Coal: Facts & Figures

Historically the most important and widespread fossil fuel, now seen as an environmental disaster, coal comes in different grades and is mined using several different methods. We explain its history, benefits, effects on climate change and ecological impacts.
Lignite Coal Mine in Poland
Lignite mine “Turów”, Poland. Photo: © Anna Uciechowska

Coal Causes the Worst Pollution of Any Fossil Fuel

Coal is not only the most widespread of all fossil fuels, it’s also the most damaging. Over the past 150 years or so, it has caused significant damage to Earth’s climate system, as well as to the local ecosystems wherever it is mined. It has also cost the lives of millions of coal miners. So, while its energy has produced a vast number of useful benefits, its toxic footprint can be found throughout the world.

Coal is formed from partly decomposed plant material that has been compressed beneath layers of sediment and rock at high temperatures over millions of years. This organic sedimentary rock contains mostly carbon with some hydrogen, sulfur, oxygen, and nitrogen.

The longer the coal has been forming underground, the higher its carbon content, and the less moisture it contains. Anthracite, for instance is roughly 93.5 percent carbon, while lignite is roughly 67.5 percent. The higher the carbon content, the more heat it produces when burned. According to the geological observation known as Hilt’s law, the deeper the coal is found, the higher its carbon content and heating value.

Coal is found on all continents except Antarctica, typically in places where forests and marshes used to exist during prehistoric times. The largest known reserves are located in the United States, Russia, China, India and Australia. Deposits are usually found in the form of layers (coal beds) or veins (coal seams) and can be mined on the surface or below ground. As of 2020, it accounts for roughly 27 percent of the world’s energy demand and produces roughly 36 percent of the world’s electricity. 

Coal accounts for some of the worst pollution effects of any fossil fuel, as well as a history of mining fatalities and lung disease (pneumoconiosis). It is also a significant contributor to global warming because of its greenhouse gas emissions of methane (CH4) and carbon dioxide (CO2). Despite the introduction of a number of cleaner technologies (pulverised coal combustion systems, integrated gasification combined cycle, fluidised bed combustion), as well as carbon capture and storage techniques, the much vaunted “clean coal” has yet to materialize.

“Peak coal” – the point when consumption reaches its maximum, before declining – occurred in 2018, although the drop in 2019 was only around 1 percent. 1 That said, experts believe that demand will continue to fall. 2 This is good news for climate change, although the number of new coal-fired power plants being commissioned by China and India suggests that coal will be emitting greenhouse gases into the atmosphere for decades to come.

Open Cast Mine, Lignite: East Germany
Lignite open-cast mine in Jaenschwalde, East Germany. Photo: © Michael Sohn

Coal Mining: A Very Brief History

According to archeological evidence, the earliest known surface mining occurred around 3490 BC in China 3 and in Wales (UK). The earliest known use of coal in the Americas was by the Hopi Indians, in the 12th century, in what is now the southwestern United States. 4 They used it for domestic heating and cooking and later for industrial pottery making. Other users around this time were the Aztecs of central Mexico. They also used jet, a type of lignite, for ornaments. 5

In Roman Britain, by the late 2nd century AD, the Romans were mining coal from a number of major coalfields. A cross-channel trade duly developed with the Rhineland, where coal was already employed in the smelting of iron ore. 6

Although by the 14th century it was being used for domestic heating in several areas of Britain, it wasn’t until the middle of the 16th century when supplies of wood began to run out that its use as a domestic fuel expanded nationwide. 7

In North America, coal deposits were first unearthed in the 1600s by French traders along the shores of Grand Lake in New Brunswick, Canada. By 1643, they were sending supplies to the British colony at Boston. 8

Although coal production took off in America during the early 19th century, doubling or tripling every decade, followed mid-century by the rapidly increasing output of petroleum, it was British mining during the late 18th century and early 19th century that powered the Industrial Revolution, and inadvertently kick-started our climate crisis through its emissions of CO2 and CH4.

The invention of the steam engine and other production technologies created a massive demand for coal. Coal combustion being more intense than wood burning, it was soon widely used (i) to drive the new steam engines, (ii) to power new plants and industrial machinery, and (iii) to fuel the new steamships. It was actually the global network of ships’ coaling stations that triggered mining around the world.

In 1700, annual output in Britain was about 3 million tons. By 1815 it had grown to 16 million tons and by 1830 it was over 30 million tons. 9 By 1905, Britain still produced about 25 percent of the world’s coal.

