2016 is likely to be the first year in recorded history in which levels of CO2 in the atmosphere remain above the symbolically important threshold of 400 parts per million.
BBC News - Home, BBC News
Mon, 10/24/2016 - 2:04am
2016 is likely to be the first year in recorded history in which levels of CO2 in the atmosphere remain above the symbolically important threshold of 400 parts per million.