Green chemistry

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Green_chemistry

Green chemistry, similar to sustainable chemistry or circular chemistry, is an area of chemistry and chemical engineering focused on the design of products and processes that minimize or eliminate the use and generation of hazardous substances. While environmental chemistry focuses on the effects of polluting chemicals on nature, green chemistry focuses on the environmental impact of chemistry, including lowering consumption of nonrenewable resources and technological approaches for preventing pollution.

The overarching goals of green chemistry—namely, more resource-efficient and inherently safer design of molecules, materials, products, and processes—can be pursued in a wide range of contexts.

Definition

Green chemistry (also called sustainable chemistry) is the design of chemical products and processes that reduce or eliminate the use and generation of hazardous substances. The concept integrates pollution-prevention and process-intensification approaches at laboratory and industrial scales to improve resource efficiency and minimize waste and risk across the life cycle of chemicals and materials.

History

Green chemistry evolved and emerged from a variety of existing ideas and research efforts (such as Pollution Prevention, atom economy and catalysis) in the period leading up to the 1990s, in the context of increasing attention to problems of chemical pollution and resource depletion. The development of green chemistry in Europe and the United States was proceeded by a shift in environmental problem-solving strategies: a movement from command and control regulation and mandated lowering of industrial emissions at the "end of the pipe," toward the broad interdisciplinary concept of prevention of pollution through the innovative design of production technologies themselves. The narrower set of concepts later recognized and re-named as green chemistry coalesced in the mid- to late-1990s, along with broader adoption of the new term in the Academic literature (which prevailed over earlier competing terms such as "clean" and "sustainable" chemistry).

In the United States, the Environmental Protection Agency played a significant supporting role in evolving green chemistry out of its earlier pollution prevention programs, funding, and cooperative coordination with industry. At the same time in the United Kingdom, researchers at the University of York, who used the term "clean technology" in the early 1990s, contributed to the establishment of the Green Chemistry Network within the Royal Society of Chemistry, and the launch of the journal Green Chemistry. In 1991, in the Netherlands, a special issue called 'green chemistry' [groene chemie] was published in Chemisch Magazine. In the Dutch context, the umbrella term green chemistry was associated with the exploitation of biomass as a renewable feedstock.

Principles

In 1998, Paul Anastas (who then directed the Green Chemistry Program at the US EPA) and John C. Warner (then of Polaroid Corporation) published a set of principles to guide the practice of green chemistry. The twelve principles address a range of ways to lower the environmental and health impacts of chemical production, and also indicate research priorities for the development of green chemistry technologies.

The principles cover such concepts as:

• the design of processes to maximize the amount of raw material that ends up in the product;
• the use of renewable material feedstocks and energy sources;
• the use of safe, environmentally benign substances, including solvents, whenever possible;
• the design of energy efficient processes;
• avoiding the production of waste, which is viewed as the ideal form of waste management.

The twelve principles of green chemistry are:

1. Prevention: Preventing waste is better than treating or cleaning up waste after it is created.
2. Atom economy: Synthetic methods should try to maximize the incorporation of all materials used in the process into the final product. This means that less waste will be generated as a result.
3. Less hazardous chemical syntheses: Synthetic methods should avoid using or generating substances toxic to humans and/or the environment.
4. Designing safer chemicals: Chemical products should be designed to achieve their desired function while being as non-toxic as possible.
5. Safer solvents and auxiliaries: Auxiliary substances should be avoided wherever possible, and as non-hazardous as possible when they must be used.
6. Design for energy efficiency: Energy requirements should be minimized, and processes should be conducted at ambient temperature and pressure whenever possible.
7. Use of renewable feedstocks: Whenever it is practical to do so, renewable feedstocks or raw materials are preferable to non-renewable ones.
8. Reduce derivatives: Unnecessary generation of derivatives—such as the use of protecting groups—should be minimized or avoided if possible; such steps require additional reagents and may generate additional waste.
9. Catalysis: Catalytic reagents that can be used in small quantities to repeat a reaction are superior to stoichiometric reagents (ones that are consumed in a reaction).
10. Design for degradation: Chemical products should be designed so that they do not pollute the environment; when their function is complete, they should break down into non-harmful products.
11. Real-time analysis for pollution prevention: Analytical methodologies need to be further developed to permit real-time, in-process monitoring and control before hazardous substances form.
12. Inherently safer chemistry for accident prevention: Whenever possible, the substances in a process, and the forms of those substances, should be chosen to minimize risks such as explosions, fires, and accidental releases.

Trends

Attempts are being made not only to quantify the greenness of a chemical process but also to factor in other variables such as chemical yield, the price of reaction components, safety in handling chemicals, hardware demands, energy profile and ease of product workup and purification. In one quantitative study, the reduction of nitrobenzene to aniline receives 64 points out of 100 marking it as an acceptable synthesis overall whereas a synthesis of an amide using HMDS is only described as adequate with a combined 32 points.

Green-chemistry methods are applied to the development and manufacture of nanomaterials, with attention to life-cycle impacts and potential nanotoxicity.

Examples

Green solvents

Main article: Green solvent

The major application of solvents in human activities is in paints and coatings (46% of usage). Smaller volume applications include cleaning, de-greasing, adhesives, and in chemical synthesis. Traditional solvents are often toxic or are chlorinated. Green solvents, on the other hand, are generally less harmful to health and the environment and preferably more sustainable. Ideally, solvents would be derived from renewable resources and biodegrade to innocuous, often a naturally occurring product. However, the manufacture of solvents from biomass can be more harmful to the environment than making the same solvents from fossil fuels. Thus the environmental impact of solvent manufacture must be considered when a solvent is being selected for a product or process. Another factor to consider is the fate of the solvent after use. If the solvent is being used in an enclosed situation where solvent collection and recycling is feasible, then the energy cost and environmental harm associated with recycling should be considered; in such a situation water, which is energy-intensive to purify, may not be the greenest choice. On the other hand, a solvent contained in a consumer product is likely to be released into the environment upon use, and therefore the environmental impact of the solvent itself is more important than the energy cost and impact of solvent recycling; in such a case water is very likely to be a green choice. In short, the impact of the entire lifetime of the solvent, from cradle to grave (or cradle to cradle if recycled) must be considered. Thus the most comprehensive definition of a green solvent is the following: "a green solvent is the solvent that makes a product or process have the least environmental impact over its entire life cycle."

