Science in Society Archive

Fracking for Shale Gas

Shale gas could be a useful stop-gap substitute for more conventional fossil fuels on our way towards fully green renewable energies, but health and environmental risks including pollution to ground water remain to be addressed Prof Peter Saunders

Shale gas

Shale gas is being hailed as the new source of energy that will keep the world’s economy going as oil supplies start to dwindle. It will, so we are told, make developed countries less dependent on the politically unstable Middle East and it will contribute to mitigating climate change because it produces less greenhouse gas than coal or oil.

The International Energy Agency (IEA) estimates that by 2035, as much as 40% of the world’s gas might be ‘unconventional’, of which by far the greatest part will be shale gas [1]. (The other chief forms of unconventional gas (UCG) are coal bed methane, which, as its name suggests, is found in coal seams, and ‘tight gas’, which is found in hard rock such as limestone or sandstone.)  

The US is already producing about 10% of its natural gas (i.e. about 2.5% of its total energy consumption) from shale deposits, and the US Energy Information Administration estimates that by 2035 this will rise to 46% [2].  Other countries, such as the UK, are also planning to exploit their shale gas deposits, though few of them apart from China have anything like the same amounts available. The current estimate is that there may be about 200 trillion cubic metres (Tcm) of technically recoverable (as opposed to economically recoverable) shale gas reserves in the world, about 45  Tcm of tight gas and 25 Tcm of coal bed methane. This can be compared with the 425 Tcm of technically recoverable conventional natural gas, of which about 190 Tcm are considered easily recoverable [3].


Conventional natural gas (hydrocarbon gas, mainly methane) comes from permeable reservoir rocks where it is trapped by a layer of impermeable rock above it. It can be extracted simply by drilling through that layer and into the reservoir. Shale is not very permeable and needs no impermeable layer to prevent the gas it contains from escaping. By the same token, however, little of that gas will be released if one simply drills a well into the shale.  One must fracture the shale to provide channels through which the gas can escape. Then water under high pressure is used to force the gas out into the well. Taken together, the two techniques are referred to as hydraulic fracturing, or fracking (see diagram).

Even with fracking, only gas relatively close to the well can be recovered, so extracting shale gas was not economic until engineers developed ways of doing accurate horizontal drilling. This very much cuts the cost by reducing the number of wells that have to be drilled, as each can be extended some distance from the vertical bore. Engineers have also found combinations of chemicals and other materials such as sand that help them to open cracks in the rock and keep them open, and also to force the gas out.

The pros and cons

At first glance, shale gas appears an attractive prospect, certainly when compared with alternatives such as tar sands or the Arctic Ocean. There are at least two major problems, however. In the first place, while natural gas contributes less to climate change than do other fossil fuels, it still contributes. If shale gas is used to replace coal and oil, it will indeed reduce greenhouse gas emissions (provided the shale gas is as clean as conventional natural gas, which is not often the case, and minimum leakage occurs [4]). If, on the other hand, countries simply add shale gas to their existing fossil fuel consumption, then emissions will continue to rise.

Having shale gas available will also tempt governments not to develop renewable energy sources. It will be all too tempting for legislators to put off the day when action will be needed, preferably until it becomes a problem for their successors.

If countries like the US use more shale gas and import less oil, the price of oil will fall. This might simply be through the law of supply and demand, but it might also happen because the OPEC countries would agree to increase production to maintain their incomes. Other countries would be able to buy more oil for the same money and so increase their consumption of fossil fuels. Thus even if the US and other countries with large deposits of shale gas were to reduce their greenhouse gas emissions, the net global effect could still be an increase.

The extraction of natural gas by fracking also has a direct impact on the environment, both globally and locally. In the first place, there can be sizeable amounts of methane released into the atmosphere (remember that methane is a much more potent greenhouse gas than CO2).  Fracking can lead to the pollution of both rivers and aquifers. It requires large amounts of water and so can deprive other users of their supply. This is exacerbating an already dwindling global potable water supply (see [5] World Water Supply in Jeopardy, SiS 55). The large number of wells that are typically required can very much affect the environment of people who live in the area. Fracking can cause earthquakes: so far these have all been small but we cannot assume all future earthquakes will be.

