Gold, iron, oil, coal—should we count ourselves
lucky to live on a planet packed with rocky riches? Or
unlucky—because we've arrived at the party too late, when oil wells
are starting to sound like drinks cartons being drained to the dregs?
Among all the resources on Earth's endangered list, oil is the one
that causes most concern; sometimes called liquid gold, it's the fuel
that powers a billion car engines, thousands of
power plants, and millions
of home heating systems. Economists and geologists have been
predicting the end of cheap oil for about a half century;
environmentalists have been flagging the dangers of our
overdependence on fossil fuels (oil, gas, and coal) for just as long.
What will we do when the oil runs out? Ideally,
swap our gas guzzlers for electric cars and replace our dirty coal
power plants with squeaky-clean
solar and wind. But all that takes
years or decades—so what will we do in the meantime? What if we
could squeeze just a little bit more fuel from the planet to
keep us going? That's the basic idea behind fracking
(hydraulic fracturing), a method of blasting high-pressure jets of
water into underground gas and oil deposits to flush out more of
Earth's tricky-to-reach resources. Oil and gas companies see fracking
as an economic lifeline that will keep them in profit a few decades
longer. Environmentalists, however, see it as an environmental
disaster that will tip the planet over the edge into catastrophic
climate change. With the debate over fracking so bad tempered and
polarized, how can we know who's right? Whose arguments do we
believe? Can we really afford to frack? Can we really afford not to?
How do we balance economic arguments against environmental ones?
Should we even try? Let's take a closer look and find out!
Photo: A typical well head installed above the Fayetteville shale of Arkansas. These are the pipes through which the fracking fluid flows down into the ground. Photo by Bill Cunningham courtesy of US Geological Survey.
Fracking's the informal name for hydraulic
fracturing—a self-explanatory term, when you think about it a
little bit. In science and engineering, hydraulics means using
pressurized water to power machines like diggers and
cranes. If a jet of water can help a bulldozer shift rocks, maybe it can do other
useful things too. If you shoot it down a gas or oil well, the sheer
pressure will crack apart (fracture) the rocks inside, releasing
trapped oil and gas that can flow to the surface and be captured.
Some of these tricky deposits are buried in tough-to-reach places
that we can't easily drill down to. That's why fracking is very often
used with another relatively modern oil exploration technique called
horizontal drilling (also called directional drilling). Unlike in a traditional oil
well, where the drill string (the spinning pipe that carries the
drill bit deep underground) sinks more or less straight down,
horizontal drilling allows the entire string to bend through sharp
angles to access oil and gas fields located off to the side. (Another advantage is that one drilling rig on the surface can be used to drill a number of different horizontal wells in different directions.) Working hand-in-hand, fracking and horizontal drilling have made it possible
to exploit three relatively inaccessible types of geological deposit
from which oil and gas are otherwise hard to recover: shale gas
(natural gas locked in shale formations), coalbed methane (CBM)
deposits (the methane gas that naturally occurs in coalfields—once considered a dangerous nuisance, but now seen as a useful resource), and tight sands (sandstone and limestone rocks in which
natural gas is tightly trapped).
How does fracking work?
Fracking starts with a well (1) bored several thousand
meters vertically through aquifers (groundwater rocks, 2), and then horizontally into
an oil or gas deposit (3). Once the hole's been drilled, it's cased
with a continuous steel pipe sunk down (and then sideways) the entire
length of the hole, which is cemented into place to make a kind of
giant "drinking straw" through which oil and gas can be
extracted (4). A special perforation gun is lowered down through
the pipe and small explosive charges make holes at various points so the fracking fluid can
be pumped in at high pressure, from trucks on the surface (5). This creates many small cracks in the deposit through which the trapped oil or gas can escape (6).
Although the name "hydraulic" fracturing suggests only water is used, fracking fluid actually contains three main
Water—anything from a few tens of thousands of gallons to millions of gallons per well, which does the fracturing.
Proppant—gritty sand or small ceramic balls that lodge in the fractured rock,
holding the cracks open so oil or gas can flow through. The water and proppant typically make up around 99 percent of fracking fluid. The yellow dots in the artwork above, at stage 6, represent the proppant.