By definition, then, a solvent might be green for one application (because it results in less environmental harm than any other solvent that could be used for that application) and yet not be a green solvent for a different application. A classic example is water, which is a very green solvent for consumer products such as toilet bowl cleaner but is not a green solvent for the manufacture of polytetrafluoroethylene. For the production of that polymer, the use of water as solvent requires the addition of perfluorinated surfactants which are highly persistent. Instead, supercritical carbon dioxide seems to be the greenest solvent for that application because it performs well without any surfactant. In summary, no solvent can be declared to be a "green solvent" unless the declaration is limited to a specific application.

Synthetic techniques

Novel or enhanced synthetic techniques can often provide improved environmental performance or enable better adherence to the principles of green chemistry. For example, the 2005 Nobel Prize for Chemistry was awarded to Yves Chauvin, Robert H. Grubbs and Richard R. Schrock, for the development of the metathesis method in organic synthesis, with explicit reference to its contribution to green chemistry and "smarter production." A 2005 review identified three key developments in green chemistry in the field of organic synthesis: use of supercritical carbon dioxide as green solvent, aqueous hydrogen peroxide for clean oxidations and the use of hydrogen in asymmetric synthesis. Some further examples of applied green chemistry are supercritical water oxidation, on water reactions, and dry media reactions.

Bioengineering is also seen as a promising technique for achieving green chemistry goals. A number of important process chemicals can be synthesized in engineered organisms, such as shikimate, a Tamiflu precursor which is fermented by Roche in bacteria. Click chemistry is often cited as a style of chemical synthesis that is consistent with the goals of green chemistry. The concept of 'green pharmacy' has recently been articulated based on similar principles.

Carbon dioxide as blowing agent

In 1996, Dow Chemical won the 1996 Greener Reaction Conditions award for their 100% carbon dioxide blowing agent for polystyrene foam production. Polystyrene foam is a common material used in packing and food transportation. Seven hundred million pounds are produced each year in the United States alone. Traditionally, CFC and other ozone-depleting chemicals were used in the production process of the foam sheets, presenting a serious environmental hazard. Flammable, explosive, and, in some cases toxic hydrocarbons have also been used as CFC replacements, but they present their own problems. Dow Chemical discovered that supercritical carbon dioxide works equally as well as a blowing agent, without the need for hazardous substances, allowing the polystyrene to be more easily recycled. The CO₂ used in the process is reused from other industries, so the net carbon released from the process is zero.

Hydrazine

Addressing principle #2 is the peroxide process for producing hydrazine without cogenerating salt. Hydrazine is traditionally produced by the Olin Raschig process from sodium hypochlorite (the active ingredient in many bleaches) and ammonia. The net reaction produces one equivalent of sodium chloride for every equivalent of the targeted product hydrazine:

NaOCl + 2 NH₃ → H₂N-NH₂ + NaCl + H₂O

In the greener peroxide process hydrogen peroxide is employed as the oxidant and the side product is water. The net conversion follows:

2 NH₃ + H₂O₂ → H₂N-NH₂ + 2 H₂O

Addressing principle #4, this process does not require auxiliary extracting solvents. Methyl ethyl ketone is used as a carrier for the hydrazine, the intermediate ketazine phase separates from the reaction mixture, facilitating workup without the need of an extracting solvent.

1,3-Propanediol

Addressing principle #7 is a green route to 1,3-propanediol, which is traditionally generated from petrochemical precursors. It can be produced from renewable precursors via the bioseparation of 1,3-propanediol using a genetically modified strain of E. coli. This diol is used to make new polyesters for the manufacture of carpets.

Lactide

Lactide

In 2002, Cargill Dow (now NatureWorks) won the Greener Reaction Conditions Award for their improved method for polymerization of polylactic acid. Unfortunately, lactide-base polymers do not perform well and the project was discontinued by Dow soon after the award. Lactic acid is produced by fermenting corn and converted to lactide, the cyclic dimer ester of lactic acid using an efficient, tin-catalyzed cyclization. The L,L-lactide enantiomer is isolated by distillation and polymerized in the melt to make a crystallizable polymer, which has some applications including textiles and apparel, cutlery, and food packaging. The NatureWorks PLA process substitutes renewable materials for petroleum feedstocks, doesn't require the use of hazardous organic solvents typical in other PLA processes, and results in a high-quality polymer that is recyclable and compostable.

Carpet tile backings

In 2003 Shaw Industries selected a combination of polyolefin resins as the base polymer of choice for EcoWorx due to the low toxicity of its feedstocks, superior adhesion properties, dimensional stability, and its ability to be recycled. The EcoWorx compound also had to be designed to be compatible with nylon carpet fiber. Although EcoWorx may be recovered from any fiber type, nylon-6 provides a significant advantage. Polyolefins are compatible with known nylon-6 depolymerization methods. PVC interferes with those processes. Nylon-6 chemistry is well-known and not addressed in first-generation production. From its inception, EcoWorx met all of the design criteria necessary to satisfy the needs of the marketplace from a performance, health, and environmental standpoint. Research indicated that separation of the fiber and backing through elutriation, grinding, and air separation proved to be the best way to recover the face and backing components, but an infrastructure for returning postconsumer EcoWorx to the elutriation process was necessary. Research also indicated that the postconsumer carpet tile had a positive economic value at the end of its useful life. EcoWorx is recognized by MBDC as a certified cradle-to-cradle design.