In America, too, production was surging. From 8.4 million short tons in 1850, it reached 350 million short tons in 1905 (almost 40 percent of global production), finally peaking at 680 million short tons in 1918, before the Great Depression of the 1930s reduced demand to 360 million tons in 1932. 10 Production recovered and continued to rise for the rest of the century, reaching 1,162.7 million short tons in 2006. (Note: 1 short ton = .907 metric tonnes.)

What Are the Main Alternatives to Fossil Fuels?
The most promising alternatives to fossil fuels, include renewables like hydropower (hydroelectricity), solar power, natural biomass and biofuels, wind power, underground geothermal energy, and (down the road) wave power and tidal energy.

What Are The Main Types Of Coal?


Peat is the least-coalified material. A mixture of partially decomposed plant material (humus), it’s really a precursor to coal. It contains the least carbon and gives off the least heat.


Lignite is the lowest level of true coal. It’s really a peat that has been transformed into a rock, and may contain recognizable plant structures. It has a low carbon and low energy content. In Europe and Australia, lignite is sometimes called “brown coal.”


Sub-bituminous coal is a lignite that has undergone an increased level of organic transformation (compaction and heat processing). This expels some of the oxygen and hydrogen, and produces a fuel with a higher carbon content. On the basis of heating value, it is further classified into sub bituminous A, sub bituminous B, and sub bituminous C.


Bituminous is the most common type of coal. It accounts for about half the coal mined in the United States. Bituminous coal has undergone yet more compaction and heat processing, which gives it a much higher heat value than lignite or sub bituminous types. On the basis of volatility, bituminous types are commonly classified as low-volatile bituminous, medium-volatile bituminous, and high-volatile bituminous. Bituminous coal is often referred to as “soft coal.”


Anthracite is the highest rank of coal. It can contain up to 95 percent carbon and has the best energy content. Unlike other types, it is considered to be a metamorphic rock. Anthracite is often referred to as “hard coal”; however, like the nickname of “soft coal” given to the bituminous type, this has little to do with the hardness of the rock. Anthracite accounts for roughly one percent of world coal reserves 11, and is mined in only a few countries. China has the highest anthracite output, while other producers include: America, Australia, Canada, North Korea, Russia, South Africa, Ukraine, Vietnam. Total production in 2010 was 670 million tons. 12

Carbon/Hydrogen Content & Calorific Value of Coal

Chart: Coal Types & Composition

The most important distinction between the different grades of coal is between (a) thermal coal – more abundant with a lower carbon content – which is burned in power stations to create steam in order to generate electricity; and (b) metallurgical coal (also called coke or coking coal), which is burned inside furnaces at very high temperatures in order to make steel. Coke is produced via pyrolysis (heating in the absence of oxygen) a procedure that removes moisture and other volatile components (such as sulfur gases, propane, benzene and other aromatic hydrocarbons) from the coal, producing a highly carbon-rich material. Metallurgical types are found mainly in Canada, the United States, and Australia.

All You Need To Know About Climate Change
For answers to popular questions, see: 50 FAQs About Global Warming and 50 Climate Change FAQs.

What Are The Main Uses Of Coal?

Lignite is the most harmful to health and is used almost exclusively as fuel for electric power generation. Lignite accounts for 8 percent of U.S. production (2019). 13

Sub-bituminous and bituminous types are used primarily to generate electricity, although the higher-carbon bituminous types are also used to make steel. In the latter case, the bituminous coal must first be “coked” – heated without air to extremely high temperatures – to remove volatile components. Bituminous coal accounts for 48 percent of U.S. production (2019), compared to 44 percent for sub-bituminous.

Anthracite classified as standard grade, is used mainly in power generation, as well as residential and commercial space heating. High grade (HG) and ultra-high grade (UHG) anthracite are used mainly in the metallurgy sector.

Countries With The Largest Coal Consumption (2019)

CountryExajoulesGlobal ShareChange on 2018
South Africa3.82.4%+1.4%
South Korea3.42.2%-5.3%
Source: IEA 2020

How Is Coal Used To Make Electricity?

How Electricity Is Made From Coal: Diagram
How electricity is generated from coal, using a conventional coal-fired power plant. Image: © Kentucky Geological Survey

The generation of coal-fired electricity is a five-step process:

(a) Combustion

Thermal coal (either black or brown) is pulverised to a fine powder. This increases the surface area and allows it to burn more quickly. The powdered fuel is then blown into the combustion chamber of a boiler where it is burned at high temperature (to about 537°C/ 1,000°F).

NOTE: Combustion is the process that emits partially combusted particles of soot, black carbon and gaseous materials, that contribute to smog pollution in cities, causing respiratory and circulatory health problems.

(b) Water Is Turned Into Steam

The heat energy from the combustion is used to turn water – residing in tubes lining the boiler – into high pressure steam.

