Think about the air at the South Pole; imagine how clean and cold it would feel. The South Pole Observatory collects information from that air, specific carbon-dioxide readings from air samples collected in glass flasks. The observatory was established in 1957, the year when so much of the world’s Antarctic activity got underway as part of the International Geophysical Year; these carbon-dioxide readings from the geophysical pole date back to the 1970s.
That period – and 1972 in particular – holds a particular charge. 1972 saw the publication of the Stockholm Declaration, the result of the United Nations Conference on the Human Environment held in early June 1972. Principle 6 of that declaration insisted that
The discharge of toxic substances or of other substances and the release of heat, in such quantities or concentrations as to exceed the capacity of the environment to render them harmless, must be halted in order to ensure that serious or irreversible damage is not inflicted upon ecosystems.
This pulses with a very different energy fifty years later. In 1972, the carbon dioxide in the planet’s atmosphere – the primary greenhouse gas that causes global warming – was running at roughly 327 parts per million. Fifty years later, it’s breached 420 ppm, an increase of almost a third – and well over the planet’s safe operating limit of 350 ppm.
It almost feels like a cliché to offer up this particular story, to lay a single measurement of parts per million alongside another in order to underscore the speed of this change. But it’s critical to keep those numbers in mind, to contemplate the scale of difference across a short half century.