For centuries the carbon dioxide level has ben under 300 parts per million, now it's at 400 parts per million.

Earth-orbiting satellites have helped scientists collect different types of information about our planets global climate. This data, collected over many years, reveals the signals of a changing climate.

Carbon dioxide and other gases were dmostrated to trap heat in the mid-19th century, so the CO2 amount rising is making the greenhouse effect stonger.