I believe everyone has the right to their own personal beliefs, however I don’t believe reputable magazines should print beliefs that have no scientific backing, especially a magazine for engineers. I’m referring to Hendrik Borgdoff’s letter, “Beyond our control” (September/October 2017). Back in 1824, the mathematician Joseph Fourier, whom engineers should have come across in their studies, calculated that the Earth’s average temperature, from the energy received from the sun, should be about -18 C instead of +15 C. He attributed this to our atmosphere holding in the heat. In 1896, Svante Arrhenius, a Nobel-Prize-winning chemist, put the blame on carbon dioxide. Scientists have been peer reviewing this ever since, and it is now considered a fact. We now know that CO2 is responsible for about 80 per cent of all non-condensing greenhouse gasses that are warming the planet.
PhD or not, I also take issue with Tapan Das’ letter where he states CO2 is now increasing at 2 ppm/yr (“Innovative solutions,” September/October 2017). I expect a PhD to be better at research. According to NOAA, CO2 has increased as follows: 2016 404.39, 2015 401.31, 2014 399.04, or in other words CO2 increased 3.08 ppm in the last full year of data. Scientists are still debating the rate of sea level rise. The IPCC seems to be Das’ source and is the most conservative of the models. The majority of scientists are in the range of up to a two metre rise by 2100, although James Hansen, using the increasing rate of ice loss from GRACE satellite data and extrapolating, shows it could be as high as five metres. A six-foot increase (USA data) shows that two-thirds of the world’s population would have to relocate away from the oceans. Over half our major cities would have to be relocated. The year 2100 is an odd date for considering sea level rise, as what we have done to date will result in the seas continuing to rise for thousands of years. Three million years ago, in the mid-Pliocene, when CO2 levels were similar to ours, sea levels were about 20 to 25 metres higher than today. In the past, it took about 10,000 years to come out of an ice age to a peak warmer climate. In the past, CO2 increased at about an average of 1 ppm per 100 years (Dome C ice cores). We are now increasing 300 times faster than that, and that is why we really don’t know how quickly the Earth’s systems respond. To date, it’s been faster than our predictions.
As engineers, it’s interesting to look at what it would take to design a machine to remove CO2 from the air. 400 ppm is equal to one part in 2500 volumes. In other words, using a machine that is 100 per cent efficient, this machine would have to run 2500 volumes of air through it for every volume it extracted. Then we would have to do something with the extracted CO2.
Lee Norton, P.Eng., St. Catharines, ON