Fracking chemicals—including lubricating and gelling agents and antimicrobial chemicals. These help to carry the proppant and improve the quantity and quality of oil or gas recovered. They usually account for less than 1 percent of fracking fluid.
Photo: Fracking fluid is blasted into the ground through holes perforated in the base of the pipe sunk into the well. Photo by Bill Cunningham courtesy of US Geological Survey.
Once the rock is fractured, pumping stops, so the pressure is released. The gas or oil trapped underground flows back to the surface with some of
the water and chemicals from the fracking fluid and other deposits
flushed up from underground, making up what is technically called
flowback. Fracking can also release what's called produced water
("released water" might be a better name for it), which is
naturally occurring water trapped in something like a shale
formation. Produced water also carries trapped minerals, naturally
radioactive materials, and so on. Since flowback and produced water
both potentially contain toxic chemicals and flushed out salts and
other harmful substances, they're classed as contaminated wastewater.
Some of this toxic mix might be reused on other fracking operations, while the rest must be treated and stored since it's too contaminated to be released into rivers or seas.
The benefits of fracking
At first sight, fracking is a classic example of development that pits economic
arguments (benefits) against environmental ones (costs). That makes
the debate very emotive and difficult to settle: how do you argue
that apples (economic benefits) are better than pears (environmental
benefits) when they're totally different things? As we'll see
shortly, that's a huge oversimplification because some of the
environmental arguments against fracking are actually economic ones,
while some of the economic benefits of fracking are also (according
to the oil and gas companies) environmental benefits too. But let's
try to keep things simple by looking at the economic side of things
first, before moving onto the environmental issues afterward.
Photo: Not all our fuel can be pumped out of the ground as easily as with this "nodding donkey." Fracking can help extend our oil and gas reserves, bringing tremendous economic benefits—but at what cost? Photo by Carol M. Highsmith courtesy of The Lyda Hill Texas Collection of Photographs in Carol M. Highsmith's America Project,
Library of Congress, Prints and Photographs Division.
The biggest argument in favor of fracking is that it helps the oil and gas industry to
recover more fossil fuels at a time when the world's supply appears
to be peaking. In the United States alone, fracking has produced tens
of billions of dollars worth of shale gas in the last few years: over
half of all natural gas produced in the United States in 2015
came from shale deposits; by 2018, thanks to shale, the United States
was producing 90 percent of its own natural gas; and, by
2021, horizontal drilling and fracking of shale formations made up 79 percent of all US natural gas production.
After a long period of decline, by 2013, the United States was the world's biggest natural
gas producer, and as of 2022 generates just under a third (23.1 percent) of the entire planet's gas supply (significantly ahead of Russia's 17.4 percent).
That's helped to knock down the
price of US natural gas by about a quarter to a third in the last few
The United States has also seen a massive increase in
domestic oil production, which has bounced back from a 30-year
decline to the kind of levels that haven't been seen since 1973,
again largely thanks to fracking of shale.
create jobs—and it's no coincidence that the booming US oil and gas
extraction industry created a million new jobs between 2007 and 2012 alone
(though employment levels have fallen significantly since then).
Chart: World natural gas production by country. Thanks to fracking, the United States
(top left, blue slice) now leads world production. Based on 2021 data from
Statistical Review of World Energy, BP, 2022, p30.
Why does it matter where our fuel comes from? Oil powered the 20th-century economy, just
as coal fueled the steam-powered 18th and 19th centuries. In recent
decades, oil production has been dominated by countries in the Middle
East, a politically unstable region, while much of the world's gas
comes from Russia. Many people worry over the risk
of sourcing oil from volatile countries like Iraq (though, of course,
such places are unstable partly because of the huge oil deposits they
control). If gas-guzzling nations such as the United States can
produce more of the fuel they use without relying on expensive
imports, that can only be a good thing: it makes for better "fuel
security" at home and a more secure, less volatile world beyond: if
people have their own oil, they're less likely to fight wars over
other people's—or so the argument goes. (One often-overlooked
counter-argument is that while the US imports huge amounts of oil,
much of US fracking is producing natural gas—an entirely different fuel that can't replace imported oil.)
