THE SCIENCE BEHIND THE GREENHOUSE EFFECT & GLOBAL WARMING
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- Our own Horst Rademacher gave a fascinating overview of the science behind global warming which he categorized under three key factors (for a copy of Horst’s presentation, click here):
- A man: Dave Keeling
- An unusual data set: NOAA’s study of our atmosphere over time
- A molecule: CO2
In the middle of the 20th century very little was known about Earth’s atmosphere other than its major chemical components – i.e. 78% of the air we breathe is nitrogen, 21% is oxygen, .9% consists of noble gases (radon, xenon and the like), and the remainder trace gases such as nitrous oxide and ozone. Water vapor is also a component and is variable from region to region.
Starting in the 1950’s, Geochemist Charles David Keeling wanted to measure the exact amount of carbon dioxide in our atmosphere. He knew that such measurements would need to taken away from cities and forested areas – he needed a “neutral” location where air would be mixed by global air currents and offer an accurate representation of CO2 concentrations at any given time. Thus, in 1957, the NOAA weather station on Mauna Loa on the Big Island of Hawaii was chosen.
Over time, the data collected revealed something interesting an alarming. First, it was apparent that the amount of CO2 varies seasonally, with lower amounts appearing in the summer and higher amounts in .jpg)
winter (corresponding to the natural cycle of deciduous trees). As measurements were recorded over time – from 1960 to 2010, a sharp rise in atmospheric CO2 was confirmed. In fact, carbon dioxide emissions have spiked up 27% over the past 57 years. Similar measurements taken at other locations around the globe support this data. Average CO2 concentrations In our atmosphere equate to about 400 ppm – and rising. No natural causes have been linked to such a sharp increase. The burning of fossil fuels, however, has been shown to correspond to this dramatic rise.
Carbon dioxide is an odorless, colorless gas that is heavier than air. It can be deadly in high concentrations. The sun shines down upon the Earth and generates heat, which is reflected back into the atmosphere as infrared radiation. The CO2 in the atmosphere absorbs and stores this heat, causing the greenhouse effect. Greater quantities of CO2 in the air mean greater amounts of heat being trapped and creating a cycle of global warming.
Speculation is that the increased heat in our atmosphere will change global weather patterns, melt polar ice caps and change sea levels. Whether these changes will be irreversible is anyone’s guess and it is unknown how man-made increases in atmospheric carbon dioxide compare to natural fluxuations over time. One thing is clear, however, and that is that amount of CO2 in our air will continue to be a topic of social and political debate.