Oops, it turns out I never published this post back in early June when I wrote it. I’m going to publish June’s data later today.
An average of 394.16ppm CO2 concentration was measured at Scripps’ Mauna Loa, Hawai’i’s Observatory during May 2011. Normally, I report on the NOAA observation, but it hasn’t been updated yet this month. When they do, I’ll update this post. The rest of this post will compare Scripps data against Scripps data – not Scripps versus NOAA.
That value is the highest in recorded history. Last year’s 393.22 was the previous highest May value ever recorded. This year’s value is 1.13ppm higher than May 2010.
The yearly maximum monthly value normally occurs during May. The 394.16 concentration is therefore likely to be the highest value reported this year.
This will likely be the last year that CO2 concentrations will fall below 390ppm during any calendar month. The aggressive march toward 400ppm continues. Keep in mind that scientists have recommended that 350ppm should be the target for which humanity should aim in order to keep climate extremes from overwhelming our civilization.