From transporting goods to heating office blocks, energy adds costs to every product
and service, so cheaper energy has knock-on economic benefits that go
far beyond the petroleum industry. But despite the well-known laws of
supply and demand, more gas and oil doesn't always, automatically,
translate into lower energy prices. While energy consumers have
certainly noticed a difference in the United States, experts believe
that a planned large-scale expansion of fracking in the UK is
unlikely to have any effect on home gas prices. That's partly because
the UK is geologically more complex, so the oil and gas will be more
expensive to recover, but also because Britain is part of a huge
European gas market—and fracked gas will represent only a tiny
proportion of the total.
Some believe the growing competitiveness of renewable energy will
also undermine the economic case for fracking.
Photo: A typical shale drilling rig in southwestern Pennsylvania. Photo by Ken Skipper courtesy of
The costs of fracking
Environmentalists have been quick to challenge the
economic arguments for fracking on economic grounds, but they
can also point to a whole raft of other objections. The three biggest
concerns center on greenhouse gas emissions (the release of gases
that cause climate change), water use, and pollution.
By far the biggest problem is that fracking
enlarges the world's supply of fossil fuels at a time when there is
universal scientific agreement that we need to bring about a
"substantial and sustained reduction" in global carbon dioxide
emissions (current estimates suggest we need to cut emissions to about half their 2010
levels by 2030 and to "net zero" by 2050).
 According to a recent study by Christopher McGlade and
Paul Ekins of University College London, if we're to avoid dangerous
climate change, "globally, a third of oil reserves, half of gas
reserves and over 80 per cent of current coal reserves should remain
unused"—in other words, most of the fossil fuel buried in the
ground must stay there.
 If we accept that analysis, there's no
obvious reason for fracking hard-to-access oil and gas deposits. And
the emissions argument doesn't stop there. Apart from increasing
carbon dioxide emissions by boosting the supply of fossil fuels,
the fracking process can also release trapped methane (a much more potent greenhouse gas)
whether the oil or gas released at the same time is ever burned or not.
Oil and gas producers have a ready reply for the
emissions argument. If we generate more natural gas by fracking, we
could reduce our dependence on coal, a much dirtier fuel that
typically produces twice as much CO2 (and a great deal more sulfur
and nitrogen oxide pollution) when it's used for electricity
generation, according to the US Environmental Protection Agency.
For that argument to hold, the fuel that fracking generates must
displace coal and not more expensive, zero-emission renewable
energy; also, it mustn't add to the total amount of fossil fuel
that's burned (so it mustn't be burned as well as the coal
it's claimed to replace, but instead of it). If methane leaks out
from fracking wells, the CO2 benefit disappears, according to a study by Cornell University Professor Robert Howarth and his colleagues: "Compared to coal, the footprint of shale gas
is at least 20 percent greater and perhaps more than twice as great
on the 20-year horizon and is comparable when compared over 100
 The whole argument gets even more complex when we
consider that coal produces sooty particulates (in the short term)
that slows down the warming it produces. That means fracked gas may
have a worse short-term effect on emissions than coal,
according to Tom Wigley of the US National Center for Atmospheric
, which is disastrous for the climate: emissions cuts
need to happen now, not in decades time when it's too late.
So... fracked gas or coal? Environmentalists
consider both options unacceptable. If we have to avoid
drastic climate change by lowering emissions, the quickest and best
way to do that is to shift away from fossil fuels altogether in favor
of clean renewable energy and energy efficiency, not to engage in complex juggling tricks over which dirty fossil fuel is the "least worst" option.
Emissions are only one of many environmental
objections to fracking. Remember that the basic principle
is to fire powerful jets of water down wells to boost our
"endangered" supply of oil and gas? But water itself is now a
scarce resource in many regions. According to the United Nations:
"2.3 billion people live in water-stressed countries, of which 733 million live in high and critically water-stressed countries." About 4 billion (half the world's population) experience severe water scarcity
for at least one month a year.
 Even in the
United States, people are relying increasingly on disappearing
groundwater supplies—posing critical shortages in states such as
California, Kansas, and Texas already.