Because the US was the first into fracking, the problems have emerged there first. Companies are drilling wherever they can, and those who live on the land over the shale can find it very difficult to stop them. Big cities like Tulsa and Dallas have been able to ban fracking within the city limits but smaller municipalities, such as Gardendale in Texas and Longmont in Colorado, are having less success [6].  In Wyoming, Texas, Pennsylvania and New York, local people claim that their groundwater has been contaminated with methane and other hydrocarbons [7]. The companies maintain that there is no proof they are responsible, and it is very difficult to contradict them in the courts because of a lack of baseline data, i.e. measurements made before fracking began.

Wastewater is an especially serious problem. A well can produce over a million gallons of wastewater containing both the chemicals and other materials that were added to make the process more efficient, and also substances such as benzene and radon that were safely buried deep in the ground and are now being brought to the surface.

A common practice, for example in Pennsylvania [8, 9], has been to transport the wastewater to sewage plants where it is treated and then released into rivers from which drinking water is later taken. The problem is that ordinary sewage plants cannot remove all the contaminants, especially radioactive substances such as radon. (Radon is a colourless, odourless, tasteless gas that is found in very small concentrations almost everywhere and in larger concentrations in shale and granite. It is a well-known hazard in some mines and in areas such as Aberdeenshire in Scotland that are built on granite. The US Environmental Protection Authority (EPA) estimates there are 21 000 radon-induced lung cancer deaths per year in the US [10].) Processing wastewater is made even less effective by the fact that drilling companies are not obliged to reveal what they put into the water in the first place; they can hide behind the protection of commercial confidentiality.

As for the UK, while it is known that there are considerable amounts of shale gas, perhaps as much as 5.5 Tcm, estimates of how much of this is economically recoverable vary widely. The UK is also a very densely populated country, and this limits the area in which fracking is likely to be permitted. The only company currently involved, Cuadrilla, argues that the shale layer it has been concentrating on - in Lancashire - is thicker than those found in the US and that fewer wells would therefore be required, but this remains to be seen [11].

In the meantime, the Royal Society and the Royal Academy of Engineering (RS/RAE) have published a report in which they consider only the health and environmental risks associated with fracking [12]. They explicitly did not deal with the subsequent use of shale gas, in particular the climate risks.

Within their remit, the RS/RAE report is a useful contribution. They recommend monitoring groundwater, seismicity, well integrity, and leakages of methane and other gases into the atmosphere. The monitoring should commence before any extraction begins and it should continue after the well is abandoned. Water use should be minimised, waste water should be recycled as far as possible, and arrangements for dealing with waste water should be planned from the outset. An Environmental Risk Assessment should be mandatory and while a number of regulatory agencies are likely to be involved, a single body should take the lead.

European Parliament speaks out

The European Commission is currently considering what its policy on shale gas should be. A meeting of the European Parliament took place on 21 November 2012, and a number of important points were noted [13].

First, many governments in Europe including France, Bulgaria, North Rhine Westphalia in Germany, Fribourg and Vaud in Switzerland, as well as a number of US states (North Carolina, New York, New Jersey and Vermont and more than 100 local governments)  and other countries around the world (South Africa, Quebec in Canada, New South Wales in Australia) currently have a ban or moratorium in place on the use of hydraulic fracturing for the extraction of oil and gas from shale or other  ‘tight’ rock formations; while a number of Member States, such as the Czech Republic, Romania and Germany are currently considering a moratorium. Second, it drew attention to the fact that shale gas exploration projects are not generally subject to an environmental impact assessment despite the environmental risks of such projects. Third, the Environmental Liability Directive does not oblige operators to take out adequate insurance. Fourth, there are insufficient data on fracturing chemicals and environmental and health risks associated with hydraulic fracturing. Fifth, it is essential that the precautionary and the polluter-pays principles are applied to any future decisions about the development of fossil fuel resources in Europe. Sixth, any decisions on exploitation of unconventional fossil fuels (UFF) should be seen in the context of the need to cut emissions.

The European Parliament also highlighted the international situation. Increased shale gas exploration and production worldwide will lead to a considerable increase in fugitive methane emissions, and the overall greenhouse warming potential of shale gas has not been evaluated. The exploitation of unconventional oil and gas resources could therefore hamper the achievement of UN Millennium Development Goal (MDG) 7 – ensuring environmental sustainability. The impact poses a particular threat in poor countries, where local communities largely depend on natural resources for agriculture and fisheries.