Transesterification of fats

Trans and cis fatty acids

In 2005, Archer Daniels Midland (ADM) and Novozymes won the Greener Synthetic Pathways Award for their enzyme interesterification process. In response to the U.S. Food and Drug Administration (FDA) mandated labeling of trans-fats on nutritional information by January 1, 2006, Novozymes and ADM worked together to develop a clean, enzymatic process for the interesterification of oils and fats by interchanging saturated and unsaturated fatty acids. The result is commercially viable products without trans-fats. In addition to the human health benefits of eliminating trans-fats, the process has reduced the use of toxic chemicals and water, prevents vast amounts of byproducts, and reduces the amount of fats and oils wasted.

Bio-succinic acid

In 2011, the Outstanding Green Chemistry Accomplishments by a Small Business Award went to BioAmber Inc. for integrated production and downstream applications of bio-based succinic acid. Succinic acid is a platform chemical that is an important starting material in the formulations of everyday products. Traditionally, succinic acid is produced from petroleum-based feedstocks. Bio Amber has developed process and technology that produces succinic acid from the fermentation of renewable feedstocks at a lower cost and lower energy expenditure than the petroleum equivalent while sequestering CO₂ rather than emitting it. However, lower prices of oil precipitated the company into bankruptcy  and bio-sourced succinic acid is now barely made.

Laboratory chemicals

Several laboratory chemicals are controversial from the perspective of Green chemistry. The Massachusetts Institute of Technology created a "Green" Alternatives Wizard to help identify alternatives. Ethidium bromide, xylene, mercury, and formaldehyde have been identified as "worst offenders" which have alternatives. Solvents in particular make a large contribution to the environmental impact of chemical manufacturing and there is a growing focus on introducing Greener solvents into the earliest stage of development of these processes: laboratory-scale reaction and purification methods. In the Pharmaceutical Industry, both GSK and Pfizer have published Solvent Selection Guides for their Drug Discovery chemists.

Legislation

The EU

In 2007, The EU put into place the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) program, which requires companies to provide data showing that their products are safe. This regulation (1907/2006) ensures not only the assessment of the chemicals' hazards as well as risks during their uses but also includes measures for banning or restricting/authorizing uses of specific substances. ECHA, the EU Chemicals Agency in Helsinki, is implementing the regulation whereas the enforcement lies with the EU member states.

United States

The United States formed the Environmental Protection Agency (EPA) in 1970 to protect human and environmental health by creating and enforcing environmental regulation. Green chemistry builds on the EPA's goals by encouraging chemists and engineers to design chemicals, processes, and products that avoid the creation of toxins and waste.

The U.S. law that governs the majority of industrial chemicals (excluding pesticides, foods, and pharmaceuticals) is the Toxic Substances Control Act (TSCA) of 1976. Examining the role of regulatory programs in shaping the development of green chemistry in the United States, analysts have revealed structural flaws and long-standing weaknesses in TSCA; for example, a 2006 report to the California Legislature concludes that TSCA has produced a domestic chemicals market that discounts the hazardous properties of chemicals relative to their function, price, and performance. Scholars have argued that such market conditions represent a key barrier to the scientific, technical, and commercial success of green chemistry in the U.S., and fundamental policy changes are needed to correct these weaknesses.

Passed in 1990, the Pollution Prevention Act helped foster new approaches for dealing with pollution by preventing environmental problems before they happen.

Green chemistry grew in popularity in the United States after the Pollution Prevention Act of 1990 was passed. This Act declared that pollution should be lowered by improving designs and products rather than treatment and disposal. These regulations encouraged chemists to reimagine pollution and research ways to limit the toxins in the atmosphere. In 1991, the EPA Office of Pollution Prevention and Toxics created a research grant program encouraging the research and recreation of chemical products and processes to limit the impact on the environment and human health. The EPA hosts The Green Chemistry Challenge each year to incentivize the economic and environmental benefits of developing and utilizing green chemistry.

In 2008, the State of California approved two laws aiming to encourage green chemistry, launching the California Green Chemistry Initiative. One of these statutes required California's Department of Toxic Substances Control (DTSC) to develop new regulations to prioritize "chemicals of concern" and promote the substitution of hazardous chemicals with safer alternatives. The resulting regulations took effect in 2013, initiating DTSC's Safer Consumer Products Program.

Scientific journals specialized in green chemistry

• Green Chemistry (RSC)
• Green Chemistry Letters and Reviews (Open Access) (Taylor & Francis)
• ChemSusChem (Wiley)
• ACS Sustainable Chemistry & Engineering (ACS)

Contested definition

There are ambiguities in the definition of green chemistry and how it is understood among broader science, policy, and business communities. Even within chemistry, researchers have used the term "green chemistry" to describe a range of work independently of the framework put forward by Anastas and Warner (i.e., the 12 principles). While not all uses of the term are legitimate (see greenwashing), many are, and the authoritative status of any single definition is uncertain. More broadly, the idea of green chemistry can easily be linked (or confused) with related concepts like green engineering, environmental design, or sustainability in general. Green chemistry's complexity and multifaceted nature makes it difficult to devise clear and simple metrics. As a result, "what is green" is often open to debate.

Climate inertia

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Climate_inertia 

Societal elements of inertia work to prevent abrupt shifts within pathways of greenhouse gas emissions, while physical inertia of the Earth system acts to delay the surface temperature response.

Climate inertia or climate change inertia is the phenomenon by which a planet's climate system shows a resistance or slowness to deviate away from a given dynamic state. It can accompany stability and other effects of feedback within complex systems, and includes the inertia exhibited by physical movements of matter and exchanges of energy. The term is a colloquialism used to encompass and loosely describe a set of interactions that extend the timescales around climate sensitivity. Inertia has been associated with the drivers of, and the responses to, climate change.

