On June 3, the
Scripps Institution of Oceanography and the National Oceanic and Atmospheric Administration (NOAA), which tracks global carbon emissions, made another dire announcement.
The American agency said that atmospheric carbon dioxide peaked in May at an average of more than 420 parts per million, “pushing the atmosphere further into territory not seen for millions of years.”
This measurement is often reflected in something called
the Keeling Curve, a graph that illustrates the changes in atmospheric carbon dioxide (CO2) over time.
The graph gets its name from Charles David Keeling, the American scientist who developed the accurate way of assessing atmospheric CO2. (He died in 2005.)
What the graph has steadily shown since its inception in 1958 is a rapid increase in atmospheric CO2 — and, as everyone knows by now, more CO2 means more global warming.
The Keeling Curve has been instrumental in measuring the rate of CO2 in the atmosphere, but that wasn’t always the case.
Around the turn of the 20th century, some scientists theorized about the
potential link between burning fossil fuels and increasing carbon dioxide, but it was still poorly understood.
Keeling developed his unique and incredibly precise instrument to measure CO2 in 1953, and in 1956, his invention caught the attention of a few scientists, including ones at the U.S. weather bureau and the Scripps Institution in California. A global CO2 monitoring program was proposed, with stations set up at Mauna Loa in Hawaii and the South Pole. Today, there are hundreds of these analyzers set up around the world.
So, how does it work?
First, scientists
collect air in a glass flask, which is taken to a lab and put through an infrared analyzer called a manometer. Using different wavelengths, scientists can determine how much CO2 is in the sample and even tell where it came from, be it an ocean, plant or vehicle.
The analyzer measures the amount of carbon dioxide molecules in a million parts of air. When the first reading was taken at Mauna Loa in March 1958, the measurement was 313 parts per million (ppm), meaning that in one million particles of air, there were 313 particles of carbon dioxide.
In the years after Keeling devised his measurement system, Scripps managed to gather more data on CO2 concentration by collecting ice cores from the Antarctic, which allowed it to extend the graph as far back as 800,000 years ago, to a time when CO2 was just 250 ppm.
The early use at Mauna Loa also revealed something quite interesting: CO2 concentration varied not only throughout the day, but also seasonally. In the spring and summer, the planet removed CO2 from the air for plant growth and returned it to the atmosphere in the winter. Essentially, it showed the planet breathing.
Since then, the Mauna Loa location has become the leading location for analyzing atmospheric CO2.
“The Mauna Loa record developed iconic status, because it was such a brilliantly precise and just overwhelmingly clear signal of human impact,” said Ralph Keeling, Charles David Keeling's son and a professor of geochemistry at Scripps.
Despite the many analyzers around the world, Ralph Keeling said the Mauna Loa location is still one of the best locations on the planet for these observations.
“It's on an island on a mountain in the middle of the ocean,” Keeling said. “It's like a probe sticking into this remote part of the atmosphere. So the air that it sees is really characteristic of a large chunk of the world.”
For all its technological innovation, what's most profound about the Keeling Curve is what it tells us. The upward trend in carbon concentration is undeniable. While it was 313 ppm in 1958, today it has soared to 420 ppm. Ralph Keeling said it’s likely we will reach 450 ppm within the next decade.
The consequences? More global warming. More severe weather, including droughts, heat waves and floods.
Canada has its analyzers, which have shown a steady rise as well.
According to Environment and Climate Change Canada (ECCC), from 1976 to 2020, the annual average CO2 concentration rose by 24 per cent, from 333.4 ppm to 415 ppm. ECCC notes that annual changes in CO2 are in line with the changes that have been observed globally.
Ray Nassar, a research scientist at ECCC whose area of research focuses on greenhouse gas measurements, said that while the Keeling Curve is important, so is being able to measure emissions closer to home.
“If we want to be able to address climate change, which I think most of us do want to do, then we have to understand what's going on with our own emissions,” Nasser said. “And people always say you can't manage what you can't measure.”
One of the key takeaways from the Keeling Curve is that the world isn't taking action fast enough, Ralph Keeling said.
“It's a bottom line on the collective effort to slow the problem,” he said. “And it shows that we haven't done anything near enough yet.”
—
Nicole Mortillaro
