Arctic geoengineering

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Arctic sea ice coverage as of 2007 compared to 2005 and also compared to 1979-2000 average 2007 Arctic Sea Ice.jpg
Arctic sea ice coverage as of 2007 compared to 2005 and also compared to 1979-2000 average

Arctic geoengineering is a type of climate engineering in which polar climate systems are intentionally manipulated to reduce the undesired impacts of climate change. As a proposed solution to climate change, arctic geoengineering is relatively new and has not been implemented on a large scale. It is based on the principle that Arctic albedo plays a significant role in regulating the Earth's temperature and that there are large-scale engineering solutions that can help maintain Earth's hemispheric albedo. [1] According to researchers, projections of sea ice loss, when adjusted to account for recent rapid Arctic shrinkage, indicate that the Arctic will likely be free of summer sea ice sometime between 2059 and 2078. [2] Advocates for Arctic geoengineering believe that climate engineering methods can be used to prevent this from happening. [2] [ better source needed ]

Contents

Current proposed methods of arctic geoengineering include using sulfate aerosols to reflect sunlight,[ citation needed ] pumping water up to freeze on the surface, and using hollow glass microspheres to increase albedo. These methods are highly debated and have drawn criticism from some researchers, who argue that these methods may be ineffective, counterproductive, or produce unintended consequences. [3]

Background

History

The main goal of geoengineering from the 19th to mid 20th century was to create rain for use in irrigation or as offensive military action. [4] In 1965, the Johnson administration in the US issued a report that brought the focus of geoengineering to climate change. [4] Some of the early plans for geoengineering in the Arctic came from a 2006 NASA conference on the topic of "managing solar radiation" where astrophysicist Lowell Wood advanced the proposition of bombarding the Arctic stratosphere with sulfates to build up an ice sheet. [5] Other arctic geoengineering methods have since been proposed including the use of hollow glass microspheres. [6] [3]

Motivation

The Arctic's albedo plays a significant role in modulating the amount of solar radiation absorbed by Earth's surface. [1] With the loss of Arctic sea ice and the recent average darkening of Arctic albedo, the Arctic is less able to reflect solar radiation and thus cool Earth's surface. [1] Increased solar radiation causes higher surface temperatures and results in a positive feedback loop where arctic ice melts and albedo decreases further. [5] Such a feedback loop can push temperatures past a tipping point for certain irreversible climate domino effects. This is known as the ice-albedo feedback loop. [5]

Arctic sea ice retreat is further exacerbated by the release of methane, a greenhouse gas that is stored in arctic permafrost in the form of methane clathrate. [7] Excess methane being released into the atmosphere could result in another positive feedback loop in which temperatures continue to rise and more arctic sea ice melts. [8] At the current melting rate, if the global temperature rises 3°C above pre-industrial levels, the top permafrost layers of the arctic could melt at a rate of 30-85% and cause a climate emergency. [8] [ clarification needed ]The IPCC Fourth Assessment Report of 2007 states that "in some projections, Arctic late-summer sea ice disappears almost entirely by the latter part of the 21st century." [8] [ needs update ]However, arctic late-summer sea ice has since undergone significant retreat, reaching a record low in surface area in 2007 before recovering slightly in 2008. [8] [ needs update ] Climate engineering has been proposed for preventing or reversing tipping point events in the Arctic, in particular to halt the retreat of the sea ice. [9]

Goals

Proponents of arctic geoengineering believe that it may be one way of stabilizing carbon storage in the Arctic. [9] Arctic permafrost holds an estimated 1,700 billion metric tons of carbon, which is about 51 times the amount of carbon that was released globally as fossil fuel emissions in 2019. [10] Permafrost in the Northern Hemisphere also contains about twice as much carbon as the atmosphere, and arctic air temperature has increased at about six times more than the global average over the past few decades. [9] Arctic ecosystems are more sensitive to climate changes and could significantly contribute to global warming if arctic sea ice continues to melt at the current rate. [9] Preventing further ice loss is important for climate control, because the Arctic ice helps regulate global temperatures, by restraining strong greenhouse gasses like methane and carbon dioxide, which trap heat in Earth's atmosphere. [9]