 So it could be argued that
fracking simply swaps one problem for another.
Is that scaremongering or a wild exaggeration?
Is our need for water trivial compared to our need for
oil and gas? Perhaps not. According to the US EPA, "approximately
35,000 wells are fractured each year across the United States... the
annual water requirement may range from 70 to 140 billion gallons...
equivalent to the total amount of water used each year in... about 1
to 2 cities of 2.5 million people."
 It takes up to 350,000
gallons of water to frack a coalbed methane formation and as much as
five million gallons to frack a shale deposit. Anywhere from 20–90 percent
of the fracking fluid (the median amount is 70 percent or more) remains underground (the exact amount depends
on the geology and site conditions), while the remainder is
contaminated when it returns to the surface and may still, in
effect, be lost forever.
 Heavy water use in a water scarce world
is a serious issue. The same issue applies to the sand that's often
used as the proppant in fracking fluid: though anything but
rare, it has to be mined or quarried from somewhere, opening up a
further set of environmental impacts—from landscape destruction to
the energy that diggers and trucks use in mining and transportation.
Photo: Wastewater contained in a pond at a fracking site.
Photo by Bill Cunningham courtesy of US Geological Survey.
The quality of the water that spews back up
from wells gives just as much concern as the quantity fired
down them in the first place. Although chemicals make up only a
minuscule fraction of the fracking fluid, the huge volumes of liquid
used mean that, in absolute terms, very large amounts of
water-polluting substances can be used in each well. The exact
constituents of fracking fluid vary from well to well, according to
the geology of the location, and are frequently kept secret for
reasons of commercial confidentiality, but they typically include a
toxic cocktail of acids, carcinogenic hydrocarbons, and volatile
organic compounds (VOCs).
 In all, several hundred different
chemicals are known to have been used in fracking fluid; as an added
headache, the high-pressure fracking fluid flushes other minerals up
from the ground, including toxic "heavy metals" such as lead and
radioactive rocky waste (sometimes named NORM—naturally
occurring radioactive material). All this wastewater has to go
somewhere. As we've already seen, the majority of fracking fluid
usually remains underground, where anti-fracking campaigners believe
it may threaten aquifers (the underground "rivers" that supply
our drinking water); the rest returns to the surface,
where it can pose a risk to soil, rivers, lakes, or other surface
waters, if it spills or leaks from tanks, ponds, or containers.
The oil and gas companies who carry out fracking
point out that aquifers lie relatively close to the surface
(typically about 30–60m or 100–200ft), while oil and gas deposits are
much deeper down (1500–2000m or 5000–6000ft), so the risks of
contamination are smaller than might be expected. They also point out
that they go to great lengths to seal wells with steel and concrete
casing (sometimes multiple layers of it). Although the frackers claim that there have no cases of groundwater contamination to date, those
claims are hotly disputed by local people living near wells who
report water contamination. Even if there has been no contamination
to date, it's impossible to be certain that none of the polluted fracking fluid that will be used in the many thousands of planned wells will ever leak into groundwaters at any point in
the future. The whole point of fracking is that it drastically
disrupts the geology underground so oil and gas can flow more freely.
And if it disrupts the ground that much, the environmentalists argue,
doesn't that raise a significant possibility of contamination?
Studies of 141 Pennsylvania drinking water wells by Robert Jackson
from Duke University, and his colleagues, appear to confirm this:
"Overall, our data suggest that some homeowners living <1 km
from gas wells have drinking water contaminated with stray
 In December 2016, following a long and exhaustive study,
the US EPA finally concluded that fracking has indeed led to
some drinking water contamination.
Contaminated water isn't the only form of pollution
that occurs near fracking sites. The drilling and piping equipment
used in oil and gas fields inevitably leaks some toxic, volatile
hydrocarbons into the air, causing air pollution in local
communities. Tanks and lagoons where flowback from wells is stored
can also give rise to air pollution.
Water and air pollution raise a whole series of
concerns, from the effects on ecosystems to the possible harm to
human health—everything from respiratory illnesses and
skin complaints to miscarriages and birth defects. And it's not just local communities, often portrayed as
self-interested NIMBYs, who are at risk. Around 140,000 people work in
the oil and gas extraction industry in the United States alone
(about 60 percent of them in production or nonsupervisory roles), and
these are the people most at risk from direct contact with toxic
chemicals or inhalation of air pollution.
