Petroleum is a fossil fuel formed from the remains of ancient marine organisms. These remains settled on the sea floor millions of years ago, and sediment piled on top of them over time. High pressure and heat compressed the remains into a mixture called petroleum. The term petroleum usually refers to the liquid form of this mixture. It is also called crude oil or just oil. There is also a gas form of petroleum, called natural gas, and a solid form, called bitumen. Petroleum needs to be processed before people can use it, but then it is used to make many products. However, because it took millions of years to form, petroleum is a nonrenewable resource. It cannot be replaced once it is used up.

Petroleum exists in underground reservoirs. People extract it using drilling machines. These machines can drill deep into the land or even under the ocean. In some situations, drilling operators blast water, sand and chemicals into rocks deep underground to break them apart and release petroleum. This is a process called fracking.

Petroleum can be processed into gasoline to power transportation. Manufacturers also use petroleum to make many items, including tires, refrigerators, clothes, trash bags and antiseptics.

While it’s useful, extraction and use of petroleum harms the environment and humans. Burning petroleum releases carbon, which increases the greenhouse gases in the atmosphere. This is causing the rapid climate change and global warming happening today. Burning oil accounts for around a third of the world’s carbon emissions.

Reserves of petroleum can be found all over the world, but just four countries control more than half of them. As of the mid 2020s, Venezuela had the most oil in reserves at 303 billion barrels. The countries with the most oil reserves after Venezuela are Saudi Arabia, Iran and Canada. Saudi Arabia has 267 billion, Iran has 209 billion and Canada has 163 billion. Around a third of the world’s energy supply comes from oil. The United States, Saudi Arabia and Russia produce the most oil. The United States, China and India consume the most oil.

Uses of Petroleum

Petroleum is a popular source of energy worldwide, particularly for transportation. Oil has high energy density compared to other sources of energy. This means that smaller amounts of oil can provide the same energy as larger amounts of other fuel.

Cars, trucks and other vehicles rely on petroleum products for this reason. About 94% of fuel for vehicles comes from petroleum. A lot of this fuel is gasoline. It is made from crude oil and other petroleum liquids. Transportation is also a major contributor to carbon emissions because of the use of petroleum. Experts estimate that transportation accounts for between 15% and 25% of carbon emissions worldwide each year.

Petroleum-powered products also serve as a backup to electrical power where electricity is unstable or unavailable. Power generators use diesel fuel to run. They can power lights or other devices. Hospitals use generators if electricity goes out during natural disasters. Diesel generators keep computer systems up and running if other power sources go out. However, relying on diesel in emergencies can cause problems.

In 2022, Hurricane Fiona caused massive destruction to the U.S. territory of Puerto Rico. Rural clinics often did not have access to diesel or generators. Many citizens trying to take care of their families in their homes also had no way to get fuel. There were massive lines for diesel. The disaster showed that Puerto Ricans had recurring problems with fuel and electricity access after repeated hurricanes. It also showed the lack of effective federal support from the United States government.

“Those of us who live in the mountains are used to having our water and electricity go out every day. Now, the whole country knows what we go through and nobody does anything,” Shamir Martinez, a resident of a rural area outside San Juan, told the news organization Reuters in 2022. This is one way that relying on petroleum can become negative and harm marginalized communities.

In addition to fuel, petroleum is useful for making other products. Plastic manufacturers use chemicals from fossil fuels to make different kinds of plastics. Some of these items are essential to people’s lives, such as artificial limbs. These chemicals are also used to produce important nonplastic products, like toothpaste, vitamin capsules and crayons.

However, plastic has harmful environmental effects. Discarded plastics break down slowly and fill up oceans and landfills, harming wildlife. Toxins from plastics leach into the environment. They build up in animal and human bodies, potentially causing negative health effects.

Drilling for Petroleum

Drilling petroleum also harms the environment. The drilling process starts with finding oil reserves. Companies find reserves by doing tests that make extremely loud noises that disturb wildlife. Sea creatures that use sound to find mates and hunt, such as whales, stop doing these activities because of the sounds. They can also lose their hearing if they’re too close to the blasts. In some cases, these sounds may even kill animals.

To drill on land, workers must clear the area for industrial use, destroying habitats. Oil wells are holes that are drilled and then used to bring petroleum to the surface. The construction of an oil well can cause migration patterns to change. This happened in the Murchison Falls National Park in Uganda. Experts have noted that animals like elephants are avoiding the oil pipeline that runs through the park, changing where they look for food.

Wells can leak oil and gas into the environment once they are built. Oil leaks can kill animals when they happen, and the damage can affect the environment for decades. This is the case with the Deepwater Horizon oil spill that happened in 2010. The disaster killed tens of thousands of sea turtles and birds, and trillions of fish hatchlings when it happened. More than 10 years later, effects of the spill make the area hard for wildlife and plants to live in. Scientists have noted that the area around the drill has little life compared to surrounding areas.

Drilling is a major contributor to climate change worldwide. Burning petroleum products creates carbon dioxide. Adding this carbon dioxide to the atmosphere contributes to climate change. The process of drilling alone creates about 5.1 billion tons of greenhouse emissions. This is about 15% of the total emissions of the world.

