Methane joins CO2 in rising to historic levels

Mean Methane Levels reach 1800 ppb

Arctic News

On May 9, the daily mean concentration of carbon dioxide in the atmosphere of Mauna Loa, Hawaii, surpassed 400 parts per million (ppm) for the first time since measurements began in 1958. This is 120 ppm higher than pre-industrial peak levels. This unfortunate milestone was widely reported in the media.

Now another milestone has been reached that looks even more threatening than the above one. On the morning of June 16, 2013, methane levels reached an average mean of 1800 parts per billion (ppb). This is 1100 ppb higher than pre-industrial peak levels.

Vostok ice core analysis shows that temperatures and levels of carbon dioxide and methane have all moved within narrow bands while remaining in sync with each other over the past 400,000 years. Carbon dioxide moved within a band with lower and upper boundaries of respectively 200 and 280 ppm. Methane moved within lower and upper boundaries of respectively 400 and 800 ppb.

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