Increasing fossil-fuel carbon emissions are a primary inertial driver of change to Earth's climate during recent decades, and have risen along with the collective socioeconomic inertia of its 8 billion human inhabitants. Many system components have exhibited inertial responses to this driver, also known as a forcing. The rate of rise in global surface temperature (GST) has especially been resisted by 1) the thermal inertia of the planet's surface, primarily its ocean, and 2) inertial behavior within its carbon cycle feedback. Various other biogeochemical feedbacks have contributed further resiliency. Energy stored in the ocean following the inertial responses principally determines near-term irreversible change known as climate commitment.

Earth's inertial responses are important because they provide the planet's diversity of life and its human civilization further time to adapt to an acceptable degree of planetary change. However, unadaptable change like that accompanying some tipping points may only be avoidable with early understanding and mitigation of the risk of such dangerous outcomes. This is because inertia also delays much surface warming unless and until action is taken to rapidly reduce emissions. An aim of Integrated assessment modelling, summarized for example as Shared Socioeconomic Pathways (SSP), is to explore Earth system risks that accompany large inertia and uncertainty in the trajectory of human drivers of change.

Inertial timescales

Response times to climate forcing

Earth System Component	Time Constant (years)	Response Modes
Atmosphere
Water Vapor and Clouds	10−2-10	EC, WC
Trace Gases	10−1-108	CC
Hydrosphere
Ocean Mixed Layer	10−1-10	EC, WC, CC
Deep Ocean	10-103	EC, CC
Lithosphere
Land Surface and Soils	10−1-102	EC, WC, CC
Subterranean Sediments	104-109	CC
Cryosphere
Glaciers	10−1-10	EC, WC
Sea Ice	10−1-10	EC, WC
Ice Sheets	103-106	EC, WC
Biosphere
Upper Marine	10−1-102	CC
Terrestrial	10−1-102	WC, CC
EC=Energy Cycle WC=Water Cycle  CC=Carbon Cycle

The paleoclimate record shows that Earth's climate system has evolved along various pathways and with multiple timescales. Its relatively stable states which can persist for many millennia have been interrupted by short to long transitional periods of relative instability. Studies of climate sensitivity and inertia are concerned with quantifying the most basic manner in which a sustained forcing perturbation will cause the system to deviate within or initially away from its relatively stable state of the present Holocene epoch.

"Time constants" are useful metrics for summarizing the first-order (linear) impacts of the various inertial phenomena within both simple and complex systems. They quantify the time after which 63% of a full output response occurs following the step change of an input. They are observed from data or can be estimated from numerical simulation or a lumped system analysis. In climate science these methods can be applied to Earth's energy cycle, water cycle, carbon cycle and elsewhere. For example, heat transport and storage in the ocean, cryosphere, land and atmosphere are elements within a lumped thermal analysis. Response times to radiative forcing via the atmosphere typically increase with depth below the surface.

Inertial time constants indicate a base rate for forced changes, but lengthy values provide no guarantee of long-term system evolution along a smooth pathway. Numerous higher-order tipping elements having various trigger thresholds and transition timescales have been identified within Earth's present state. Such events might precipitate a nonlinear rearrangement of internal energy flows along with more rapid shifts in climate and/or other systems at regional to global scale.

Climate response time

The response of global surface temperature (GST) to a step-like doubling of the atmospheric CO₂ concentration, and its resultant forcing, is defined as the Equilibrium Climate Sensitivity (ECS). The ECS response extends over short and long timescales, however the main time constant associated with ECS has been identified by Jule Charney, James Hansen and others as a useful metric to help guide policymaking. RCPs, SSPs, and other similar scenarios have also been used by researchers to simulate the rate of forced climate changes. By definition, ECS presumes that ongoing emissions will offset the ocean and land carbon sinks following the step-wise perturbation in atmospheric CO₂.

ECS response time is proportional to ECS and is principally regulated by the thermal inertia of the uppermost mixed layer and adjacent lower ocean layers. Main time constants fitted to the results from climate models have ranged from a few decades when ECS is low, to as long as a century when ECS is high. A portion of the variation between estimates arises from different treatments of heat transport into the deep ocean.

Components

Thermal inertia

The observed accumulation of energy in the oceanic, land, ice, and atmospheric components of Earth's climate system since 1960. The rate of rise has been partially slowed by the system's thermal inertia.

Thermal inertia is a term which refers to the observed delays in a body's temperature response during heat transfers. A body with large thermal inertia can store a big amount of energy because of its heat capacity, and can effectively transmit energy according to its heat transfer coefficient. The consequences of thermal inertia are inherently expressed via many climate change feedbacks because of their temperature dependencies; including through the strong stabilizing feedback of the Planck response.

Ocean inertia

The global ocean is Earth's largest thermal reservoir that functions to regulate the planet's climate; acting as both a sink and a source of energy. The ocean's thermal inertia delays some global warming for decades or centuries. It is accounted for in global climate models, and has been confirmed via measurements of ocean heat content. The observed transient climate sensitivity is proportional to the thermal inertia time scale of the shallower ocean.

Ice sheet inertia

Even after CO₂ emissions are lowered, the melting of ice sheets will persist and further increase sea-level rise for centuries. The slower transportation of heat into the extreme deep ocean, subsurface land sediments, and thick ice sheets will continue until the new Earth system equilibrium has been reached.

Permafrost also takes longer to respond to a warming planet because of thermal inertia, due to ice rich materials and permafrost thickness.

Inertia from carbon cycle feedbacks

See also: Climate change feedback § Carbon cycle

The impulse response following a 100 GtC injection of CO₂ into Earth's atmosphere. The relative inertial effect of positive vs. negative feedback during early years is indicated by the pulse fraction which ultimately remains.

Earth's carbon cycle feedback includes a destabilizing positive feedback (identified as the climate-carbon feedback) which prolongs warming for centuries, and a stabilizing negative feedback (identified as the concentration-carbon feedback) which limits the ultimate warming response to fossil carbon emissions. The near-term effect following emissions is asymmetric with latter mechanism being about four times larger, and results in a significant net slowing contribution to the inertia of the climate system during the first few decades following emissions.

