The most important of this gases in the natural greenhouse effect is water vapour, but concentrations of that are changing little and it plays almost no role in modern human - induced greenhouse warming, Other greenhouse gases include carbon dioxide, methane and nitrous oxide, which are thrown into the atmosphere by modern industry and agriculture. Their concentration in the atmosphere is going up - the concentration of carbon dioxide has risen by more than 30% since 1800. The majority of climate scientists accept the theory that an inscrease in these gases will cause a rise in the Earth's temperature, and say that human activites are to blame.