Carbon Dioxide Levels Reach Milestone at Arctic Sites
The concentration of carbon dioxide in the atmosphere of Barrow, Alaska, reached 400 parts per million (ppm) this spring, according to NOAA measurements, the first time a monthly average measurement for the greenhouse gas attained the 400 ppm mark in a remote location.
Carbon dioxide (CO2), emitted by fossil fuel combustion and other human activities, is the most significant greenhouse gas contributing to climate change.
The northern sites in our monitoring network tell us what is coming soon to the globe as a whole, said Pieter Tans, an atmospheric scientist with NOAA's Earth System Research Laboratory (ESRL) in Boulder, Colo. We will likely see global average CO2 concentrations reach 400 ppm about 2016. Read more