Featured by NOAA, a member of the U.S. Global Change Research Program
At NOAA's atmospheric baseline observatory in Barrow, Alaska, captured here by fisheye lens, the concentration of the greenhouse gas carbon dioxide reached 400 ppm in April 2012, the first time a monitoring sites reached the 400 mark. Carbon dioxide levels are steadily increasing in the atmosphere due to human activities, primarily the burning of fossil fuels. Image credit: NOAA
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.
â€œThe northern sites in our monitoring network tell us what is coming soon to the globe as a whole,â€ said Pieter Tans, an atmospheric scientist with NOAAâ€™s Earth System Research Laboratory (ESRL) in Boulder, Colo. â€œWe will likely see global average CO2 concentrations reach 400 ppm about 2016.â€ Read moreâ€¦