Proponents believe that geoengineering techniques could be applied in the Arctic to protect existing sea ice and to promote further ice buildup by increasing ice production, reducing solar radiation from reaching the ice's surface, and slowing the melting of ice. [9] [11] The various proposed methods of recovering arctic ice vary in terms of cost and complexity, with some of the more intensive methods requiring significant economic investments and complex infrastructure systems. [11] One proposed method of increasing Earth's albedo is the injection of sulfate aerosols into the stratosphere. [11] Other proposed geoengineering methods to recover arctic ice include pumping seawater on top of existing arctic sea ice, and covering arctic sea ice with small hollow glass spheres. [11] [10]

Proposed methods

Stratospheric sulfate aerosols

The idea to inject sulfate aerosols into the stratosphere comes from simulating volcanic eruptions. [9] Sulfate particles found in the atmosphere help scatter sunlight, which increases the albedo, and in theory, produces a cooler climate on earth. [9]

Caldeira and Wood analyzed the effect of climate engineering in the Arctic using stratospheric sulfate aerosols. [12] He found that the Earth's average temperature change per unit albedo is unaffected by latitude because climate system feedbacks have a stronger presence in areas of high latitude; where less sunlight is reflected. [12]

Building thicker sea ice

It has been proposed to actively enhance the polar ice cap by spraying or pumping water onto the top of it which would build thicker sea ice. [13] [14] [15] A benefit of this method is that the increased salt content of the melting ice will tend to strengthen downwelling currents when the ice re-melts. [16] Some ice in the sea is frozen seawater. Other ice comes from glaciers, which come from compacted snow, and is thus fresh water ice.

A proposed method to build thicker sea ice is to use wind powered water pumps. These pumps contain a buoy that has a wind turbine attached to it, which functions to transfer the wind energy to power the pump. [17] The buoy also has a tank attached to it to store and release water as necessary. [17] In theory pumping 1.3 meters of water on top of the ice, at the right time, could increase the ice's thickness by 1.0 meter. [17] The goal of this pump is to increase ice thickness in a way that is energy efficient. [17] Pumps that use wind power to drive them have been successfully used in the South pole to increase ice thickness. [17]

Glass beads to increase albedo

Ice911, a non-profit organization whose goal is to reduce climate change, conducted an experiment in a lab. [6] They found that releasing reflective material on top of ice increased its albedo. [6] The reasoning behind this finding is that raising the ice's surfaces reflectivity increases its ability to reflect sunlight and therefore reduces the temperature on the ice's surface. [6] Of the materials used, Ice911 found glass was not only effective in raising the ice's albedo, but it was also financially feasible and environmentally friendly. [18] The team then moved forward and conducted field tests in California, Minnesota, and Alaska. [18] In all field testing locations, the albedo were increased in ice that had the glass beads poured on top of it compared to the ice that didn't have the glass beads added to its surface. [18] The findings indicate the glass beads placed on top of the ice increased the ice's reflectivity. [18]

Decreasing water salinity

Decreased salinity of ocean water causes it to become less dense, which in turn causes changing ocean currents. [19] [20] For this reason, it has been suggested [21] that locally influencing salinity and temperature of the Arctic Ocean by changing the ratio of Pacific and fluvial waters entering through the Bering Strait could play a key role in preserving Arctic sea ice. The purpose would be to create a relative increase of fresh water inflow from the Yukon River, while blocking (part) of the warm and saltier waters from the Pacific Ocean. Proposed geoengineering options include a dam [22] connecting St. Lawrence Island and a threshold under the narrow part of the strait.

