Scientific instruments have a habit of presenting us with uncomfortable truths. Galileo’s telescopes showed that our solar system did not conform to the prevailing teachings of the day. The great particle accelerators show a complexity underlying reality that defies a simple explanation of the universe. Likewise an almost forgotten instrument sitting atop a volcano has shown that humans have altered our world in very damaging ways.
I had driven to the top of Mauna Loa for a session of Geminid meteor watching and photography, joining Steve, a local photographer and friend for a cold, beautiful morning atop the mountain. As we were about to leave another friend drove past. Ben used to work with me at Keck and now tends the solar observatory adjacent to the NOAA climate laboratory. Looking at the sky and the drizzling fog that had rolled in with the dawn he noted that it would be a while before he could open the telescope. Instead he offered us a tour.
It was in the main building that we stopped to look at a little instrument parked rather oddly in the hall. Not much, a simple box with a few aluminum tubes and a bit of circuitry and wiring. It took me a moment to realize I was looking at a piece of scientific history. Here was the Scripps Carbon Dioxide Analyzer that has provided the data that has changed our relationship with our planet.
This little instrument is an infrared carbon dioxide analyzer that was built by Applied Physics Co. and installed by Charles Keeling. Here, atop a volcano in the middle of the Pacific it was possible to get an unprecedented, clean sample of our planet’s atmosphere. For decades this instrument operated, telling a story of change. Measuring the result of a civilization powered by carbon based fuels, oil and coal, and what that has done to the atmosphere.
During my first good look into the guts of the instrument, my gaze was drawn to the circuit boards at the top. I immediately noted the age of the machine based on the components. Paper and foil capacitors, carbon composition resistors, all mounted to a pegboard style circuit board. And tubes! The active parts of this signal board is designed around tube amplifiers. I was looking at 1960’s era technology. A few moments later I read the little information display posted above, this instrument entered service in 1958. I looked again at the old circuits with an electrical engineer’s respect for those who designed this machine.
The carbon dioxide analyzer is no longer in service, it was retired in favor of more accurate instruments in 2006 after 48 years in service. An incredible run for a scientific instrument of this type. The analyzer sits as sort of a museum piece along the main hallway of the lab, unknown to any but those few who visit the remote site atop Mauna Loa. Someone has put some small labels on the parts, otherwise this historic instrument sits almost forgotten.
Two sample chambers are used, one with a reference mix of known gas, the other with a sample of the atmosphere drawn down a tube from a tower above the lab. By measuring the response of both tubes and comparing the ratio one can see the concentration of carbon dioxide in the air. The readout is a paper chart recorder, typical technology for 1958. Each day someone would have to take the chart and painstakingly transcribe the numbers into the records, in later years enter the data into a computer for analysis.
It is this data that has made this gas analyzer one of the most controversial instruments in the history of science. The Keeling Curve, that now famous and ever rising chart of atmospheric carbon dioxide was first plotted using numbers from this same gas analyzer. Now corroborated by data from many other sources the curve is impossible to dispute, the numbers are rising at an alarming rate.
Plot atmospheric carbon dioxide concentration alongside global temperature and the story becomes more concerning. Combined with what we know about the greenhouse effect, about the absorption of infrared light by carbon dioxide, we realize there is more energy coming from sunlight absorbed by the planet than before. The Earth is warming, and our carbon dioxide emissions are the cause. Oddly, it is the absorption of infrared light by carbon dioxide gas that is the principle by which the Mauna Loa gas analyzer works.
There’s still no explanation and no one can tell me yet what percentage of so-called climate change is due to human activity, what percentage is due to natural trends, natural cycles – Lamar Smith, chairman of the House Committee on Science, Space and Technology
The numbers are inarguable, but many still insist on doing so. The data is fabricated, or misinterpreted insist all too many. For many reasons people will not accept the findings of our climate scientists. For many it is simply that accepting the science would mean admitting that the technology that makes our lives so comfortable has come at a price. That fixing the problem may involve accepting uncomfortable changes to our lives.
It is not just one data set that tells the story. While Keeling’s gas analyzer atop Mauna Loa started our change in understanding, it is just part of the story, the first chapter. It was the data that alerted us to something that me might want to pay closer attention to. Slowly the attention of an entire scientific community was drawn to studying the problem. The findings have been confirmed dozens upon dozens of times. The effects of climate change have become visible all over our world. Maybe we can do something about it?