The very large volumes of water required for shale gas extraction may make it difficult to achieve the MDG 7 targets concerning access to clean water and food security, especially in poor countries that already face a severe scarcity of water.

Land acquisitions for oil and gas mining are a major driver of land-grabbing in developing countries and this can pose a significant threat to the world’s indigenous communities, farmers and poor people in terms of access to water, fertile soil and food. All European economic entities should always act in a transparent manner and in close consultation with all appropriate government bodies and local communities on issues of land leases and/or acquisitions.

In addition to regulations in the countries where they operate, international oil companies are also subject to the jurisdiction of the courts in the countries on whose stock exchange they are listed. Home country regulation should therefore provide an effective means of protecting human rights in situations where accountability gaps exist, on the model of the United States Alien Tort Claims Acts. Voluntary guidelines such as the Global Reporting Initiative, the UN Global Compact and the OECD Guidelines for Multinational Enterprises already exist but are insufficient to mitigate the negative impact of extraction. The current revision of the EU Accounting and Transparency Directives provides an opportunity to prevent tax evasion and corruption by extractive industries. The European Commission should identify new options for strengthening standards on the responsibilities of transnational corporations with regard to social and environmental rights. Some unconventional oil and gas companies operate to different standards worldwide. Member States should require companies whose headquarters are in the EU to apply EU standards in all their operations worldwide.

The European Parliament’s many recommendations include:

1. The risks of UFF extraction should be contained through pre-emptive measures including proper planning, testing, use of new and best available technologies, best industry practices and continuous data collection, monitoring and reporting conducted within a robust regulatory framework. It is crucial, before the start of UFF operations, to require measuring baseline levels of naturally occurring methane and chemicals in groundwater in aquifers and current air quality levels at potential drilling sites.

2. Because the sustainability of shale gas is not yet proven, the Commission and Member States should assess thoroughly greenhouse gas emissions during the entire process of extraction and production.

3. In the context of liability, the burden of proof for shale gas operators should be reversed where the balance of probability indicates that shale gas operations were the cause of the environmental damage.

4. The Commission should bring forward proposals to explicitly include fracking fluids as ‘hazardous waste’ under Annex III of the European Waste Directive (2008/98/EC).

5. Because of the relatively high water volumes involved in hydraulic fracturing and given that water is a particularly sensitive resource in the EU, there should be advance water provision plans based on local hydrology and with consideration for local water resources, the needs of other local water users and capacities for wastewater treatment.

6. The Commission should ensure that European environmental standards are met in full and that breaches are appropriately penalised.

7. The industry should take the measures needed to prevent the status of relevant bodies of groundwater from deteriorating and thereby maintain good groundwater status as defined in the Water Framework Directive and the Groundwater Directive.

8. There should be a blanket ban on hydrofracking in certain sensitive and particularly endangered areas, such as in and beneath drinking water protection areas and in coal mining areas.

9. Effective prevention requires consistent monitoring of strict adherence to the highest standards and practices in well-bore construction and maintenance.

10. On-site closed-loop water recycling using steel storage tanks offers the most environmentally sound way of treating flow-back water. The injection of flow-back waste waters for disposal into geological formations should be rejected.

11. There should be a mandatory obligation for all operators to fully disclose the chemical composition and concentration of fracturing fluids and to fully comply with existing EU legislation under the REACH regulation.

12. Mutual non-disclosure agreements regarding damage to environmental, human and animal health, such as those which have been in force between landowners in the vicinity of shale gas wells and shale gas operators in the US, would not be in line with EU and Member State obligations under the Aarhus Convention, the Access to Information Directive (2003/04/EC) and the Environmental Liability Directive.

The European Parliament has gone much further than the RS/RAE report. Unfortunately, it has very little power to put into place its recommendations. About all it can do is to forward its resolution to the Council and the Commission and the parliaments of the member states and hope that they will be influenced by it.

Shale gas could be a useful stop-gap in the transition towards fully renewables energies (see [14] Green Energies - 100% Renewable by 2050, I-SIS publication) if it is used instead of, rather than in addition to, other fossil fuels, and if it is extracted in ways that are not detrimental to health and the environment, and does not contribute excessively to climate change. The European Parliament knows what has to be done. The problem is to convince the European Commission and our own governments to do it.