(c) Steam Spins Turbine

The high-pressure steam (at around 1,800 pounds per square inch) is then directed into a turbine with thousands of propeller-like blades. The steam pushes these blades causing the shaft of the turbine to spin at high speed (about 60 revolutions per second).

(d) Spinning Coils Of Wire Creates Current

An electrical generator, consisting of a series of wound copper wire coils, is connected to one end of the turbine shaft. As the wire coils are rapidly rotated in a strong magnetic field, an electric current (of around 20,000 volts) is created. Meantime, after passing through the turbine, the steam is cooled, condensed back into water and returned to the boiler to be heated once again.

(e) Electricity Transmitted Via Grid

The electricity is transformed into higher voltages (up to 400,000 volts) used for economic, efficient transmission via power line grids and transmitted to the consumer.

A coal-fired power plant that generates around 10 billion kilowatt-hours of electricity a year (enough to supply 700,000 homes), burns about 14,000 tons of coal a day, delivered to the power plant in 140 railway cars.

How Much Coal Do We Produce?

In 2019, global coal production was 7921 mt (million tonnes) an increase of 1.5 percent over 2018. This was half the increase of previous years. 14

China is the world’s biggest producer of coal. It increased 4 percent to 3,693 Mt in 2019. In comparison, the United States continues a falling production trend that started at the beginning of the century, reaching 640 Mt in 2019, the lowest level seen in four decades. 15

Note: (Note: 1 U.S. short ton (st) = 0.907 tonnes.)

In its December 2020 Short-Term Energy Outlook, the U.S. Energy Information Administration forecast that U.S. coal production would total 521 million short tons (MMst) in 2020, a 26 percent decline from 2019. Forecast for coal production rises to 624 MMst in 2021, a 20 percent increase from 2020 levels. EIA expects coal production to grow because of increased coal demand from the electric power sector amid higher natural gas prices in 2021. 16.

Coal accounts for 24 percent of U.S. electricity in 2019, and is forecast to account for 20 percent in 2020 and then return to 24 percent in 2021.

Which Countries Produce The Most Coal?

Top Ten Coal Producers

CountryMillion Tonnes (MT)
South Africa254
Top 10 coal producers in 2019. Much of global coal production is used in the country in which it was produced; only around 15 percent of hard coal production is destined for the international coal market. Source: IEA 2020 15

How Much Coal Do We Have Left?

World coal reserves in 2019 stood at 1070 billion tonnes and are heavily concentrated in just a few countries: US, Russia, Australia and China. At current rates of production, coal reserves should last for 132 years, with North America (367 years) with the highest ratio.

Top 10 Countries With Most Coal Reserves

CountryMillion TonnesGlobal Share
United States24953723.3%
Poland 269322.5%
Top 10 countries with most proven coal reserves in 2019. Source: BP Statistical Review of World Energy 2020

What Effect Does Coal Have On Global Warming?

Coal is still the largest source of greenhouse gas emissions from fossil fuels.

Fossil Fuel CO2 Emissions By Fuel Type
Annual CO2 Emissions from Fossil Fuels. Global energy-related CO2 emissions flattened in 2019 at around 33 gigatonnes (Gt), following 2 years of increases. This resulted mainly from a sharp decline in CO2 emissions from the power sector in advanced economies, thanks to the expanding role of renewable sources (mainly wind and solar PV), fuel switching from coal to natural gas, and higher nuclear power output. Image: © Global Carbon Budget 2019

Like all fossil fuels, coal gives off carbon dioxide (CO2) when burned. It also emits nitrous oxide (N2O). Its production and transport also releases methane 17 a greenhouse gas which is 84 times more powerful than CO2 over a 20-year period. 18 Bottom line: coal is a major contributor to the man-made greenhouse effect and to the effects of global warming around the world.

Life Cycle Emissions From Electricity Power Sources
Source: IPCC 19 20 Image: ©

As shown above, coal-fired power stations give off more greenhouse gases per unit of energy produced than any other electricity source. 21 But see also: Greenhouse Gas Statistics.

How Does Coal Affect The Environment?

Coal is hazardous to humans and the environment throughout its life cycle. Mines frequently become environmental blackspots, with slurry ponds and landfills leeching chemicals into groundwater. For details, see: Environmental Effects of fossil Fuels.

The combustion of coal is linked to a very wide range of environmental and health problems. Air pollution in the form of heat-trapping greenhouse gas emissions that drive global warming, is a major problem. So too is the emission of huge quantities of partially combusted particles – known as particulate matter – and tiny aerosols that can be inhaled deep into the lungs. In developing countries, such as India, coal is a contributor to indoor air pollution from domestic open fires, and also to the vast toxic haze known as the Asian Brown Cloud that materializes during the dry winter months, as well as ground level ozone and smog in urban areas during the same period.