Ecological inertia

Main articles: Ecological stability and Ecological resilience

Depending on the ecosystem, effects of climate change could show quickly, while others take more time to respond. For instance, coral bleaching can occur in a single warm season, while trees may be able to persist for decades under a changing climate, but be unable to regenerate. Changes in the frequency of extreme weather events could disrupt ecosystems as a consequence, depending on individual response times of species.

Policy implications of inertia

The IPCC concluded that the inertia and uncertainty of the climate system, ecosystems, and socioeconomic systems implies that margins for safety should be considered. Thus, setting strategies, targets, and time tables for avoiding dangerous interference through climate change. Further the IPCC concluded in their 2001 report that the stabilization of atmospheric CO₂ concentration, temperature, or sea level is affected by:

• The inertia of the climate system, which will cause climate change to continue for a period after mitigation actions are implemented.
• Uncertainty regarding the location of possible thresholds of irreversible change and the behavior of the system in their vicinity.
• The time lags between adoption of mitigation goals and their achievement.

Fossil fuel subsidies

From Wikipedia, the free encyclopedia

Fossil fuel subsidies per capita

Fossil fuel subsidies as share of GDP

Fossil fuel subsidies are energy subsidies on fossil fuels. Under a narrow definition, fossil fuel subsidies totalled around $1.5 trillion in 2022. Under more expansive definition, they totalled around $7 trillion. They may be tax breaks on consumption, such as a lower sales tax on natural gas for residential heating; or subsidies on production, such as tax breaks on exploration for oil. Or they may be free or cheap negative externalities; such as air pollution or climate change due to burning gasoline, diesel and jet fuel. Some fossil fuel subsidies are via electricity generation, such as subsidies for coal-fired power stations.

Eliminating fossil fuel subsidies would reduce the health risks of air pollution, and would greatly reduce global carbon emissions thus helping to limit climate change. As of 2021, policy researchers estimate that substantially more money is spent on fossil fuel subsidies than on environmentally harmful agricultural subsidies or environmentally harmful water subsidies. The International Energy Agency says: "High fossil fuel prices hit the poor hardest, but subsidies are rarely well-targeted to protect vulnerable groups and tend to benefit better-off segments of the population."

Despite the G20 countries having pledged to phase-out inefficient fossil fuel subsidies, as of 2023 they continue because of voter demand, or for energy security.

Definition

Fossil fuel subsidies have been described as "any government action that lowers the cost of fossil fuel energy production, raises the price received by energy producers, or lowers the price paid by energy consumers." Including negative externalities such as health costs results in a much larger total. Thus by the IMF definition they are far larger than by the OECD and International Energy Agency (IEA) definitions.

Subsidies for electricity and heat may be taken into account, depending on the share produced by fossil fuels. Sometimes there are disputes about what definition to use: for example the UK government said in 2021 that it uses the IEA definition and does not subsidize fossil fuels, but others said the same year that under the OECD definition it does.

Measurement

Subsidies may be estimated by adding up direct subsidies from government, comparing prices in a country to world market prices, and sometimes attempting to include the cost of damage to human health and the climate. Setting fossil fuel prices that reflect their true cost would cut global CO₂ emissions by 10% by 2030, according to the IPCC in 2023. The International Institute for Sustainable Development say that G7 countries should reveal their subsidies every year under Sustainable Development Goal (SDG) indicator 12.c.1 (fossil fuel subsidies).

The fiscal cost of government support for fossil fuels was 1.1 trillion USD in 2023. Most (90%) of which is related to the consumption of fossil fuels. The fiscal cost of support for residential users was 189 billion USD in 2023, while for manufacturing and other industries it was 103.8 billion USD. The OECD said that "Most of this support lacked systematic targeting towards those in greatest need, raising both equity and efficiency concerns." Economic incentives to decarbonise from fuel taxes, carbon taxes, emissions trading systems (ETSs) and price-reducing support mechanisms - summarised in the net Effective Carbon Rate (Net ECR) - averaged EUR 14.0/tCO2e in 2023. The share of GHG emissions covered by a positive Net ECR was 42%; 27% of GHG emissions are covered by explicit carbon prices (carbon taxes or ETSs).

The OECD said that "The high fiscal cost of government support for fossil fuels and low Net ECR highlight the challenges of staying on track with net zero commitments in the face of economic and geopolitical pressures. Reforms should focus on better targeting those most in need and phasing out inefficient support for fossil fuels as soon as possible to enable the release of much-needed resources for the net zero transition and help accelerate innovation for energy efficiency. Given the high costs of inaction, governments should reaffirm and implement their SDG commitment to phase out and reform inefficient support to fossil fuels to align fiscal policy with climate goals."

Effects

Subsidies on consumption reduce the price of energy for end consumers, for example the cost of gasoline for car drivers in Iran. This may win votes at elections and some people in government say it helps poorer citizens.

The consensus among economists is that the rich get most absolute benefit from fossil fuel subsidies, for example the poorest people do not usually own cars. But removing the subsidies may hit poor people via indirect price increases such as food prices, so they get a lot of benefit relative to their total income. Producers, such as oil companies, say that increasing taxes on them would cause unemployment and reduce national energy security.

Health effects

Subsidies are estimated to cause hundreds of thousands of deaths from air pollution each year.

Economic effects

See also: Subsidy § Economic effects

Fossil fuel subsidies are a negative carbon price and use government money that could be spent on other things. The International Monetary Fund says that by encouraging excess energy use they can make countries more vulnerable to variation in international energy prices. However some governments say that the subsidies are necessary to shield citizens from such variation. According to the International Energy Agency (IEA) phasing out fossil fuel subsidies would benefit energy markets, climate change mitigation and government budgets.

