Short answers, pulled from the story.
Fossil fuels form through the anaerobic decomposition of dead plants and animals buried under heavy layers of inorganic sediment. This process takes millions of years to complete under high temperature and pressure, converting remains into kerogen and then hydrocarbons.
Commercial exploitation of petroleum began in the 19th century after centuries of limited use. Prior to the latter half of the 18th century, windmills and watermills provided energy for work like milling flour or sawing wood before fossil fuels took over.
Over 70% of greenhouse gas emissions due to human activity in 2022 was carbon dioxide released from burning fossil fuels. Natural carbon cycle processes remove only a small part of this excess, leading to a net increase of many billion tonnes of atmospheric carbon each year.
Global air pollution deaths due to fossil fuels reached over 8 million people in 2018. This figure represents nearly one death out of every five worldwide according to health data.
Economists point to energy prices as the main reason for high inflation in recent years because fossil fuel prices drive every big episode of inflation since World War II. Dependence on these fuels is the main driver of the 2021 and 2022 inflation spike.