greenhouse gases (GHG), greenhouse gas emissions, carbon emissions, emissions

Greenhouse gases are gases in the atmosphere that both absorb and emit radiant heat. Greenhouse gases allow sunlight (solar radiation) to enter the atmosphere where it warms the Earth’s surface, then reradiate this heat back into the atmosphere. Without this heat ‘trapping’ (absorption and radiation of heat by greenhouse gases in the lower atmosphere), the Earth’s global climate would be several degrees cooler. So greenhouse gases in the atmosphere play a critical role in assisting to regulate global temperature and heat to make it conducive for current living creatures and ecosystems on Earth. This is known as ‘the greenhouse effect’.

Emissions generally refer to the release of greenhouse gases into the atmosphere. Greenhouse gas emissions can occur naturally as well as due to human activities (such as burning coal for electricity). 

Primary greenhouse gases include water vapour, carbon dioxide (Co₂), methane, nitrous oxide (N2O), chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs – significant in Australia and generated from aluminium smelting) and ozone.

Please also see:

 

Global warming, enhanced greenhouse effect to gain an understanding of the role of increased greenhouse gas emissions in the atmosphere, and

 

Climate change to gain an understanding of how global warming (enhanced greenhouse effect) can cause changes in climate.