Limitations and risks

Adverse weather conditions

Because geoengineering is a relatively new concept, there are no real studies on the ramifications of these new technologies and how they may affect weather patterns, ecosystems, and the climate in the long term. [23] Certain methods of arctic geoengineering, such as injecting sulfate aerosol into the stratosphere to reflect more sunlight, or marine cloud brightening, may trigger a chain of events that may be irreversible. [24] For the case of sulfur injection, such effects may include ocean acidification or crop failure due to either delayed precipitation patterns, or by reducing the amount of sunlight needed for them to grow. [25] The latter effects are similar for marine cloud brightening. The process involves using boats to increase sea water aerosol particles in the clouds closest to Earth's surface in order to reflect sunlight. [24] [26]

Rapid Ozone Depletion

Nobel laureate Paul Crutzen proposed a method of geoengineering in which emitting sulfates into the lower atmosphere would lead to global cooling and theoretically help tackle climate change. [27] The possible downside of this is that injecting sulfates into the stratosphere has the potential to lead to ozone depletion. [27] The process by which this works is that sulfate particles come into contact with atmospheric chlorine and chemically alter them. This reaction is estimated to have the possibility to deplete between one-third and one-half of the ozone layer over the Arctic if it goes into effect. [27] A proposed alternative to prevent this from happening is to swap out sulfates for calcite particles, the idea being that this is the material emitted into the atmosphere during a volcanic eruption. [28] [29] [10] There have not been any prototypes of such an experiment thus far, and while this method would not reverse the damage already done to the environment, it may aid in reducing some of the long-term potential damage.

Effectiveness of reflective particles

There are concerns surrounding the effectiveness of using glass, and other reflective particles, to increase albedo. [3] A study conducted by Webster and Warren found these particles actually increase the melting rates of sea ice. [3] Webster and Warren argue spreading glass over new ice works because the new ice is formed in the months were there is little sunlight, thus the effectiveness of the glass beads can not definitively be credited to the beads themselves. [3] Additionally, Webster and Warren argue the glass beads used in the study absorbed dark substances and overall decreased the albedo which could potentially lead to a faster melting rate of sea ice.

Related Research Articles

<span class="mw-page-title-main">Albedo</span> Ratio of how much light is reflected back from a body

Albedo is the fraction of sunlight that is diffusely reflected by a body. It is measured on a scale from 0 to 1. Surface albedo is defined as the ratio of radiosity Je to the irradiance Ee received by a surface. The proportion reflected is not only determined by properties of the surface itself, but also by the spectral and angular distribution of solar radiation reaching the Earth's surface. These factors vary with atmospheric composition, geographic location, and time.

<span class="mw-page-title-main">Causes of climate change</span> Effort to scientifically ascertain mechanisms responsible for recent global warming

The scientific community has been investigating the causes of climate change for decades. After thousands of studies, it came to a consensus, where it is "unequivocal that human influence has warmed the atmosphere, ocean and land since pre-industrial times." This consensus is supported by around 200 scientific organizations worldwide, The dominant role in this climate change has been played by the direct emissions of carbon dioxide from the burning of fossil fuels. Indirect CO2 emissions from land use change, and the emissions of methane, nitrous oxide and other greenhouse gases play major supporting roles.

<span class="mw-page-title-main">Cryosphere</span> Earths surface where water is frozen

The cryosphere is an all-encompassing term for the portions of Earth's surface where water is in solid form, including sea ice, lake ice, river ice, snow cover, glaciers, ice caps, ice sheets, and frozen ground. Thus, there is a wide overlap with the hydrosphere. The cryosphere is an integral part of the global climate system. It also has important feedbacks on the climate system. These feedbacks come from the cryosphere's influence on surface energy and moisture fluxes, clouds, the water cycle, atmospheric and oceanic circulation.

<span class="mw-page-title-main">Sulfate</span> Oxyanion with a central atom of sulfur surrounded by 4 oxygen atoms

The sulfate or sulphate ion is a polyatomic anion with the empirical formula SO2−4. Salts, acid derivatives, and peroxides of sulfate are widely used in industry. Sulfates occur widely in everyday life. Sulfates are salts of sulfuric acid and many are prepared from that acid.