Environmental effects

See also: Environmental impact of the petroleum industry, Health and environmental impact of the coal industry, Environmental impact of electricity generation § Fossil fuels, Externality, and Subsidy § Environmental externalities

Subsidies affect the environment and removing them would save the carbon budget and help limit climate change.

Phase-out

See also: Fossil fuel phase-out § Phase-out of fossil fuel subsidies

Many economists recommend replacing consumption subsidies with direct payments targeted at poor people or households. The best way to use the money saved will likely require country specific studies. However phase-out is politically difficult.

History

Tax breaks for oil and gas exploration have been in place since at least the early 20th century.

Subsidies by fuel

In 2023, the OECD estimated that coal subsidies amounted to 27.7 billion USD, oil to 400 billion USD, and gas to 343 billion USD.

Subsidies by country

See also: Gasoline and diesel usage and pricing § Countries with subsidised gasoline

The International Energy Agency estimates that governments subsidised consumption of fossil fuels by US $1 trillion in 2022. At their meeting in September 2009 the G-20 countries committed to "rationalize and phase out over the medium term inefficient fossil fuel subsidies that encourage wasteful consumption". Many say that all fossil fuel subsidies are inefficient.

The 2010s saw many other countries reducing energy subsidies, for instance in July 2014 Ghana abolished all diesel and gasoline subsidies, whilst in the same month Egypt raised diesel prices 63% as part of a raft of reforms intended to remove subsidies within 5 years.

In Sept, 2021, the IMF produced a working paper with estimates for the subsidies caused by the gap between the efficient price of fossil fuels and user prices. "Underpricing for local air pollution costs is the largest contributor to global fossil fuel subsidies, accounting for 42 percent, followed by global warming costs (29 percent), other local externalities such as congestion and road accidents (15 percent), explicit subsidies (8 percent) and foregone consumption tax revenue (6 percent)." Globally, fossil fuel subsidies were $5.9 trillion which amounts to 6.8% of GDP in 2020 and are expected to rise to 7.4% in 2025.

The table below shows excerpts from a 2021 IMF study for 20 countries with biggest subsidies. It also shows the biggest component of explicit subsidies, electricity costs, and of implicit subsidies, coal. See these references for complete data: (Units are billions of 2021 US dollars.)

Fossil fuel subsidies - top 20 countries US$ billions

2020	Explicit Subsidies		Implicit Subsidies		Total
	Electricity	Total	Coal	Total
China	13.69	15.73	1,391.78	2,187.50	2,203.23
United States	0.00	16.06	121.45	646.00	662.05
Russia	25.14	77.36	195.26	445.26	522.62
India	8.71	16.18	162.72	230.89	247.07
Japan	2.74	4.75	57.69	164.80	169.55
Saudi Arabia	8.72	53.75	0.00	104.36	158.11
Iran	26.51	41.72	4.59	111.05	152.77
Indonesia	5.49	11.96	32.85	115.13	127.09
Turkey	0.24	4.11	52.59	112.61	116.72
Egypt	7.32	9.69	1.89	95.38	105.07
Germany	0.00	3.43	25.50	68.32	71.75
Korea, South	0.00	0.58	28.93	68.39	68.98
Canada	2.43	10.34	3.04	53.69	64.03
South Africa	5.62	5.72	30.41	44.84	50.56
Kazakhstan	4.57	9.93	19.11	37.05	46.98
Taiwan	1.67	2.58	25.42	43.55	46.13
Australia	2.14	5.57	14.85	38.92	44.49
Ukraine	4.57	7.76	28.76	35.87	43.63
Malaysia	0.90	3.52	5.52	39.50	43.02
Brazil	0.00	5.80	4.60	37.17	42.97
World total	189.53	454.79	2,362.26	5,402.57	5,857.36

Canada

The Canadian federal government offers subsidies for fossil fuel exploration and production and Export Development Canada regularly provides financing to oil and gas companies. A 2018 report from the Overseas Development Institute, a UK-based think tank, found that Canada spent a greater proportion of its GDP on fiscal support to oil and gas production in 2015 and 2016 than any other G7 country.

In 2018, in response to low Canadian oil prices, the federal government announced $1.6 billion in financial support for the oil and gas sector: $1 billion in loans to oil and gas exporters from Export Development Canada, $500 million in financing for "higher risk" oil and gas companies from the Business Development Bank of Canada, $50 million through Natural Resources Canada's Clean Growth Program, and $100 million through Innovation, Science and Economic Development Canada's Strategic Innovation Fund. Minister of Natural Resources Amarjeet Sohi said that this financing is "not a subsidy for fossil fuels", adding that "These are commercial loans, made available on commercial terms. We have committed to phasing out inefficient fossil fuel subsidies by 2025, and we stand by that commitment". Canada has committed to phase out fossil fuel subsidies by 2023.

Canadian provincial governments also offer subsidies for the consumption of fossil fuels. For example, Saskatchewan offers a fuel tax exemption for farmers and a sales tax exemption for natural gas used for heating.

A 2018 report from the Overseas Development Institute was critical of Canada's reporting and transparency practices around its fossil fuel subsidies. Canada does not publish specific reports on its fiscal support for fossil fuels, and when Canada's Office of the Auditor-General attempted an audit of Canadian fossil fuel subsidies in 2017, they found much of the data they needed was not provided by Finance Canada. Export Development Canada reports on their transactions related to fossil fuel projects, but do not provide data on exact amounts or the stage of project development.

China

The energy policy of China says that energy security requires subsidy of production and consumption of fossil fuels including coal, oil and natural gas.

India

In financial year 2021 fossil fuel subsidies have been estimated at 9 times renewable energy subsidies: with INR 55,250 crore for oil and gas and INR 12,976 crore for coal.