In the United States, coal-fired power stations are also the largest source of atmospheric mercury emissions. 22 See: Health Effects of Air Pollution.

Mining accident in Heilongjiang, China
Coal mining remains one of the most hazardous occupations. In China, for example, due to slowing demand and pit closures the number of mining fatalities declined by 13.1 percent in 2018 to stand at 333. Shown here are Chinese miners and rescuers mourning the loss of colleagues in northeastern Heilongjiang province. Photo: © Toronto Star, 2016

How Many Coal Miners Are Killed Or Injured Each Year?

Coal mining has always been one of the world’s most dangerous occupations. In America alone, more than 100,000 miners died in accidents over the period 1907-2007. The annual death toll among US miners amounted to roughly 1,500 every year until approximately the 1970s. 23 Fortunately, fatalities in US mines between 1990 and 2012 have significantly declined, with fewer than 100 each year. 24

Worldwide, mining remains exceptionally dangerous, although there are still no reliable global statistics available. According to the Geneva-based International Federation of Chemical, Energy, Mine and General Workers’ Unions (ICEM), an estimated 12,000 miners are killed in accidents every year. 25

China, for example, produces around 45 percent of the world’s coal and accounts for about 80 percent of mining fatalities. 26 There were 10,684 deaths in China during the two years 2005-2006. 27 For every 100 tons of coal mined, the death rate in Chinese mines is 100 times that of the death rate in the US and 30 times that in South Africa. What’s more, 600,000 Chinese miners, suffer from pneumoconiosis the fatal (but preventable) lung disease caused by long-term inhalation of coal dust. And the figure increases by 70,000 miners every year. 28

Worldwide, pneumoconiosis led to 260,000 deaths globally in 2013, an increase of 3.5 percent on 1990. 29 In America, where pneumoconiosis has caused 76,000 deaths since 1968, 45 billion dollars have been spent in federal compensation for miners and their dependents. 30

Despite the history of death and disease in the coal industry, only 24 countries have ratified the ILO Safety and Health in Mines Convention — including major industry players such as the United States, Brazil, Peru and South Africa. Countries, such as Chile – the world’s leading copper producer – as well as Australia, Canada, Democratic Republic of Congo, India, Russia and Ukraine are among those who have ignored the 1995 pact.

Job Retraining After Decarbonization

In the United States, as elsewhere, the mining workforce is a fraction of its former number. In 1919, US coal mines employed 694,000 workers. By 2015, only 65,971 workers remained – less than 10 percent of the peak workforce. Furthermore, according to a 2016 study, a relatively minor investment would allow most coal workers to retrain for the solar energy industry. 31

The Need To Decarbonize

In order to stabilize rising temperatures thus avoiding the worst effects of global warming, the vast majority of climate scientists – including the Intergovernmental Panel on Climate Change – have urged governments to replace fossil fuels with renewable energy sources, like solar, wind, hydro and bioenergy – a process known as decarbonization. To this end, the Paris Climate Agreement, signed up to by most nations, laid down goals which require a reduction of 45 percent in global greenhouse gas emissions by 2030, reaching net-zero by 2050.

Unfortunately, these goals now look hopelessly optimistic. As of 2020, with emissions still rising, energy consumption rising and more and more coal-fired power plants being planned and built, a significant “energy gap” is opening up between the amount of renewable power we need to generate by 2050 and the amount we can generate.

To add insult to injury, governments seem incapable of agreeing a joint approach to climate action, despite having already agreed to most of the necessary conditions, as laid out in the UNFCCC (1992).

To understand why governments and fossil fuel companies are so slow to decarbonize, see: Root Cause of Climate Change.

As a result, it seems that only three options remain.

First, we could resort to more nuclear power. It’s a proven source of reliable, low-emission energy. However, it has huge safety problems as well as cost and clean-up issues. For an in-depth article on this topic, please see: Is Nuclear Energy a Replacement for Fossil Fuels?

Second, we could devote extra resources to reducing emissions from fossil fuel power plants, through the use of carbon capture and storage and other technologies. The problem here is twofold. Clean coal looks to be something of a mirage following the recent debacle at Mississippi’s Kemper County Energy Facility. Also, the natural gas industry has so far proved unable to significantly reduce rates of methane seepage from its worldwide network of pipelines and other installations. (See: Why are Methane Levels Rising?) So this option also seems to be implausible.

Our final option is to learn to use less energy. (Think 30-50 percent less.) Would you be willing to slash your energy consumption to save the planet?


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