Article first published 20/02/13


  1. International Energy Agency (2012). World Energy Outlook 2012.
    (Executive Summary available at )
  2. US Energy Information Administration (2012). What is shale gas and why is it important?  3/1/13.
  3. Pearson I, Zeniewski P, Gracceva F, Zastera P, McGlade C, Sorrell S, Speirs J, and Thonhauser G (2012). Unconventional Gas: Potential Energy Market Impacts in the European Union. European Union, Luxembourg.
  4.  “Shale gas: how clean is it?”, Andrew Nikiforuk, 11 January 2013, Resilience,
  5. Ho MW (2012). World Water Supply in Jeopardy. Science in Society 56, 38-43.
  6.  “When fracking came to suburban Texas”, Suzanne Goldenberg. The Guardian, 31 December 2012.
  7.  “Is fracking behind contamination in Wyoming groundwater?” Jeff Tollefson, Nature News, 9 October 2012.
  8.  “Regulation Lax as Gas Wells’ Tainted Water Hits Rivers.” Ian Urbina, New York Times, 26 February, 2011.
  9. “Documents: Natural Gas’s Toxic Waste.” New York Times, 26 February, 2011.
  10. US Environmental Protection Agency (2012). A citizen’s guide to radon.
  11. “Energy secretary allows fracking operations to resume”, The Telegraph, 13 December 2012.
  12. Royal Society/Royal Academy of Engineering (2012). Shale Gas Extraction in the UK: a review of hydraulic fracturing.
  13. European Parliament (2012). Resolution of 21 November 2012 on the environmental impacts of shale gas and shale oil extraction activities (2011/2308(INI)).
  14. Ho MW, Cherry B, Burcher S and Saunders PT. Green Energies, 100% Renewables by 2050, ISIS/TWN, 2009,

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There are 5 comments on this article so far. Add your comment above.

Morag Parnell Comment left 21st February 2013 04:04:17
Good to see this from ISIS. There are very lively campaigns opposing these developments across the world including in the UK - see frack-off Concern for not only climate change but also the use of toxic chemicals in drilling, fracking and in the return waste water which has to be disposed of. Huge opposition movement in the US and in Australia see for the briefing from the Australian National Toxics Network and the Endocrine Exchange at for Theo Colborn's extensive cover of the health and environment effects of the toxins used Best wishes Morag

MICHAEL CLARJEN-ARCONADA Comment left 21st February 2013 06:06:01
Thank you Prof. Peter Saunders for such a thorough article presenting the fundamental issues affecting hydraulic fracturing. After a careful exposition of the many factors associated with fracking, it seems reasonable to conclude [as many Communities throughout Planet Eatth have resolved (many mentioned above in the article)] that a ban or moratorium must be in place on the use of hydraulic fracturing for the extraction of oil and gas from shale or other ‘tight’ rock formations. On the merits of the case it is clear that FRACKING TECHNOLOGIES MUST BE REJECTED. The risk(s) of environmental and water pollution are to great for their consideration and possible application. Goya, the masterful artist from Spain said: "el sueno de la razon produce monstrous" (the dream/nightmare of reason/reasoning produces monsters). Fracking is such a case. Let us promote educational and legal campaigns (both locally and globally) to empower local communities to implement such fracking ban. Furthermore, let us concentrate on the progresiive development of Ecological Communities Living the Code: Return to the Ecological Garden. It is around the garden that we can design and build simple ecological technologies (clean - renewable - distributed energy systems) that will make such ecological communities self-regulated / self-sufficient and wealthy; completely independent from the slavery of the !% Oppressive- Polluting Energy Corporate Cartel. Please watch video on youtube: concerning Ecological Communities Project - Living the Code: Return to the Ecological Garden. We human beings are fundamentally (75%) water: we are food and water. Optimal foods for human beings are fundamentally seeds and water. We must ensure clean water. We must learn and live the fundamental principles the operate in Nature by the application of the simple Code: Return to the Ecological Garden. All the best, Michael Dr. Michael T. Clarjen-Arconada Natural Biological Medicine INTEGRAL HEALTH CENTER (305) 926 9679 (mobile) USA - US GLOBAL (631) 604 4107 (34) 656 434 443 Spain SKYPE: AMBERWAVESHEALTH WWW.NATURALHEALTHMETHODS.ORG Director of Research and Program Implementation ECOLOGICAL COMMUNITIES PROJECT Coordinator East-End Clean Water Working Group

Charles McEwan Comment left 23rd February 2013 08:08:54
How good is the evidence that global warming is caused by more CO2 in the atmosphere? I understand there is a correlation but is there a cause and effect relationship?

