How does the buildup of carbon dioxide in the atmosphere measured at Hawai‘i’s Mauna Loa volcano over the last six decades compare with the air above Alaska? During a recent spring trip to Utqiaġvik, I had a chance to find out by visiting the farthest-north atmospheric observatory operated by the National Oceanic and Atmospheric Administration (NOAA). It gave me a new appreciation about the global nature of climate change.
Because the Arctic is warming twice as fast as most places on Earth, a lot of recent climate research has been conducted at research facilities near Utqiaġvik, Alaska’s community “at the top of the world,” formerly known as Barrow. At NOAA’s Barrow Atmospheric Baseline Observatory, the story of the role greenhouse gases play in global climate change began unfolding earlier, in the 1970s.
When I toured the observatory in March, I was seeking local scientific data that might be used by middle and high school teachers to engage their students in understanding climate change, and in efforts to solve climate-related community issues. As the marine education specialist for Alaska Sea Grant, I teach courses for academic credit through the University of Alaska Fairbanks for teachers through a combination of on-site classes at schools and distance delivery. What brought me to Utqiaġvik was a course I co-teach for North Slope Borough School District teachers, called “Navigating a Changing Arctic Environment through Place-Based STEM Education.”
Bryan Thomas, the NOAA scientist who manages the observatory, began the tour by demonstrating the instruments he uses to sample carbon dioxide in the atmosphere daily.
Carbon dioxide (CO2) is a heat-trapping greenhouse gas, and too much CO2 in the atmosphere from fossil-fuel burning is a key driver of climate change. CO2 is one focus of the station’s climate research, but the collected air is also analyzed for other climate change drivers, including concentrations of ozone and methane, other greenhouse gases, and black carbon (soot) from the incomplete combustion of fossil fuels. Black carbon affects how much heat energy from the sun is reflected back into the atmosphere.
Thomas pointed to a poster in the station’s arctic entryway that showed the “Keeling curve” of CO2 concentrations in the atmosphere measured over several decades at the Barrow observatory and three others at Mauna Loa, American Samoa and the South Pole. Scientist Charles Keeling began taking measurements of CO2 at Mauna Loa in 1958, and the plotting of those measurements eventually became a “hockey stick” graph of rising CO2 levels.
Data collection at the Barrow station began in 1973, and the measurements at all four stations show the same precipitous upward trend. Thomas pointed out seasonal differences in the Barrow station measurement, with larger ups and downs than the other stations—up to 6 ppm (parts per million) difference. He explained that in contrast to the island stations and the South Pole, the Barrow station is surrounded by a large land mass with plants that suck up CO2 during the summer, resulting in larger “downs.” During winter, the Arctic Ocean and the surrounding lands are frozen, resulting in higher “ups” in comparison to stations at lower latitudes.
At the end of my visit, Thomas handed me a vial to collect my own air sample as a souvenir. I twisted off the lid and held it away from my body while holding my breath to avoid adding my own breath to the mix of air that filled the bottle. I quickly replaced the airtight lid. Thomas wrote the date and his own preliminary measurement of the CO2 levels for the day, one that would be refined later, he said, by a more sophisticated analysis.
During my visit, I learned that the air collected at the observatory is well-mixed by northerly winds blowing across the Arctic Ocean, and is among the least-polluted air on Earth. I therefore somehow expected the air to be “cleaner” with respect to greenhouse gases. But the thing about global warming is that the rise in CO2 driving climate change is truly, well, global. When Keeling began measuring CO2 in 1958, the concentration was 312 parts per million (ppm, just a little higher than the pre-industrial level of 280 ppm. In 1979, the first measurements at the Barrow observatory were already at 336.9 ppm. It’s noteworthy that 350 ppm correlates with 1°C change in the global temperature. Climate scientists have predicted that 400 ppm, correlated with 2°C change, will destabilize the climate in the form of severe weather events including extremes in temperature and precipitation. In Alaska, this will lead to coastal erosion, flooding, deeper thawing of permafrost, sea ice loss, changes in the distribution of fish and marine mammals, impacts to infrastructure, and other changes affecting food security, culture, economy and community wellbeing.
When I read the level of CO2 in my own sample on March 5, 2019, it was a startling wake up call. The handwritten data on my vial showed 397.99 ppm.
-written by Marilyn Sigman, Alaska Sea Grant marine education specialist