Naturally occurring gases dispersed in the atmosphere influence the Earth’s climate by trapping solar radiation. This phenomenon is known as the greenhouse effect. Abundant scientific evidence shows that human activities are increasing the concentration of greenhouse gases (GHGs) and changing the global climate. The most significant contributor is the burning of fossil fuels for transportation, electricity generation and other purposes, which introduces large amounts of carbon dioxide and other GHGs into the atmosphere. Collectively, these gases intensify the natural greenhouse effect, causing global average surface and lower-atmospheric temperatures to rise.