The greenhouse effect is a natural warming process of the earth. When the sun's energy reaches the earth some of it is reflected back to space and the rest is absorbed. The absorbed energy warms the earth's surface which then emits heat energy back toward space as longwave radiation. This outgoing longwave radiation is partially trapped by greenhouse gases such as carbon dioxide, methane and water vapour which then radiate the energy in all directions, warming the earth's surface and atmosphere. Without these greenhouse gases the earth's average surface temperature would be about 33 degrees Celsius cooler.

Human activities such as deforestation and the burning of fossil fuels have increased the concentrations of greenhouse gases in the atmosphere. Scientists are concerned that higher greenhouse gas concentrations will lead to an "enhanced" greenhouse effect which may lead to global climate change. The Intergovernmental Panel on Climate Change (IPCC) is an international group of scientists which advises policymakers on the latest science of greenhouse climate change. In late 1995, the IPCC concluded that "the balance of evidence suggests a discernible human influence on global climate."

Research institutes such as the Bureau of Meteorology Research Centre and CSIRO Division of Atmospheric Research use complex computer model simulations of the climate system to investigate potential greenhouse climate changes.