>roof are down tight, some keepers even cover them with plastic. Now, if the
>bees are using up the available oxygen, leaving carbon dioxide, which will
>rise with the heat created, the hive becomes a death trap.
 
   Here's where I believe you're wrong. All of the normal atmospheric
molecules (N2, CO2, O2, H2O, etc.) will be roughly evenly distributed
under normal circumstances, but if one (CO2) should increase in
concentration relative to the external hive atmosphere, it would tend
to diffuse out the bottom of the hive, regardless of the temperature.
Sufficient diffusion "pressure" should also be generated to allow oxygen to
diffuse in from the hive entrance (at the bottom of the hive). I believe
that the diffusion gradient forces will more than offset the temperature
gradient forces, thus you will never have a case of zero O2 in the air
circulating within the hive.
 
   Jeef