Naked Science Forum

Life Sciences => Plant Sciences, Zoology & Evolution => Topic started by: thedoc on 12/12/2016 20:53:01

Title: How do atmospheric gas concentrations vary with the Earth's seasons?
Post by: thedoc on 12/12/2016 20:53:01

Nuno Cruz asked the Naked Scientists:
   
Since, during winter, a lot of trees shed their leaves, is there a lower concentration of oxygen on the winter side of the globe? Does that also promote more carbon dioxide and in the end a warmer winter? So safer for the trees to survive?
What do you think?

Title: Re: How do atmospheric gas concentrations vary with the Earth's seasons?
Post by: chris on 12/12/2016 22:43:45

Gas concentration does vary with season, yes.

This is the graph for oxygen and carbon dioxide with time (from this paper https://ueaeprints.uea.ac.uk/33121/1/Manning_AC_et_al_GRL_2003.pdf):



Here's another graph for carbon dioxide (Image credit NOAA):


There are several reasons for this. One major mechanism is that, in winter, more fuels are burned to keep people warm in the northern hemisphere; this releases CO2 and draws down oxygen. At the same time, there is less photosynthesis because day length is shorter, temperatures are lower and trees drop their leaves. This means that there is less CO2 draw-down and less oxygen production.