Greenhouse Effect

Natural phenomenon in which a planet's atmosphere is warmed due to the presence of certain gases that have the ability to trap infrared radiation (heat). On Earth, these gases are mainly water vapor and carbon dioxide (CO2) and, in smaller amounts, methane (CH4), nitrous oxide (N2O) and ozone (O3). The greenhouse effect makes life as we know it possible. However, since the Industrial Revolution in the 19th century, human activity has emitted — and continues to emit — large amounts of greenhouse gases, which are the primary cause of global warming and have huge implications for the future of humankind.