Atmospheric Carbon Dioxide Update

Weekly average CO₂ at Mauna Loa Observatory 

• Week of April 21, 2013:     398.68 ppm
• Weekly value from 1 year ago:     396.66 ppm
• Weekly value from 10 years ago:     378.46 ppm

One Year of  CO_{2 d}aily and weekly means at Mauna Loa

The graph, updated weekly, shows as individual points daily mean CO₂ up to and including the week (Sunday through Saturday) previous to today. The daily means are based on hours during which CO₂ was likely representative of “background” conditions, defined as times when the measurement is representative of air at mid-altitudes over the Pacific Ocean. That air has had several days time or more to mix, smoothing out most of the CO₂ variability encountered elsewhere, making the measurements representative of CO₂ over hundreds of km or more. The selection process is designed to filter out any influence of nearby emissions, or removals, of CO₂ such as caused by the vegetation on the island of Hawaii, and likewise emissions from the volcanic crater of Mauna Loa.  Source: ESRL/NOAA

Recent Mauna Loa CO₂

• March 2013:     397.34 ppm
• March 2012:     394.45 ppm

Recent Global CO₂

• February 2013:     395.98 ppm
• February 2012:     393.05 ppm

Related Links

• 400 PPM  posted April 3, 2013