Iran

See also: Economy of Iran, Energy in Iran, and 2007 Gasoline Rationing Plan in Iran § Fuel smuggling

Contrary to the subsidy reform plan's objectives, under President Rouhani the volume of Iranian subsidies given to its citizens on fossil fuel increased 42% in 2019 to over 15% of Iran's GDP and 16% of total global energy subsidies. This has made Iran the world's largest subsidizer of energy prices. This situation is leading to highly wasteful consumption patterns, large budget deficits, price distortions in its entire economy, pollution and very lucrative (multi-billion dollars) contraband (because of price differentials) with neighbouring countries each year by rogue elements within the Iranian government supporting the status-quo.

Libya

Libya had the highest subsidy by percent GDP in 2020 at 17.5%.

Russia

See also: Energy policy of Russia

Russia holds the world's largest natural gas reserves (27% of total), the second-largest coal reserves, and the eighth-largest oil reserves. Russia is the world's third-largest energy subsidizer as of 2015. The country subsidizes electricity and natural gas as well as oil extraction. Approximately 60% of the subsidies go to natural gas, with the remainder spent on electricity (including under-pricing of gas delivered to power stations). For oil extraction the government gives tax exemptions and duty reductions amounting to about 22 billion dollars a year. Some of the tax exemptions and duty reductions also apply to natural gas extraction, though the majority is allocated for oil. The large subsidies of Russia are costly and it is recommended in order to help the economy that Russia lowers its domestic subsidies. However, the potential elimination of energy subsidies in Russia carries the risk of social unrest that makes Russian authorities reluctant to remove them.

Saudi Arabia

Most energy subsidies in Saudi Arabia are implicit in nature. This is due to the fact domestic oil prices are generally below global market prices but above domestic production costs, leading to forgone revenue but not direct subsidy costs. Contrary to the estimates above, a recent paper posits that the incremental electricity subsidy in Saudi Arabia has been eliminated as a result of the 2018 domestic energy price reforms.

Turkey

In the 21st century, Turkey's fossil fuel subsidies are around 0.2% of GDP, including at least US$14 billion (US$169 per person) between January 2020 and September 2021. If unpaid damages (such as health damage from air pollution) are included road fuel subsidy is estimated at over 400 dollars per person per year and for all fossil fuels over one thousand dollars. Data on finance for fossil fuels by state-owned banks and export credit agencies is not public. The energy minister Fatih Dönmez supports coal and most energy subsidies are for coal, which the OECD has strongly criticised. Capacity mechanism payments to coal-fired power stations in Turkey in 2019 totalled ₺720 million (US$130 million) compared to ₺542 million (US$96 million) to gas-fired power stations in Turkey. In 2022 these payments totalled over US$200 million. As of 2020, the tax per unit energy on gasoline was higher than diesel, despite diesel cars on average emitting more lung damaging NOx (nitrogen oxide).

Venezuela

2020 subsidy has been estimated at 7% of GDP. In 2021 the subsidized and rationed gasoline price was around 25 US cents a litre, half of the unsubsidized price.

Brain in a vat

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Brain_in_a_vat

A brain in a vat that believes it is walking

In philosophy, the brain in a vat (BIV) is a scenario used in a variety of thought experiments intended to draw out certain features of human conceptions of knowledge, reality, truth, mind, consciousness, and meaning. Gilbert Harman conceived the scenario, which Hilary Putnam turned into a modernized version of René Descartes's evil demon thought experiment. Following many science fiction stories, the scenario involves a mad scientist who might remove a person's brain from the body, suspend it in a vat of life-sustaining liquid, and connect its neurons by wires to a supercomputer that would provide it with electrical impulses identical to those a brain normally receives. According to such stories, the computer would then be simulating reality (including appropriate responses to the brain's own output) and the "disembodied" brain would continue to have perfectly normal conscious experiences, like those of a person with an embodied brain, without these being related to objects or events in the real world. According to Putnam, the thought of "being a brain-in-a-vat" is either false or meaningless.

Considered a cornerstone of semantic externalism, the argument produced significant literature. The Matrix franchise and other fictional works (below) are considered inspired by Putnam's argument.

Intuitive version

Putnam's argument is based on the causal theory of reference, where a word describing a spatio-temporal object is meaningful if and only if it possesses an information-carrying causal relation to whatever it denotes. Next, an "envatted" brain is one whose entire world is composed of (say) electric manipulations performed by a computer simulation to which it is connected. With this much in place, consider the sentence "I am a brain in a vat" (BIV). In case you are not a brain in a vat, the sentence is false by definition. In case you are a brain in a vat, the terms "brain" and "vat" fail to denote actual brains and actual vats with whom you had an information-carrying causal interaction since, again by definition, the only interaction available is with the computer simulation, which is not information carrying. By the causal theory of reference, such references do not carry referential meaning. Thus, the sentence "I am a brain in a vat" is either false or meaningless.

Uses

The simplest use of brain-in-a-vat scenarios is as an argument for philosophical skepticism and solipsism. A simple version of this runs as follows: since the brain in a vat gives and receives exactly the same impulses as it would if it were in a skull, and since these are its only way of interacting with its environment, then it is not possible to tell, from the perspective of that brain, whether it is in a skull or a vat. Yet in the first case, most of the person's beliefs may be true (if they believe, say, that they are walking down the street, or eating ice-cream); in the latter case, their beliefs are false. Since the argument says if one cannot know whether one is a brain in a vat, then one cannot know whether most of one's beliefs might be completely false. Since, in principle, it is impossible to rule out oneself being a brain in a vat, there cannot be good grounds for believing any of the things one believes; a skeptical argument would contend that one certainly cannot know them, raising issues with the definition of knowledge. Other philosophers have drawn upon sensation and its relationship to meaning in order to question whether brains in vats are really deceived at all, thus raising wider questions concerning perception, metaphysics, and the philosophy of language.

The brain-in-a-vat is a contemporary version of the argument given in Hindu Maya illusion, Zhuangzi's "Zhuangzi dreamed he was a butterfly", and the evil demon in René Descartes' Meditations on First Philosophy.

