What is a fossil fuel?

Sulfur dioxide emitted from the combustion of fossil fuels like coal, petroleum, and other factory combustibles are one the major cause of air pollution. Pollution emitting from vehicles including trucks, jeeps, cars, trains, airplanes causes an immense amount of pollution. We rely on them to fulfill our daily basic needs of transportation.

Decomposing plants and other organisms, buried beneath layers of sediment and rock, have taken millennia to become the carbon-rich deposits we now call fossil fuels. These non-renewable fuels, which include coal, oil, and natural gas, supply about 80 percent of the world’s energy. They provide electricity, heat, and transportation, while also feeding the processes that make a huge range of products, from steel to plastics.

When fossil fuels are burned, they release carbon dioxide and other greenhouse gases, which in turn trap heat in our atmosphere, making them the primary contributors to global warming and climate change.

But, their overuse is killing our environment as dangerous gases are polluting the environment. Carbon Monoxide caused by improper or incomplete combustion and generally emitted from vehicles is another major pollutant along with Nitrogen Oxides, that is produced from both natural and man-made processes.

Major types of fossil fuels

There are several main groups of fossil fuels, including:


Black or brown chunks of sedimentary rock that range from crumbly to relatively hard, coal began to form during the Carboniferous period about 300 to 360 million years ago, when algae and debris from vegetation in swamp forests settled deeper and deeper under layers of mud. Mined via surface or underground methods, coal supplies a third of all energy worldwide, with the top coal consumers and producers in 2018 being China, India, and the United States. Coal is classified into four categories—anthracite, bituminous, sub-bituminous, and lignite–depending on its carbon content.


Crude oil, a liquid composed mainly of carbon and hydrogen, is often black but exists in a variety of colors and viscosities depending on its chemical composition. Much of it formed during the Mesozoic period, between 252 and 66 million years ago, like plankton, algae, and other matter sank to the bottom of ancient seas and was eventually buried.

Petroleum use accounts for nearly half the carbon emissions in the U.S. and about a third of the global total. In addition to the air pollution released when oil is burned, drilling and transport have led to several major accidents, such as the Exxon Valdez spill in 1989, the Deepwater Horizon disaster in 2010, the devastating Lac Megantic oil train derailment in 2013, and thousands of pipeline incidents. Nonetheless, oil demand continues to rise, driven not only by our thirst for mobility but for the many products—including plastics—made using petrochemicals, which are generally derived from oil and gas.

Natural gas:

An odorless gas composed primarily of methane, natural gas often lies in deposits that, like those for coal and oil, formed millions of years ago from decaying plant matter and organisms. Both natural gas and oil production have surged in the U.S. over the past two decades because of advances in the drilling technique most people know as fracking.

Natural gas is cleaner than coal and oil in terms of emissions but accounts for a fifth of the world’s total, not counting the so-called fugitive emissions that escape from the industry, which can be significant. Not all of the world’s natural gas sources are being actively mined. Undersea methane hydrates, for example, where gas is trapped in frozen water, are being eyed as a potential gas resource.

Land degradation

Unearthing, processing, and moving underground oil, gas, and coal deposits take an enormous toll on our landscapes and ecosystems. The fossil fuel industry leases vast stretches of land for infrastructures such as wells, pipelines, access roads, as well as facilities for processing, waste storage, and waste disposal. In the case of strip mining, entire swaths of terrain—including forests and whole mountaintops—are scraped and blasted away to expose underground coal or oil. Even after operations cease, the nutrient-leached land will never return to what it once was.

As a result, critical wildlife habitat—land crucial for breeding and migration—ends up fragmented and destroyed. Even animals able to leave can end up suffering, as they’re often forced into less-than-ideal habitat and must compete with existing wildlife for resources.


Burning Fossil Fuels have these consequences:


Global warming pollution

When we burn oil, coal, and gas, we don’t just meet our energy needs—we drive the current global warming crisis as well. Fossil fuels produce large quantities of carbon dioxide when burned. Carbon emissions trap heat in the atmosphere and lead to climate change. In the United States, the burning of fossil fuels, particularly for the power and transportation sectors, accounts for about three-quarters of our carbon emissions.

Other forms of air pollution

Fossil fuels emit more than just carbon dioxide when burned. Coal-fired power plants singlehandedly generate 42 percent of dangerous mercury emissions in the United States, as well as two-thirds of U.S. sulfur dioxide emissions (which contribute to acid rain) and the vast majority of soot (particulate matter) in our air. Meanwhile, fossil fuel-powered cars, trucks, and boats are the main contributors to poisonous carbon monoxide and nitrogen oxide, which produces smog (and respiratory illnesses) on hot days.

Reducing emissions from fossil fuels

Governments around the world are now engaged in efforts to ramp down greenhouse gas emissions from fossil fuels to prevent the worst effects of climate change. At the international level, countries have committed to emissions reduction targets as part of the 2015 Paris Agreement, while other entities—including cities, states, and businesses—have made their commitments. These efforts generally focus on replacing fossil fuels with renewable energy sources, increasing energy efficiency, and electrifying sectors such as transportation and buildings.

However, many sources of carbon emissions, such as existing power plants that run on natural gas and coal, are already locked in. Considering the world’s continuing dependence on fossil fuels, many argue that in addition to efforts aimed at replacing them, we also need to suck carbon from the air with technologies such as carbon capture, in which emissions are diverted to underground storage or recycled before they reach the atmosphere. A handful of commercial-scale projects around the world already capture carbon dioxide from the smokestacks of fossil fuel-fired plants, and while its high costs have prevented wider adoption, advocates hope advances in the technology will eventually make it more affordable.

Building a Clean Energy Future

We’re not locked into a fossil fuel future, however. We’ve made major progress in scaling up renewable energy and energy efficiency in the United States over the past decade, thanks to federal, state, and local policies that have helped to grow the clean energy economy. We’re also using energy much more efficiently than we used to.

State and federal incentives, along with falling prices, are pushing our nation—and the world—toward a cleaner, renewable energy sources such as wind and solar. Renewables are on track to become a cheaper source of energy than fossil fuels, which is spurring a boom in clean energy development and jobs. Significantly higher levels of renewables can be integrated into our existing grid, though care must be taken to site and build renewable energy responsibly.

Meanwhile, energy efficiency is our cleanest, cheapest, and largest energy resource, contributing more to the nation’s energy needs over the past 40 years than oil, coal, natural gas, or nuclear power. It accounts for more than 2.2 million U.S. jobs—at least 10 times more than oil and gas drilling or coal mining.

If we can put the right policies in place, we are poised to make dramatic progress toward a clean energy future. A recent NRDC report finds that we can slash U.S. fossil fuel use by 80 percent by 2050. To do that, we will need to cut energy demand in half, grow renewable energy resources so that they provide at least 80 percent of our power, electrify almost all forms of transportation, and get fossil fuels out of our buildings. That will require sustained, coordinated policy efforts from all levels of government, the private sector, and local communities. But we know we can do it using the proven, demonstrated clean energy technologies that we have today.