Why does the keeling curve go up and down

After a few years, Keeling observed a steady increase in atmospheric CO 2 , an indication that fossil-fuel emissions were building up in the atmosphere. Due to funding cuts, Keeling had to stop measurements at the South Pole, but the weather station in Hawaii continues to measure concentrations of CO 2. The data from these measurements are plotted on a graph known as the Keeling Curve. Keeling's findings were so profound that they prompted the National Oceanic and Atmospheric Administration NOAA to start monitoring CO 2 concentrations in other locations around the world.

All of this data indicates that CO 2 is building up in Earth's atmosphere. This video explainer is part of our Clue into Climate collection of resources. An interactive version of this explainer is featured in our Clue into Climate e-book series. Click on the tabs below to download our free e-books or subscribe to our iTunes U course.

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Thus over the course of the winter, there is a steady increase in CO 2 in the atmosphere. In the spring, leaves return to the trees and photosynthesis increases dramatically, drawing down the CO 2 in the atmosphere.

This shift between the fall and winter months to the spring and summer results in the sawtooth pattern of the Keeling Curve measurement of atmospheric CO 2 such that every year there is a decline in CO 2 during months of terrestrial plant photosynthesis and an increase in CO 2 in months without large amounts of photosynthesis and with significant decomposition.

May is the turning point between all the decomposition throughout the winter months and the burst of photosynthesis that occurs with the return of leaves to the trees in spring. CO 2 measurements all over the globe reflect this pattern of peak CO 2 concentration occurring each May, regardless of the level of that peak. To put this rapidly increasing number into perspective, consider that ice-core research shows that pre-industrial levels of carbon dioxide held steady around ppm from about AD.

The Keeling Curve. Like this: Like Loading Loading Comments