Yes, we’re at 400 ppm of carbon dioxide in the atmosphere, consistently now, everywhere. As a reminder, the pre-industrial number was something like 280.

For the first time since we began tracking carbon dioxide in the global atmosphere, the monthly global average concentration of this greenhouse gas surpassed 400 parts per million in March 2015,  according to NOAA’s latest results.

“It was only a matter of time that we would average 400 parts per million globally,” said Pieter Tans, lead scientist of NOAA’s Global Greenhouse Gas Reference Network. “We first reported 400 ppm when all of our Arctic sites reached that value in the spring of 2012. In 2013 the record at NOAA’s Mauna Loa Observatory first crossed the 400 ppm threshold. Reaching 400 parts per million as a global average is a significant milestone.

From a non-scientific sample of people I know, people who thought they were immune from seasonal allergies seem to be suffering them for the first time, and people who have always suffered them, which includes me, are reduced to slobbering insomniac messes. Could there possibly be a connection?