Chanou Comment left 31st January 2014 09:09:50
This was just a fantastic article. After glancing on it, i became exposed in knowing some of the dangers exacerbated by franking. I am from Cameroon, where the number of new wells are growing like mushrooms with no resistance force of opposition due to lack of knowledge by the locals. What makes it worse is that even if they do have such knowledge, they will be suppressed to the fullest by the government if they temper to voice out their concerns. Thanks very much

David Packham Comment left 26th January 2015 05:05:24
Shale gas use incompatible with limiting global warming to "safe" levels? I would like to add a comment, from a specifically U.K. perspective, on Peter Saunders' ISIS Report 20/02/13, Fracking for Shale Gas. The significant use of shale gas, especially for power generation would be incompatible with limiting global warming to "safe" levels. The 2008 Climate Change Act requires that greenhouse gas (ghg) emissions be reduced by at least 80% by 2050, compared to 1990 levels [1]. This reduction is considered necessary in order to keep warming to a "safe" level of a maximum global temperature increase of 2°C since pre-industrial times to prevent dangerous climate change [2]. Informed scientific opinion is worried that Government policy is moving towards a significant additional use of gas for power generation which would make the statutory ghg reduction targets unattainable. These concerns were summarised in a letter written last September by the Climate Change Committee [3]: "We are writing to express the great concern of the Committee on Climate Change about the recent Government statement 'that it sees gas as continuing to play an important role in the energy mix well into and beyond 2030 ... [not] restricted to providing back up to renewables' "Extensive use of unabated gas-fired capacity (i.e. without carbon capture and storage technology (CCS)) in 2030 and beyond would be incompatible with meeting legislated carbon budgets. These are, of course, designed to balance the costs and risks of meeting long-term objectives and they require significant investment in low-carbon power generation over the next two decades ..... Unabated gas-fired generation could therefore not form the basis for Government policy, given the need under the Climate Change Act to set policies to meet carbon budgets and the 2050 target. This does not deny the important medium-term role of gas in meeting our energy needs which is already factored into the budgets (i.e. predominantly for heat in buildings and industry), nor does it prohibit the use of our own gas resources for this purpose, if environmental concerns can be addressed." The committee went on to urge the need "To address this risk, and to buttress the signal provided by carbon budgets, an appropriate approach would be to set a clear carbon objective for the EMR in secondary legislation (to reduce carbon intensity of power generation to around 50 gCO2 / kWh by 2030), as recommended by the Energy and Climate Change Select Committee." The Government has rejected this advice from the Climate Change Committee [4, 5]. It is probably appropriate here to add a personal speculation. Here in Bath and on the near-by Mendips fracking is very much a local issue. A local environment group sought the opinion on the issue of a local M.P., the Hon. Jacob Rees-Mogg. He favours development towards exploitation of shale gas despite the fact that this might be incompatible with meeting carbon targets of the Climate Change Act of 2008. He is prepared to see the carbon reduction targets of the Climate Change Act of 2008 changed to allow increased carbon emissions. Indeed Rees-Mogg appears not to accept the judgement on climate change of the International Panel on Climate Change (IPCC), endorsed by the Royal Society, the U.S. National Academy of Sciences and the leading science academies in most of the world, but finds "attractive" the opinions of the Global Warming Policy Foundation, the secretly funded pressure group led by Nigel Lawson. It is sobering to consider that Rees-Mogg's views could be typical of a significant section of Conservative M.Ps. who, perhaps are simply waiting for the opportunity to abandon the whole commitments to control carbon emissions made under the terms of the Climate Change Act. A report of what Rees-Mogg said to a local environment group can be found here D. E. Packham, Materials Research Centre, University of Bath. 22nd Feb. 2012 References 1. 2. The Royal Society, Preventing dangerous climate change The need for a global agreement, December 2009; Document 12/09 DES1723 3. Committee on Climate Change, The need for a carbon intensity target in the power sector, letter to Secretary of State, Department of Energy & Climate Change, 13.9.12 (on line) 4. 5.