Carbon emissions are the total amount of carbon dioxide and other greenhouse gases (GHGs) released into the atmosphere. They come from burning fossil fuels such as coal, oil and natural gas, and other human activities such as deforestation.
Our planet’s carbon levels have been rising since the start of the Industrial Revolution, largely due to our burning of fossil fuels. As a result, atmospheric concentrations of CO2 have already increased by 50% from their value at the end of the last Ice Age, bringing us to a level not seen on Earth for 50 million years.
Carbon dioxide is an invisible, odorless, and tasteless gas that forms part of the air around us. Atmospheric concentrations are measured in parts per million, or ppm. When a cold winter day brings in a fresh breeze, the water vapor in our breath can condense into clouds of fog that we see, but that is not due to CO2.
The most important human sources of carbon emissions are electricity generation, transportation and agriculture. The majority of these are produced by combustion of fossil fuels, particularly coal and oil. Transportation emissions come mainly from passenger vehicles, such as cars, trucks, vans and buses, and other ICE (Internal Combustion Engine) vehicles. Emissions from the transport sector are growing faster than those from any other end-use sector, reflecting increasing global demand for fossil fuels.
Other natural carbon emissions include volcanic eruptions, wildfires and the decomposition of organic matter in forests and wetlands. These natural emissions contribute to the Earth’s natural carbon cycle, which can be impacted by climate change.