This afternoon, the Scripps Observatory daily CO2 reading at Mauna Loa was 401.62 ppm, this is the first daily reading above 400 ppm in 2014. Hourly readings topped 402 ppm.
The last month's readings track the increase which will continue likely into May or perhaps early June, 2014.
Through this week, readings have been creeping higher globally with the METOP-IASI global mean methane topping 398 ppm on March 11 2014 12-24 hrs UTC at 945 mb. The areas in yellow have readings above 410 ppm.