The story of climate change throws up a lot of numbers. Sometimes these numbers come alone. Sometimes they turn up with friends. Sometimes you get a whole load of them lined up together, plotted on a graph.
We're told we should feel something about these numbers, that they are significant. They're offered as cautionary tales, ghost stories, calls to action. They’re often bitterly fought over. But we're rarely told much about who made them.
So here's a story about numbers, a graph, and some people behind it.
Firstly, let me blurt out a load of numbers. 400, 350, 316.19, 405.71, 363.95, 380.25, 317.03, 324.14, 339.36, 371.33, 387.05.
They're readings from the Keeling curve, the graph of this story. 405.71 is the latest reading, from Sunday, 316.19 is from when this data was just starting to be collected, in March 1958.
They tell us how many parts of carbon there were for every million parts of the atmosphere at the point they were collected. Or to put it another way, for every million bits of the atmosphere you might catch today, around 405 bits of it will be carbon. It’s usually shorted to say parts per million, or simply ppm.
Four-hundred out of a million might not sound like much, but it only takes these kind of numbers to cause a fair bit of global warming.
400ppm is a slightly arbitrary point, but it made headlines in the last year or two as we hit it for the first time – first as a one off, then as the average for a whole month, then when we lived beyond it for a whole year. 350ppm is slightly less arbitrary. It’s a line in the ground deliberately drawn by climate scientist James Hansen when he declared it a safe upper limit. It’s where the NGO 350.org gets its name, a continual reminder that we’ve already past a point of safety.
It was already 363.95ppm the week the Kyoto Protocol was signed, and had grown to 380.25ppm by the time it had come into force, a bit under eight years later. It was 317.03ppm the week of JFK’s inauguration, 324.14ppm for Nixon’s, 339.36ppm for Regan, 371.33ppm W Bush, 387.05ppm Obama. You get the idea. You can download the data from the Scripps Institution of Oceanography if you want to look up your birthday.
Put all the data together - from 1958 to today - and you get the graph known as the Keeling Curve. It's called Keeling after the scientist who started collecting this data back in 1958, and it's known by it's curve because it's going up.
Graphs are little stories in themselves, and the Keeling Curve is a story of the gradual but alarming rise of CO2 deposited in our atmosphere. But this story isn't just interesting because it helps us keep track of how we’re changing our planet. The story of how the Keeling Curve came about and then kept on going says a lot about the growth (and precarity) of modern climate change research.
Charles David Keeling – Dave to his mates – grew up near Chicago. His dad was a financial analyst, his mother taught English. Dave was really into music, winning several piano competitions as a child, and continued to throughout his life. He studied chemistry first at the University of Illinois, before moving to do a PhD at Northwestern.
His PhD was on carbon, but more the end of things that’d be useful to plastic manufactures than anything to do with industrial emissions. What he really wanted though was a research project that’d let him out of the campus. He craved mountains, not the lab bench. In 1953, he moved to CalTech to work with their head of geochemistry. His work let him take carbon measurements outdoors, first checking whether rivers and ground waters were in equilibrium with the nearby air, and soon focusing just on the air alone.
This was not a topic that’d recommend itself to a young, ambitious scientist in the mid 1950s. Go chase the sexy biology the cool nuke guys we're defecting to, or see if you can score some bucks with rocket tech. But that was about to change, at least a bit.
Something called the International Geophysical Year was on the horizon, being planned for 1957-8. This is fascinating in its own right so I’ll do a whole post on it some time. For now, it’s enough to say there was a whole load of money floating around for the sorts of geochemistry Keeling did, and senior scientists were getting their knickers in a twist looking out for shiny new projects to spend it on.
By 1955, Keeling’s work had come to the attention of Harry Wexler, director of meteorological research at the US Weather Bureau, and Roger Revelle, the head of the Scripps Institution of Oceanography. The Weather Bureau was building an observation station at Mauna Loa in Hawaii, and Wexler was up for including a continuous programme of long-term measurement of CO2 there.
Surrounded by thousands of miles of clean ocean with a volcanic peak teetering high above the lower atmosphere, Mauna Loa is just a great place to study air. It was also a good place to test high-altitude equipment for the military, so the armed forces would be up for funding a road.
As has often been the case with climate change research (perhaps especially for the Keeling Curve) money was found because someone was interested in something else entirely.
Revelle, on the other hand, wanted to launch a network of sensors across the planet and use them to work out a baseline. It’d be a cool, global project for International Geophysical Year, then someone might apply for funding to repeat it in a decade or two and see if it had changed.