Recently, many contemporary philosophers believe that virtual reality will seriously affect human autonomy as a form of brain in a vat. But another view is that VR will not destroy our cognitive structure or take away our connection with reality. On the contrary, VR will allow us to have more new propositions, new insights and new perspectives to see the world.

Philosophical debates

While the disembodied brain (the brain in a vat) can be seen as a helpful thought experiment, there are several philosophical debates surrounding the plausibility of the thought experiment. If these debates conclude that the thought experiment is implausible, a possible consequence would be that we are no closer to knowledge, truth, consciousness, representation, etc. than we were prior to the experiment.

Argument from biology

A human brain in jar

One argument against the BIV thought experiment derives from the idea that the BIV is not – and cannot be – biologically similar to that of an embodied brain (that is, a brain found in a person). Since the BIV is disembodied, it follows that it does not have similar biology to that of an embodied brain. That is, the BIV lacks the connections from the body to the brain, which renders the BIV neither neuroanatomically nor neurophysiologically similar to that of an embodied brain. If this is the case, we cannot say that it is even possible for the BIV to have similar experiences to the embodied brain, since the brains are not equal. However, it could be counter-argued that the hypothetical machine could be made to also replicate those types of inputs.

Argument from externalism

A second argument deals directly with the stimuli coming into the brain. This is often referred to as the account from externalism or ultra-externalism. In the BIV, the brain receives stimuli from a machine. In an embodied brain, however, the brain receives the stimuli from the sensors found in the body (via touching, tasting, smelling, etc.) which receive their input from the external environment. This argument oftentimes leads to the conclusion that there is a difference between what the BIV is representing and what the embodied brain is representing. This debate has been hashed out, but remains unresolved, by several philosophers including Uriah Kriegel, Colin McGinn, and Robert D. Rupert, and has ramifications for philosophy of mind discussions on (but not limited to) representation, consciousness, content, cognition, and embodied cognition.

Argument from incoherence

A third argument against BIV comes from a direction of incoherence, which was presented by the philosopher Hilary Putnam. He attempts to demonstrate this through the usage of a transcendental argument, in which he tries to illustrate that the thought experiment's incoherence lies on the basis that it is self-refuting. This relationship is further defined, through a theory of reference that suggested reference can not be assumed, and words are not automatically intrinsically connected with what it represents. This theory of reference would later become known as semantic externalism. This concept is further illustrated when Putnam establishes a scenario in which a monkey types out Hamlet by chance; however, this does not mean that the monkey is referring to the play, because the monkey has no knowledge of Hamlet and therefore can not refer back to it. He then offers the "Twin Earth" example to demonstrate that two identical individuals, one on the Earth and another on a "twin Earth", may possess the exact same mental state and thoughts, yet refer to two different things. For instance, when people think of cats, the referent of their thoughts would be the cats that are found on Earth. However, people's twins on twin Earth, though possessing the same thoughts, would instead be referring not to Earth's cats, but to twin Earth's cats. Bearing this in mind, he writes that a "pure" brain in a vat, i.e., one that has never existed outside of the simulation, could not even truthfully say that it was a brain in a vat. This is because the BIV, when it says "brain" and "vat", can only refer to objects within the simulation, not to things outside the simulation it does not have a relationship with. Putnam refers to this relationship as a "causal connection" which is sometimes referred to as "a causal constraint". Therefore, what it says is demonstrably false. Alternatively, if the speaker is not actually a BIV, then the statement is also false. He concludes, then, that the statement "I'm a BIV" is necessarily false and self-refuting. This argument has been explored at length in philosophical literature since its publication. A potential loophole in Putnam's reference theory is that a brain on Earth that is "kidnapped", placed into a vat, and subjected to a simulation could still refer to brains and vats which are real in the sense of Putnam, and thus correctly say it is a brain in a vat according to Putnamian reference theory. However, the notion that the "pure" BIV is incorrect and the reference theory underpinning it remains influential in the philosophy of mind, language and metaphysics. Anthony L. Brueckner has formulated an extension of Putnam's argument which rules out this loophole by employing a disquotational principle. It will be discussed in the following two sections.

Reconstructions of Putnam's argument

An issue that has arisen with Putnam's argument is that his premises only imply the metalinguistic statement "my utterances of 'I am a BIV' are false", but a skeptic may demand the object-language statement "I am a BIV" to be proven. To combat this issue, various philosophers have reconstructed Putnam's argument. Some, like Anthony L. Brueckner and Crispin Wright, have taken approaches that utilize disquotational principles. Others, like Ted A. Warfield, have taken approaches that focus on the concepts of self-knowledge and priori.

The disjunctive argument

One of the earliest but influential reconstructions of Putnam's transcendental argument was suggested by Anthony L. Brueckner. Brueckner's reconstruction is as follows: "(1) Either I am a BIV (speaking vat-English) or I am a non-BIV (speaking English). (2) If I am a BIV (speaking vat-English), then my utterances of 'I am a BIV' are true if I have sense impressions as of being a BIV. (3) If I am a BIV (speaking vat-English), then I do not have sense impressions as of being a BIV. (4) If I am a BIV (speaking vat-English), then my utterances of 'I am a BIV' are false. [(2), (3)] (5) If I am a non-BIV (speaking English), then my utterances of 'I am a BIV' are true if I am a BIV. (6) If I am a non-BIV (speaking English), then my utterances of 'I am a BIV' are false. [(5)] (7) My utterances of 'I am a BIV' are false. [(1), (4), (6)]" Though these premises further define Putnam's argument, they do not so far prove "I am not a BIV", because, although the premises imply the metalinguistic statement "my utterances 'I am a BIV' are false", they do not yet imply the object-language statement "I am not a BIV". To achieve the Putnamian conclusion, Brueckner strengthens his argument by employing the disquotational principle "My utterances of 'I am not a BIV' are true if I am not a BIV." This statement is justified since the metalanguage that contains the tokens for the disquotational principle also contains the object language tokens to which the utterances 'I am not a BIV' belong.