<span class="mw-page-title-main">Global dimming</span> Reduction in the amount of sunlight reaching Earths surface

Global dimming is a decline in the amount of sunlight reaching the Earth's surface. It is caused by atmospheric particulate matter, predominantly sulfate aerosols, which are components of air pollution. Global dimming was observed soon after the first systematic measurements of solar irradiance began in the 1950s. This weakening of visible sunlight proceeded at the rate of 4–5% per decade until the 1980s. During these years, air pollution increased due to post-war industrialization. Solar activity did not vary more than the usual during this period.

<span class="mw-page-title-main">Cloud condensation nuclei</span> Small particles on which water vapor condenses

Cloud condensation nuclei (CCNs), also known as cloud seeds, are small particles typically 0.2 μm, or one hundredth the size of a cloud droplet. CCNs are a unique subset of aerosols in the atmosphere on which water vapour condenses. This can affect the radiative properties of clouds and the overall atmosphere. Water vapour requires a non-gaseous surface to make the transition to a liquid; this process is called condensation.

This glossary of climate change is a list of definitions of terms and concepts relevant to climate change, global warming, and related topics.

Planetary engineering is the development and application of technology for the purpose of influencing the environment of a planet. Planetary engineering encompasses a variety of methods such as terraforming, seeding, and geoengineering.

Climate engineering is an umbrella term for both carbon dioxide removal and solar radiation modification, when applied at a planetary scale. However, these two processes have very different characteristics. For this reason, the Intergovernmental Panel on Climate Change no longer uses this overarching term. Carbon dioxide removal approaches are part of climate change mitigation. Solar radiation modification is reflecting some sunlight back to space. Some publications place passive radiative cooling into the climate engineering category. This technology increases the Earth's thermal emittance. The media tends to use climate engineering also for other technologies such as glacier stabilization, ocean liming, and iron fertilization of oceans. The latter would modify carbon sequestration processes that take place in oceans.

<span class="mw-page-title-main">Mikhail Budyko</span> Soviet-Russian climatologist (1920 – 2001)

Mikhail Ivanovich Budyko was a Soviet and Russian climatologist and one of the founders of physical climatology. He pioneered studies on global climate and calculated temperature of Earth considering simple physical model of equilibrium in which the incoming solar radiation absorbed by the Earth's system is balanced by the energy re-radiated to space as thermal energy.

<span class="mw-page-title-main">Climate change in the Arctic</span> Impacts of climate change on the Arctic

Due to climate change in the Arctic, this polar region is expected to become "profoundly different" by 2050. The speed of change is "among the highest in the world", with the rate of warming being 3-4 times faster than the global average. This warming has already resulted in the profound Arctic sea ice decline, the accelerating melting of the Greenland ice sheet and the thawing of the permafrost landscape. These ongoing transformations are expected to be irreversible for centuries or even millennia.

Polar meteorology is the study of the atmosphere of Earth's polar regions. Surface temperature inversion is typical of polar environments and leads to the katabatic wind phenomenon. The vertical temperature structure of polar environments tends to be more complex than in mid-latitude or tropical climates.

<span class="mw-page-title-main">Tipping points in the climate system</span> Large and possibly irreversible changes in the climate system

In climate science, a tipping point is a critical threshold that, when crossed, leads to large, accelerating and often irreversible changes in the climate system. If tipping points are crossed, they are likely to have severe impacts on human society and may accelerate global warming. Tipping behavior is found across the climate system, for example in ice sheets, mountain glaciers, circulation patterns in the ocean, in ecosystems, and the atmosphere. Examples of tipping points include thawing permafrost, which will release methane, a powerful greenhouse gas, or melting ice sheets and glaciers reducing Earth's albedo, which would warm the planet faster. Thawing permafrost is a threat multiplier because it holds roughly twice as much carbon as the amount currently circulating in the atmosphere.