Drilling for petroleum products also poses risks to human health. Working in petroleum extraction is dangerous. People get injured or even die in explosions. Some estimates say that more than two workers in oil fields in the U.S. state of Texas die per month.

In West Texas, oil production is the main industry. An unexpected source of job-related deaths are road fatalities. Workers are pressured to move the product around the area as quickly as possible, making them tired and stressed. This makes car crashes more likely to happen.

Working in oil production doesn’t affect everyone equally. Many of the people working in oil fields in Texas are Latin American and recent immigrants. These people are traditionally marginalized communities in the United States. They are also disproportionately hurt by the danger of working in the oil industry.

People who live near oil wells can also face risks. Pollution from fracking can go into the water and air. Research has shown this type of pollution may cause cancer. Living near certain types of oil and gas development sites can make older people die sooner than those who live elsewhere. Research in the United States has found that historically marginalized groups like Black people, Latin American people and people experiencing poverty are more likely to live near oil and gas wells. They are exposed to negative health impacts more often than groups that are not marginalized.

Indigenous people have also needed to fight to protect their ancestral homelands from the environmental harms of drilling. In the Amazon, Indigenous activists like Luene Karipuna of the Karipuna people are advocating to stop the Brazilian national oil company Petrobras from drilling near fishing areas. The company argues that the drilling will not affect Indigenous groups. Indigenous leaders like Karipuna say their rights are being trampled because Indigenous groups never approved the company’s drilling license.

On a larger scale, demand for oil can lead to restrictive governments and conflicts between countries. Some experts say countries that rely on oil and natural gas production for their economies are often less democratic. They cite Russia, Iran and Venezuela as examples. Control of oil production often leads to conflict or war. One example is the U.S. military strikes against Venezuela in 2026, which let the United States gain control of the Venezuelan oil reserves.

Finally, it is likely that humans will eventually run out of usable oil. Experts say humans will run out of extractable oil in about the 2050s to the 2070s, if current use and technology to extract oil stays the same.

History of Petroleum Use

Use of petroleum products goes back to the ancient world. Civilizations like the Sumerians and the Babylonians recorded that crude oil was seeping out of the ground. They learned that crude oil and bitumen were waterproof and could glue things together. They used petroleum products in construction as mortar.

Later societies found more uses for petroleum. In the Sichuan Valley of China, people in ancient times burned natural gas deposits to heat brine and produce salt. In North America, Indigenous people, such as the Chumash Nation, used bitumen to seal and waterproof their canoes. Around the 7th century, Persian alchemist Al-Razi discovered how to make kerosene from petroleum. Later, kerosene became a common fuel for lighting lamps.

In 1859, Edwin Drake built the first drilled oil well in the U.S. town of Titusville, Pennsylvania. This well was able to reach oil that was formerly inaccessible. Previously, people dug oil wells by hand. Drake’s well used new cable technology to drill. Factories began using the oil during the Industrial Revolution. While oil and other fossil fuels spurred the Industrial Revolution, their use created massive amounts of pollution. This marked the start of human-influenced climate change on Earth.

Drilling the seabed followed soon after drilling on land. The first offshore well was built off the end of a pier in the U.S. town of Summerland, California. It started producing oil in 1897. Today, offshore oil and gas rigs are huge structures. They are like small cities with living quarters for hundreds of workers as well as space for equipment and storage. They can drill wells at depths of 3.2 kilometers (2 miles). Once all the oil has been extracted, the wells are meant to be plugged to avoid environmental contamination. Then they are abandoned.

The invention of offshore drilling has left an impact on marine ecosystems. Some impacts have been positive. For example, ocean wildlife like sponges and corals have populated some abandoned rigs, turning them into reefs that support other aquatic life. Countries like Malaysia have encouraged this practice as a way to revitalize their oceans. However, if not sealed quickly or properly, the wells release harmful toxins into the water and air. Research also shows that offshore wells can emit much higher levels of methane than abandoned wells on land.

Replacements for Petroleum Products

Scientists are developing less harmful replacements for petroleum products that are better for the environment. One of these replacements is bio-oil made from biomass. Biomass is organic waste materials like dead plants from farms or food scraps from cities.

Scientists have also developed a renewable natural gas from biomass. When biomass breaks down and decays, it releases gases. Scientists can harvest and refine these gases to use for generating electricity.

There are also ways to decrease reliance on diesel generators. Implementing solar power could fill the role previously filled by generators in emergencies. Solar panels would be unaffected by fuel shortages in an emergency. Some areas of Puerto Rico had access to small solar panels after Hurricane Fiona in 2022. People using these panels were not affected by the diesel fuel shortages that others had to deal with.

Scientists are also developing replacements for petroleum in asphalt. Traditional asphalt uses bitumen. Bio-asphalt uses plant-based bio-oils instead. Some research has shown that bio-asphalt might work better than traditional asphalt at high and low temperatures.

In addition to new products, international cooperation is key for phasing out petroleum. In 2023, countries attending the United Nations Climate Change Conference agreed to transition away from fossil fuels and invest in renewable energy to cut emissions by 43% by 2030. Actions like the Fossil Fuel Treaty Initiative work to create laws to make sure counties decrease their use of petroleum as they promised. People across the world are working on this goal, but it will take a lot of work to decrease and eventually end the reliance on petroleum products.