In the unfolding story of global climate change, carbon dioxide (CO2) is the greenhouse gas that attracts the most attention. Its increasing concentration in the atmosphere, since the dawn of the Industrial Revolution nearly 250 years ago, is a significant factor influencing Earth's radiation balance and our global climate.
Beginning in 1957, the International Geophysical Year (IGY), researchers have been measuring atmospheric carbon dioxide levels at research stations around the world. Click here to view a graph of the data from Mauna Loa, Hawaii, also known as the Keeling Curve. What trend in atmospheric carbon dioxide concentration do you observe? How much has atmospheric carbon dioxide increased since you were born?
Question: Yearly fluctuations in atmospheric carbon dioxide concentrations can be observed in the Mauna Loa data. Look below to see a video clip showing the change in atmospheric carbon dioxide concentrations over a one and a half year period.
What do you think could be causing this seasonal variation to occur?
Hint: Consider how vegetation interacts with carbon dioxide, keeping in mind that the majority of the world's land mass is in the northern hemisphere.