Photo: Fracking can be hugely disruptive to local communities. This is a typical fracking operation, with dozens of trucks and tankers parked at a Marcellus shale gas field in Pennsylvania. Photo by Doug Duncan
courtesy of US Geological Survey.
Justified or not, a variety of other concerns have
been raised about fracking. When gas company Caudrilla sunk fracking wells in the English county of Lancashire,
prompting a number of small earthquakes, there were howls of protest over
safety; earthquakes in Canada have also been attributed to fracking.
What if deep drilling damaged people's homes or offices?
Who would pay? There are property rights issues too. If wells are
bored horizontally, directly underneath someone's home, doesn't that
person have a legitimate right to claim any oil or gas found there?
What about all the heavy trucks needed to cart equipment and supplies
through the towns and villages where wells are being sunk?
How will that affect the quality of life in local communities? And, with all that highly volatile oil and gas moving around, what about safety? Fears were heightened in 2013 when a freight train hauling 72 wagons of fracked crude oil crashed and exploded at Lac Mégantic in Canada, killing 47 people and demolishing 40 buildings.
Economy versus environment?
Most environmentalists see fracking as a dangerous
distraction from the urgent need to reduce emissions and shift our
society away from what they describe as its "addiction" to fossil
fuels. But is the issue really so black and white? All of us rely on
transportation and home heating: fossil fuels still provide over 80
percent of our total energy.
 Even if you heat your home
sustainably and walk or cycle wherever you go, you still buy shoes,
clothes, TVs, toys, and all manner of gadgets made in
energy-intensive factories and shipped halfway round the world. Even
if you never buy a thing, you still keep your money in a bank that
(in all probability) invests in oil and gas companies. Maybe you go
to school (or send your kids there) in big old buses powered by
gas-guzzling diesel engines? Perhaps all you ever do is read
books—but even they have to be printed and transported. Everything
has an energy impact: however hard you try, it's very hard not to
consume energy every day of your life. And even if you could
succeed in living a squeaky clean and green life, it's very sobering
to remember that there are over seven billion more people packed
tight on Earth. Most of them have higher priorities than
saving the planet—and most of those priorities (running a home,
building a business, raising a family) use large amounts of energy.
In short, in a world so heavily dependent on fossil fuels, there are
very compelling economic reasons for trying to boost supplies of gas
Photo: There are over a billion cars on the planet, most powered by gasoline (petrol). Once easy-to-reach petroleum fields have been exhausted, where will tomorrow's oil come from, if not from fracking shale and other hard-to-reach deposits?
But the trouble with climate change is that we
can't see or even imagine the damage it may cause years, decades, or
centuries into the future. What if large parts of the planet become
completely unliveable? What if entire low-lying islands disappear to
rising seas? What if hugely important cities like New York and London
suddenly find themselves underwater? What if millions of people die
horrible, lingering deaths through droughts, floods, or heatwaves? No-one can imagine a future
of runaway climate change—and most of us, still sunk in denial, do
our best not to try.
When there's overwhelming scientific agreement that burning fossil fuels is threatening climate catastrophe, why
would we possibly want to raise the stakes by fracking oil and gas
deposits so we can burn even more? With a few years of intensive
effort—an Apollo program for the planet—we could substantially
increase the energy efficiency of our buildings, transportation, and
electricity production. If we could shift away from fossil fuels
entirely so 80 percent of our energy came from renewables instead,
there would be no need to pursue fracking or put our future on Earth
at risk. Investment in renewables and efficiency would create jobs,
just like fracking, and lower business costs, just as fracking (in a
best-case scenario) is claimed to do.
Though the heated debate over fracking is sure to
continue, it's far from certain that economic arguments must always trump environmental ones.
Environmentalists argue that we don't have to choose between jobs and planet, oil wells and green fields, clean air and economic
prosperity: for greens, it's a specious argument and a false choice when the
real—and only choice—is between the survival of humankind and
a climate catastrophe. But even environmentalists drive cars, wear shoes shipped
from China, go to school in diesel buses, and
seek treatment in energy-hungry hospitals fired by fossil fuels.
