approaches that respectively address longwave and shortwave radiation. The key recommendations of the report were that "Parties to the UNFCCC should make increased efforts towards mitigating and adapting to climate change, and in particular to agreeing to global emissions reductions", and that "[nothing] now known about geoengineering options gives any reason to diminish these efforts". Nonetheless, the report also recommended that "research and development of geoengineering options should be undertaken to investigate whether low risk methods can be made available if it becomes necessary to reduce the rate of warming this century".

In a 2009 review study, Lenton and Vaughan evaluated a range of geoengineering schemes from those that sequester from the atmosphere and decrease longwave radiation trapping, to those that decrease the Earth's receipt of shortwave radiation
Shortwave radiation
Shortwave radiation is a term used to describe radiant energy with wavelengths in the visible , near-ultraviolet , and near-infrared spectra....

. In order to permit a comparison of disparate techniques, they used a common evaluation for each scheme based on its effect on net radiative forcing. As such, the review examined the scientific plausibility of schemes rather than the practical considerations such as engineering feasibility or economic cost. Lenton and Vaughan found that "[air] capture and storage shows the greatest potential, combined with afforestation, reforestation and bio-char production", and noted that "other suggestions that have received considerable media attention, in particular “ocean pipes” appear to be ineffective". They concluded that "[climate] geoengineering is best considered as a potential complement to the mitigation of emissions, rather than as an alternative to it".

See also


  • Arctic geoengineering
    Arctic geoengineering
    Temperatures in the Arctic region have tended to increase more rapidly than the global average. Projections of sea ice loss that are adjusted to take account of recent rapid Arctic shrinkage suggest that the Arctic will likely be free of summer sea ice sometime between 2059 and 2078...

  • Carbon sink
  • Convention on Biological Diversity
    Convention on Biological Diversity
    The Convention on Biological Diversity , known informally as the Biodiversity Convention, is an international legally binding treaty...

  • ETC Group
    ETC Group
    ETC Group is an international organization dedicated to "the conservation and sustainable advancement of cultural and ecological diversity and human rights." The full legal name is Action Group on Erosion, Technology and Concentration...

  • Five Ways to Save the World
    Five ways to save the world
    Five Ways to Save the World is a British documentary film on environmental issues related to climate change, released in 2006. The film was made by Karen O'Connor, for the big screen and was shot in the English language to reach an international audience...

  • List of geoengineering topics
  • List of proposed geoengineering projects
  • Planetary Engineering
    Planetary engineering
    Planetary engineering is the application of technology for the purpose of influencing the global properties of a planet. The goal of this theoretical task is usually to make other worlds habitable for life....

  • Terraforming
    Terraforming
    Terraforming of a planet, moon, or other body is the hypothetical process of deliberately modifying its atmosphere, temperature, surface topography or ecology to be similar to those of Earth, in order to make it habitable by terrestrial organisms.The term is sometimes used more generally as a...

  • Virgin Earth Challenge
    Virgin Earth Challenge
    The Virgin Earth Challenge is a competition offering a $25 million prize for whoever can demonstrate a commercially viable design which results in the permanent removal of greenhouse gases out of the Earth's atmosphere, so as to contribute materially to avoid global warming...

  • Weather control
    Weather control
    Weather control is the act of manipulating or altering certain aspects of the environment to produce desirable changes in weather. Weather control can have the goal of preventing damaging weather, such as hurricanes or tornadoes, from occurring; of causing beneficial weather, such as rainfall in...


Further reading

--Abstract only, full article requires payment.
  • Granger Morgan, Katharine Ricke (2010). An Opinion Piece for IRGC. Cooling the Earth Through Solar Radiation Management: The need for research and an approach to its governance. ISBN 978-2-9700672-8-3

External links