Annotation category:
Chapter 3
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We show in the table below the record for the carbon dioxide concentration in the Earth's atmosphere as measured each month since January of 1958 at an observing station on Mauna Loa in Hawaii.
The dense table of numbers makes it extremely difficult to extract any meaningful trends, but time series plots (second and third images below) immediately reveal two striking patterns in the data: annual wiggles with a generally consistent amplitude of five to seven parts per million, and a rapidly rising average value which indicates a net increase of 60 parts per million or 19% in the past 45 years.
Furthermore, laying a straightedge over the midpoints of the annual cycles shows that the slope of the increase is getting greater with time. The yearly wiggles arise from the extraction of CO_2 from the atmosphere by plant growth in the summer months (see the plot of the monthly data for the last five years in which the minimum is reached at the end of the growing season in September/October), and its reintroduction to the atmosphere as decaying vegetation releases CO_2 in late spring. The long-term trend is a consequence of our burning of fossil fuels which is releasing CO_2, sequestered over 150 million years during of the age of the dinosaurs, in a few centuries. The accelerating increase is a consequence of our ever-rising demand for energy.
| Images: |
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Mauna Loa CO2 Data: Table |
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Mauna Loa CO2 Data: Full Time Series |
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Mauna Loa CO2 Data: 5-Year Time Series |