Atmospheric carbon dioxide level reaches historic high of 400 parts per million

The concentration of carbon dioxide (CO2) gas in the in the Earth’s atmosphere passed 400ppm (parts per million) according to the Mauna Loa Observatory in Hawaii in the Pacific Ocean, where researchers have been recording levels of CO2 in the atmosphere since 1957. Climate scientists are worried that increasing levels of CO2 will cause average global temperatures to rise which will have a significant impact on the planet’s climate system.