Every week, 300 glass air flasks from nearly 100 sites around the globe arrive at the National Oceanic and Atmospheric Administration (NOAA) office in Boulder, Colorado. The flasks – which measure slightly larger than a wine bottle, swaddled in blue and white fabric – contain samples of air composition from monitoring sites in places like Summit, Greenland; Ellesmere Island, Canada; and Barrow, Alaska. After technicians unpack each cardboard box, the flasks are rigged up to an array of whirring machinery that spouts off carbon dioxide and methane measurements, as well as those of 58 other species [indicators]. When they finish, they’ve essentially established the planet’s atmospheric record.

Pieter Tans has presided over the Carbon Cycle Greenhouse Gases Group for 32 years, bearing witness to the immense changes happening in our atmosphere. Last September, the Earth hit a major milestone – at a time when atmospheric CO2 is usually at its minimum, the monthly value failed to drop below 400 parts per million (ppm). Months earlier, Antarctica’s South Pole Observatory cleared 400ppm for the first time in 4 million years. And 2016 marked the fifth year in a row where global CO2 surged by 2ppm per more. Arctic Deeply recently caught up with Tans to discuss his career, the global acceleration in atmospheric CO2, and why monitoring Arctic air is so important.

Arctic Deeply: How did you first get involved with the Greenhouse Gas Reference Network?

Pieter Tans: I became aware of climate change, partially caused by CO2 emissions, in 1972. I was still in the Netherlands, as a student studying physics. I saw this book in a bookstore – “Man’s Impact on Climate” – and I thought, “What? That’s absurd.” So I took it off the shelf, and I saw the first 10 years of the Keeling Curve, showing every year CO2 was higher, and I thought, “Maybe there’s something to it.” I knew that these gases absorb infrared radiation, so really it was sort of a no-brainer. I bought the book, read it cover to cover and I changed careers then. I went from physics to geosciences. In 1978, I received a post-doc position with Charles David Keeling in San Diego. And then I came to NOAA in 1985 and I’ve stayed here since.

Arctic Deeply: And the network had started by then?

Tans: The program had already started – flask-measuring started in the mid-1970s. We had about 15 to 18 sites and were looking for more that might be good to place a continuous instrument. At that time, we just measured CO2 and had just started methane. Gradually, we added more and more species, and today we now measure 60 species at roughly 100 different sites around the world.

Arctic Deeply: Why do you want a variation of sites? How might what you’re getting from Arctic sites differ from a site like, say, Mauna Loa in Hawaii?

Tans: The Arctic is warming faster than other places on Earth and there’s a lot of speculation surrounding permafrost melt. To give you an idea of the magnitude, the current amount of CO2 in the atmosphere is about 800 billion metric tons (784 billion long tons) of carbon. Before the Industrial Revolution, it was more like 600 billion metric tons. We have burned slightly more than 400 billion metric tons of fossil fuels. The amount of carbon stores in the Arctic’s organic matter has been estimated to be as large as 1,500 billion metric tons. It’s many times everything we’ve burned so far. There is potential for huge positive climate feedback – where warming causes additional CO2 and methane to be emitted to the atmosphere. We want know, in our network, can we see something that indicates this is already happening on a large scale? We know that these things are happening in specific places, but we don’t know how much is being released in the entire Arctic. We can look at the air and compare, for example, concentrations of methane in the Arctic and compare them with mid-latitudes. If methane starts to be emitted in huge quantities in the Arctic, the Arctic measurements will be pumped up a little bit compared to the mid-latitudes. We look for that in our Arctic flasks. Eventually, these emissions will make their way to the South Pole, but it takes about a year. So far, the good news is we have not seen a measurable enhancement in the Arctic relative to the mid-latitudes.

Arctic Deeply: This is a huge global network, with sampling sites in several countries. How do you facilitate international collaboration?

Tans: International collaboration is a huge part of this. We have, for example, samples from Mongolia taken by a teacher. It’s a logistical challenge. You have to get them sent the flask on time. We get samples from the middle of the Pacific Ocean from a tourist operation – this person takes tourists fishing in a catamaran and they take two samples every week from the catamaran.

Arctic Deeply: Have you had sampling sites shut down due to geopolitical conflicts?

Tans: Four or five years ago, Kazakhstan was shut down due to geopolitical conflict. It had nothing to do with people getting tired of the United States – this might happen next. We’re making ourselves an outcast.

Arctic Deeply: Right. You’ve been in this area for 30 or so years. Do you have concerns for NOAA’s Global Monitoring Division under the new administration?

Tans: It’s best for me not to comment on that. But the truth is there.

This interview has been edited for brevity and clarity.

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