Dear Readers, as you might remember I am just about to start my BSc degree with the Open University, and I threatened to share with you some of the things that I’m learning. So here, for week one, is the Keeling Curve, the first study to show that CO2 was increasing in the world’s atmosphere over time, and considered to be one of the most important scientific works of the 20th Century.
Charles David Keeling, of the Scripps Institute for Oceanography at the University of San Diego was the first person to make systematic measurements of the amount of CO2 in the atmosphere, both from the Mauna Loa Observatory in Hawaii and from Antarctica. He started the readings in 1957 and continued until his death in 2005, when his son took over. The Mauna Loy site was chosen because it was remote from the pollution of the continents. Although the site is actually on a volcano, Keeling measured the onshore breezes and saw that they meant there was no contamination from the ‘vog’ (volcanic smog) that plagued sites further down the mountain.
Funding was always a problem for Keeling: for several years he wasn’t able to continue his monitoring in Antarctica, but he always scraped together enough to ensure that the Mauna Loa readings were done. As early as 1965, however, President Johnson’s Scientific Advisory Committee was using Keeling’s research to warn that the ‘trapping of gases’ was likely to cause the climate to warm up. As time has gone on, we are starting to appreciate the importance of ‘boring’ science – the taking of readings consistently over time to gradually build up a picture.
So, what do the readings show? In short, CO2 concentrations in the atmosphere have increased from 313 parts per million(ppm) in dry air in March 1958 to 406 ppm in November 2018. Scientists are in no doubt that this is largely due to the release of carbon back into the atmosphere via the burning of fossil fuels and deforestation, and I’m sure that I’ll have lots more to say about this as the course develops. Today, CO2 measurements are done at over 100 locations around the world, and their findings support the trend shown in the Keeling curve.
Interestingly, in the Northern Hemisphere there is an annual fluctuation in the CO2 levels. From a maximum in May, the level drops as plants put on new leaves and grow, taking CO2 out of the atmosphere. Then in October, as leaves fall and growth dies back, the CO2 levels climb again. You don’t see this effect in the Southern Hemisphere because there is a lot more ocean and a lot less land. However, we also need to bear in mind that in tropical zones plants don’t follow this cycle and only release their carbon when they die – also, they are normally very quickly broken down by all sorts of organisms, from bacteria to fungi, who tie the carbon back up again. The burning of tropical forests in the Amazon and South East Asia is hence particularly pernicious, as it is releasing massive amounts of carbon that might otherwise have been tied up for years.
The steady accumulation of scientific data by Keeling, in spite of facing many obstacles in getting funding, has been invaluable in alerting the scientific community to the rise in CO2 levels. This modest, self-effacing man was finally rewarded with the prestigious Medal For Science by President Bush, and received a special achievement award from Vice President Al Gore in 1997. But Keeling was a talented classical pianist, and one point early in his life wanted to pursue a career in music. I wonder who would have done this work if he hadn’t?Photo Credits
Photo One by By Delorme – Own work. Data from Dr. Pieter Tans, NOAA/ESRL and Dr. Ralph Keeling, Scripps Institution of Oceanography., CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=40636957
Photo Two by By National Oceanic and Atmospheric Administration – http://www.mlo.noaa.gov/aboutus/siteInformation/mlosite.html, Public Domain, https://commons.wikimedia.org/w/index.php?curid=7211086
Photo Three by By National Science Foundation –  , Public Domain, https://commons.wikimedia.org/w/index.php?curid=20025052