Keeling preferred the idea of long-term measurement, and trusted that a baseline could be collected at Mauna Loa. He’d been checking CO2 concentration in Pasadena and found it varied loads, probably because of local industry. He took his equipment out to Big Sur, a lightly populated stretch of California’s central coast. He found that though concentrations would undulate with plant growth between the start and end of the day, there was a remarkably consistent baseline in the afternoon, around 310 ppm. He repeated the experiments up and down the Pacific Coast, moving further afield to mountain tops, deserts and the sea, and got similar results.
Although Keeling liked the idea of a continuous programme with the Weather Bureau, he was more attracted to the working environment at Scripps. A sort of fudge of a double job was dreamt up – the then 28 year old Keeling would go to Scripps in the summer of 1956 to run Revelle’s global network of sensors, while Wexler’s Weather Bureau would also fund continuous CO2 measurement at Mauna Loa and in Antarctica. IGY paid for some snazzy new equipment and the military were up for helping on the Antarctic base.
Keeling put the Mauna Loa and Antarctica data together with what he had from all the ships and airplanes Revelle had him spinning round the planet. The results seemed to undulate with the seasons. The atmosphere sort of ‘breathed’ in carbon during the northern hemisphere's summer and let it out again in the winter. But beneath that was a consistent baseline. This breathing is what gives the Keeling Curve its distinctive zig-zag, along the upward trajectory.
Within a few years, he’d established that global concentrations of CO2 were rising in line with increasing fossil fuel consumption and land use change, and could credibly estimate that about half of the industrially emitted CO2 was staying in the atmosphere. Keeling had also proved the value of the continuous careful measurement from places like Manua Loa. The initial idea of running round the world to pick up a snapshot once every decade or so was falling by the wayside. Still, the future of the project was under threat.
The International Geophysical Year funding ran out by the end of 1958. At first, the US National Science Foundation (the NSF) filled the gap. But then Congress pruned the federal budget. They had to abandon the Antarctic monitoring, and Manua Loa suffered deep cuts.
In Spring 1964, a delicate instrument broke down and, missing a full-time technician, they had to shut. They just about bundled on after that, and 1965 brought with it some good news, with high level endorsement for CO2 monitoring from the President's Science Advisory Committee. But by 1970 there were threats of cuts again.
The international recognition Keeling’s work had received helped with things like NSF grants, and climate change was gradually climbing the global political agenda, but long term monitoring like this is never sexy. It doesn’t fit the patterns of most scientific funding applications, where you are asked to find something new, instead it just keeps tick-tocking away. Plus data this kind of data on how we’re messing up the planet isn’t the sort of evidence everyone wants to be reminded of. It’s immensely useful, but rather vulnerable to a politician's knife.
Keeling was possibly part of the problem too though, at least for some people. He was demanding, which arguably kept the research going, but it also put some funders off. As historian Spencer Weart puts it, “Some officials would have preferred to pursue CO2 monitoring without Keeling himself.”
There was some respite in the 70s when an Office of Carbon Dioxide Research was set up within the Department of Energy. This could be highly bureaucratic, but had money. Then, in 1981, Reagan was sworn in as president. For Secretary of Energy, he picked a trained dentist and former governor of South Carolina who wasn’t super keen on all this chat about global warming. Department of Energy climate research funding was, predictably, threatened with cuts. A young Al Gore – who had only joined Congress four years before – held a hearing that March, throwing some public spotlight on the threat to research. The cuts backed off, and the programme just about crawled through.
Keeling would continue to scratch together funds to keep the work going. He retired in 2003, but remained active in science until his unexpected death of a heart attack in 2005. Over the course of his professional life, he published over a hundred scientific papers, many coauthored with collaborators around the world. At a White House ceremony in July 1997, he was presented with a special achievement award from Al Gore who by then was Vice President. In 2002, he was awarded the National Medal of science by President George W Bush.
In an especially nice twist to a story of long-term, inter-generational data collection, Dave’s son Ralph Keeling now runs the Scripps CO2 program, adding fresh data to the Curve. The funding remains precarious though, and in 2013 they even had to launch a crowdfunding appeal.
In a way, the Keeling Curve remains a story without an end, as it keeps chugging out new information. An image of the Keeling Curve is carved into a wall at the National Academy of Sciences in Washington DC, but it’s still a very live piece of work, one that seems ill-fitted to a static monument. Or an essay such as this. If want to keep following the story, new readings are posted on Twitter.
Next up - drafting an obituary for coal.