400 PPM: A Bad Sort of World Record

This month we set a new world’s record. By “we”, I mean the world. The world set a new record and this is not the sort of accomplishment we should be proud of.

On May 9, 2013, the carbon dioxide level in the atmosphere exceeded 400 parts per million.

The NOAA has been recording CO2 levels at the Mauna Loa Observatory since 1956 and two things are clear: a natural annual variation of 5-10 PPM, and a steady increase from year to year.

By studying ancient air bubbles trapped in ice cores, scientists are able to determine CO2 levels much further back, and we can see how exception this period since the beginning of the industrial era has been.

In fact, according to researchers at the Scripps Institution of Oceanography, the last time the Earth had so much CO2 in the atmosphere was during the Pliocene era over three million years ago.

Recent estimates suggest CO2 levels reached as much as 415 parts per million (ppm) during the Pliocene. With that came global average temperatures that eventually reached 3-4°C (5.4-7.2°F) higher than today’s and as much as 10°C (18°F) warmer at the poles. Sea level ranged between 5 and 40 meters (16-131 feet) higher than today.

Of course, at the record breaking clip with which we are releasing carbon into the atmosphere breaking the 415 PPM mark will be no challenge indeed. According to the International Energy Agency, we will reach 650 PPM even if we stop burning coal and replace it with natural gas.

It is therefore appropriate that Ira Glass chose this week to devote his show This America Life to climate change.

Episode 495 (May 17, 2013):
Hot In My Backyard

After years of being stuck, the national conversation on climate change finally started to shift — just a little — last year, the hottest year on record in the U.S., with Hurricane Sandy flooding the New York subway, drought devastating Midwest farms, and California and Colorado on fire. Lots of people were wondering if global warming had finally arrived, here at home. This week, stories about this new reality.