Zee Media Bureau
New Delhi: Carbon dioxide (CO2) concentrations in the atmosphere have crossed the symbolic 400 parts per million (ppm) threshold at several stations of the World Meteorological Organization’s Global Atmosphere Watch network, the United Nations agency revealed on Tuesday.
Mauna Loa, which is the oldest continuous atmospheric measurement station in the world, recorded a reading of 400.03 ppm in the daily mean concentration of atmospheric carbon dioxide on May 9, 2013.
Earlier in April of this year, Izaña in Canary Islands, Spain, reported daily mean values exceeding 400 ppm.
These high presences of CO2 in the atmosphere were first registered in the Arctic stations during the seasonal maximum. Barrow in Alaska, USA, was the first station to record the monthly average value exceeding 400 ppm in April 2012. Other stations in the Arctic to cross the threshold were Alert, in Canada and Ny-Ålesund, Norway.
Carbon dioxide is mostly responsible for global warming effect over the last decade and is the single most important greenhouse gas emitted by human activities.
According to WMO, CO2 concentration has risen on average by 2 parts per million per year for the past decade and the global annual average CO2 concentration will cross the 400 ppm threshold in 2015 or 2016, at the current rate of increase.