I am preparing my AOSS class next semester, and I found it is interesting that there is a seasonal cycle of CO2. I looked for some information on the Internet, and this seems to do with the plants. They awake in the spring and summer, absorbing a lot of CO2 by photosynthesis and die in the autumn and winter, releasing the CO2 by respiration. But they seem to all mention that it is " in the north hemisphere ". So what happens in the south hemisphere? Is it because north hemisphere actually contains the majority of the landmasses which make the seasonal cycle phenomenon obvious?