The circle has to be squared somehow—and quickly: we have to meet humankind's ever-growing energy needs
without destroying the planet on which we all depend. And time is running out.
↑Statistical Review of World Energy, BP, 2022, p29. For 2022, the United States produces about 934 billion cubic meters of natural gas, or 23.1 percent of world natural gas production.
↑ The EIA chart US Price of Natural Gas Delivered to Residential Customers (displayed as an annual average) shows a
decline in price from a peak of $13.89 per thousand cubic feet in
2008 to $10.38 per thousand cubic feet in 2015, $10.6 per thousand cubic feet in 2019,
and $10.84 per thousand cubic feet in 2020: a fall of about 25%.
For commercial customers,
the decline was from $12.23 in 2008 to $7.88 in 2017, $7.64 in 2019,
and $7.48 in 2020: a fall of about 39 percent.
The situation has changed somewhat in 2021 and 2022, due to other global events, but the
main point still stands: fracking has led to a dramatic fall in prices.
↑ "Compared to the average air emissions from
coal-fired generation, natural gas produces half as much carbon
dioxide, less than a third as much nitrogen oxides, and one percent
as much sulfur oxides at the power plant." Natural Gas, US Environmental Protection Agency, September 25, 2013. [Archived via the Wayback Machine.]
↑Statistical Review of World Energy, BP, 2022, p9 gives 82.3 percent of "primary energy consumption" as oil, natural gas, and coal (down from 84.3 in 2020, 84.7 percent in 2019 and 85.2 percent in 2018); 13.5 percent for hydroelectricity and other renewables (up from 11.4 in 2020, 10.9 percent in 2019 and 10.4 percent in 2018); and 4.3 percent for nuclear (the same as 2020, slightly down on 2019 and 2018). What about a historical comparison? In 1973, coal, natural gas, and oil provided 86.7 percent of the world's "total primary energy supply"; in 2014, the same fossil fuels were still providing 81.1 percent of our energy. A big hefty expansion of nuclear power and a small increase
in renewables accounts for the difference. Key World Energy Statistics 2016, International Energy Agency, p6. [PDF format, archived via the Wayback Machine].
This Changes Everything: Capitalism Versus the Climate by Naomi Klein. Simon and Schuster, 2014. A more general eco book, but with quite a lot of coverage of how community-led battles over fracking have helped to reenergize the global environment movement's campaign to stop climate change.
Habitat Havoc: Fracking by Ryan Nagelhout. Gareth Stevens, 2014. A simple 32-page introduction, in library binding, for ages 9–12.
Earth Matters by Lynn Dicks et al. Dorling Kindersley, 2008. A simple introduction to the issues currently facing planet Earth, best for ages 8–10. Although fracking isn't covered, there's plenty of coverage of climate change.
Animation of Hydraulic Fracturing (fracking) by Marathon Oil Corporation. A 6-minute animated explanation of the fracking process. Remember that it's essentially company PR, so it glosses over the environmental and safety issues.
Fracking Hell: The True Cost of America's Gas Rush by LinkTV: EarthFocus. This longer, 17-minute news piece is unapologetically anti-fracking and focuses on local community concerns in Pennsylvania. There are some revealing interviews with
academics, campaigners, locals, and an ex fracking worker, though
there are no contributions from the energy companies themselves
(beyond a simple statement of rebuttal read out in a voiceover).
The Facts on Fracking by Susan Brantley and Anna Meyendorff. The New York Times, March 13, 2013. According to the academic authors of this fairly balanced article, "decisions should be based on existing empirical evidence and fracking should be evaluated relative to other available energy sources."
Benefits of hydraulic fracking by Kevin A. Hassett and Aparna Mathur, Oxford Energy Forum, April 4, 2013. A summary of the direct and indirect benefits to the US economy.
Fracking's Future by Michael B. McElroy and Xi Lu. Harvard Magazine, January-February 2013. Exploring the economic arguments and the role that fracking might play on the path to a low-carbon future.
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