# Fossil Fuels

Category: The A-Z Of Sustainability

## Short Summary
Fossil fuels are energy sources formed from ancient organic matter buried and compressed over millions of years, including coal, oil, and natural gas. While providing most of the world's energy, burning fossil fuels releases stored carbon dioxide, making them the primary driver of climate change.

## Full Definition
What are Fossil Fuels? Fossil fuels are hydrocarbon-based energy sources created from the remains of plants and animals that lived millions of years ago. Through geological processes involving heat and pressure, these organisms transformed into coal, crude oil (petroleum), and natural gas—the three primary fossil fuel types that power modern civilization. These fuels are called 'fossil' because they originate from fossilized organic matter. They are also classified as non-renewable resources because their formation takes millions of years, while current consumption rates will deplete known reserves within decades or centuries. Types of Fossil Fuels Coal - A solid fuel formed from ancient plant matter in swamps and peat bogs. Used primarily for electricity generation and steel production, coal is the most carbon-intensive fossil fuel. Oil (Petroleum) - A liquid fossil fuel refined into gasoline, diesel, jet fuel, and other products. Predominantly used for transportation and as feedstock for plastics and chemicals. Natural Gas - A gaseous fuel composed primarily of methane. Used for heating, electricity generation, and industrial processes. Often marketed as a 'cleaner' fossil fuel, though it still contributes significantly to emissions. Climate Impact Fossil fuels are the dominant driver of climate change, responsible for approximately 75% of global greenhouse gas emissions and nearly 90% of carbon dioxide emissions specifically. When burned, they release carbon that was stored underground for millions of years back into the atmosphere, disrupting Earth's carbon cycle. The combustion of fossil fuels produces not only CO₂ but also other harmful pollutants including sulfur dioxide, nitrogen oxides, particulate matter, and mercury. These contribute to air pollution, acid rain, respiratory diseases, and ecosystem damage beyond their climate impacts. Economic and Energy Dominance Despite growing renewable energy adoption, fossil fuels still supply approximately 80% of global primary energy. This dominance stems from their high energy density, existing infrastructure, established supply chains, and historically low costs that didn't account for environmental externalities. The fossil fuel industry represents trillions of dollars in global economic activity, creating both powerful economic interests and significant employment. This economic entrenchment makes transitioning away from fossil fuels a complex challenge requiring careful management of economic disruption and social impacts. The Transition Away from Fossil Fuels Limiting global warming to 1.5°C requires rapidly phasing out fossil fuel use. The International Energy Agency projects that achieving net-zero emissions by 2050 means no new oil and gas fields can be developed, and coal use must decline sharply within this decade. The energy transition involves replacing fossil fuels with renewable alternatives like solar, wind, and hydroelectric power, improving energy efficiency to reduce overall demand, electrifying transportation and heating systems, developing energy storage technologies, implementing carbon pricing mechanisms, and phasing out fossil fuel subsidies. Success requires coordinated action from governments, businesses, and individuals, along with investments in clean energy infrastructure and support for affected workers and communities through just transition programs.

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Source: Alectro Sustainability Glossary
URL: https://alectro.io/glossary/fossil-fuels
Last Updated: 2025-11-12