Annual global CO2 emissions by fuel or industry 1800-2021

Since the industrial revolution, the volume of carbon dioxide (CO₂) emitted into the air by human activity has grown exponentially, especially since the second half of the 20^th century. Fossil fuel consumption has become synonymous with industrial development across the globe, however it has had an adverse effect on the earth's climate, causing ocean and surface temperatures to rise at an unsustainable rate, in addition to related problems such as ocean acidification, more frequent of natural disasters, and the destruction of the natural world in the pursuit of these resources. Initially, coal was the most commonly-used fossil fuel and was also the largest polluter, before it was overtaken by oil in the 1960s. Coal emissions then spiked once again in the early 2000s, primarily due to a rise in consumption in China, although oil remains the most-consumed fossil fuel in the world today, it is relatively "cleaner" than coal.

Since awareness of climate change has risen in recent decades, the need for alternative energy sources has come to the fore - while the use of natural gas has risen due to its greater efficiency and lower emissions, nuclear and renewable sources of energy are viewed as a long-term solution to the climate emergency. Despite the recent surge in renewable energy output, the volume of CO₂ emitted into the atmosphere continues to rise in most years, due to the growing global population, increased international trade, and lifestyle demands in both more-developed and developing countries alike.