Why you should take hyperventilating headlines about CO2 with a grain of salt — but still be quite concerned

This graph shows carbon dioxide concentrations in the atmosphere as measured at the Mauna Loa Observatory in Hawaii. The last four complete years of the record plus the current year are shown. The dashed red line red line shows monthly mean values, and reveals a natural, up-and-down season cycle. The black line shows the trend after correcting for the average seasonal cycle. (Source: NOAA Earth System Research Laboratory) Back in late April, there was a spate of hyperventilating headlines and news reports about the increasing levels of carbon dioxide in the atmosphere. This one in particular, from Think Progress, should have made its author so light-headed that she passed out: