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How does burning fossil fuels change the composition of Earth’s atmosphere?

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Wispy cirrus clouds stretch across a bright blue sky above trees and a river at Pinawa Dam Provincial Park in Manitoba, Canada, with sunlight illuminating the scene. — Atmosphere The atmospheres of planets in the solar system are composed of various gases, particulates, and liquids. They are also dynamic places that redistribute heat and other forms of energy. On Earth, the atmosphere provides critical ingredients for living things. Here, feathery cirrus clouds drift across the deep blue sky over Pinawa Dam Provincial Park, near Pinawa, Manitoba, Canada.

The combustion of fossil fuels significantly alters the composition of Earth’s atmosphere by increasing the concentrations of greenhouse gases, which are responsible for trapping heat and driving global warming.123

Since the Industrial Revolution, human activities—primarily the burning of coal, oil, and natural gas—have released vast quantities of carbon dioxide (CO₂) into the air. This anthropogenic carbon load exceeds the capacity of natural "sinks," such as vegetation and oceans, to remove CO₂ from the atmosphere. Consequently, atmospheric CO₂ levels have risen from preindustrial levels of approximately 280 parts per million (ppm) to over 400 ppm in the 21st century.435

In addition to CO₂, fossil fuel use contributes to the rise of other potent greenhouse gases, including methane and ozone. By absorbing infrared radiation and reradiating it back to the surface, these gases enhance the natural greenhouse effect, leading to an increase in Earth's near-surface mean temperature. Addressing this shift is a critical ethical imperative, as the resulting climate change poses significant risks to global ecosystems and human societies.1523