Carbon dioxide levels in atmosphere forecast to shatter milestone

Scientists warn that global warming target will be overshot within two decades, as annual concentrations of CO2 set to pass 400 parts per millionAtmospheric concentrations of CO2 will shatter the symbolic barrier of 400 parts per million (ppm) this year and will not fall below it our in our lifetimes, according to a new Met Office study.Carbon dioxide measurements at the Mauna Loa observatory in Hawaii are forecast to soar by a record 3.1ppm this year – up from an annual average of 2.1ppm