Animals, particularly livestock like sheep and cattle, produce methane, a greenhouse gas. When livestock are grazed at a large scale, as in Australia, the amount of methane produced is a big contributor to global warming. Some fertilisers that farmers use also release nitrous oxide, which is another greenhouse gas. Australian farming contributes 16% of our total greenhouse gas emissions.

When we burn fossil fuels like coal, oil and gas to create electricity or power our cars, we release CO2 pollution into the atmosphere.

CO2 survives in the atmosphere for a long time—up to many centuries—so its heat-trapping effects are compounded over time. Of the many heat-trapping gases, CO2 puts us at the greatest risk of irreversible changes if it continues to accumulate unabated in the atmosphere—as it is likely to do if the global economy remains dependent on fossil fuels for its energy needs. To put this in perspective, the carbon we put in the atmosphere today will literally determine not only our climate future but that of future generations as well.

A stronger greenhouse effect will warm the oceans and partially melt glaciers and other ice, increasing sea level. Ocean water also will expand if it warms, contributing further to sea level rise.

On Earth, human activities are changing the natural greenhouse

Water vapor. The most abundant greenhouse gas, but importantly, it acts as a feedback to the climate.