This is a list of climate change topics.

<span class="mw-page-title-main">Arctic methane emissions</span> Release of methane from seas and soils in permafrost regions of the Arctic

Arctic methane release is the release of methane from Arctic ocean waters as well as from soils in permafrost regions of the Arctic. While it is a long-term natural process, methane release is exacerbated by global warming. This results in a positive climate change feedback, as methane is a powerful greenhouse gas. The Arctic region is one of many natural sources of methane. Climate change could accelerate methane release in the Arctic, due to the release of methane from existing stores, and from methanogenesis in rotting biomass. When permafrost thaws as a consequence of warming, large amounts of organic material can become available for methanogenesis and may ultimately be released as methane.

<span class="mw-page-title-main">Solar radiation modification</span> Approaches to limit global warming by increasing the reflection of sunlight back to space

Solar radiation modification (SRM), or solar geoengineering, refers to a range of approaches to limit global warming by increasing the amount of sunlight that the atmosphere reflects back to space or by reducing the trapping of outgoing thermal radiation. Among the multiple potential approaches, stratospheric aerosol injection is the most-studied, followed by marine cloud brightening. SRM could be a temporary measure to limit climate-change impacts while greenhouse gas emissions are reduced and carbon dioxide is removed, but would not be a substitute for reducing emissions.

<span class="mw-page-title-main">Marine cloud brightening</span> Proposed cloud-seeding technique

Marine cloud brightening also known as marine cloud seeding and marine cloud engineering is a proposed solar radiation management climate engineering technique that would make clouds brighter, reflecting a small fraction of incoming sunlight back into space in order to offset anthropogenic global warming. Along with stratospheric aerosol injection, it is one of the two solar radiation management methods that may most feasibly have a substantial climate impact. The intention is that increasing the Earth's albedo, in combination with greenhouse gas emissions reduction, carbon dioxide removal, and adaptation, would reduce climate change and its risks to people and the environment. If implemented, the cooling effect is expected to be felt rapidly and to be reversible on fairly short time scales. However, technical barriers remain to large-scale marine cloud brightening. There are also risks with such modification of complex climate systems.

<span class="mw-page-title-main">Polar seas</span> Collective term for the Arctic Ocean and the southern part of the Southern Ocean

Polar seas is a collective term for the Arctic Ocean and the southern part of the Southern Ocean. In the coldest years, sea ice can cover around 13 percent of the Earth's total surface at its maximum, but out of phase in the two hemispheres. The polar seas contain a huge biome with many organisms.

<span class="mw-page-title-main">Stratospheric aerosol injection</span> Putting particles in the stratosphere to reflect sunlight to limit global heating

Stratospheric aerosol injection is a proposed method of solar geoengineering to reduce global warming. This would introduce aerosols into the stratosphere to create a cooling effect via global dimming and increased albedo, which occurs naturally from volcanic winter. It appears that stratospheric aerosol injection, at a moderate intensity, could counter most changes to temperature and precipitation, take effect rapidly, have low direct implementation costs, and be reversible in its direct climatic effects. The Intergovernmental Panel on Climate Change concludes that it "is the most-researched [solar geoengineering] method that it could limit warming to below 1.5 °C (2.7 °F)." However, like other solar geoengineering approaches, stratospheric aerosol injection would do so imperfectly and other effects are possible, particularly if used in a suboptimal manner.

<span class="mw-page-title-main">Climate change feedbacks</span> Feedback related to climate change

Climate change feedbacks are natural processes which impact how much global temperatures will increase for a given amount of greenhouse gas emissions. Positive feedbacks amplify global warming while negative feedbacks diminish it. Feedbacks influence both the amount of greenhouse gases in the atmosphere and the amount of temperature change that happens in response. While emissions are the forcing that causes climate change, feedbacks combine to control climate sensitivity to that forcing.

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