Robinson Meyer writes a weekly climate newsletter for The Atlantic called Not Doomed Yet. He leads off every edition with the same number: the latest data on parts per million of carbon dioxide (CO2) in the atmosphere.
“Even though I do it every week, I'm always surprised ... the atmosphere's changed a lot just in the last decade,” Meyer said.
That parts per million stat is an indicator of how much greenhouse gas is going into the atmosphere, and it's been steadily increasing since Charles David Keeling started measuring it in the 1950s.
Last month Bloomberg News provided a different look at that number with the Bloomberg Carbon Clock. Part data visualization, part public art project, it's a climate science cousin to the National Debt Clock: a ticking display that estimates the amount of carbon dioxide in the atmosphere in real time (there's some precedent for the idea: in 2009, Deutsche Bank put up a billboard near Madison Square Garden with a display counting tons of greenhouse gas).
To estimate carbon dioxide levels continuously, the clock combines weekly data from the Mauna Loa Observatory with historical trends (you can read the full methodology here). Because the model incorporates seasonal variation, it means the clock will actually stop and switch direction for a few months in the spring, when Northern Hemisphere vegetation removes more carbon from the air.
At the time of this writing (the exact millisecond, even), the clock is at 403.17908832 parts per million and counting. That's an increase from about 380 parts per million just 10 years ago.
One common target for stabilizing the climate is keeping that number under 450 parts per million. Eric Roston, one of the Carbon Clock's co-creators, refers to anything higher than that as the “danger zone.“ And he thinks focusing in on one key number helps cut through the complexity of climate data.
“It's the actual number that has driven a lot of science and policy for 60 years ... it'll be relevant for at least another 60 years, and it's a backdrop to what's going on every day,” said Roston.
Other recent climate visualizations include:
- The New York Times' chart putting the Paris agreement pledges in context
- The Financial Times' interactive simulator of possible emissions cuts by country
- Bloomberg's visualization of the influence of different factors on global temperature