Q:

Most effective environment for coboglobin

So after reading over other blood colors and the benefits of other blood bases I wanted to create a species that used Coboglobin instead of Hemoglobin. Though based off of Jim2B presented of,

On this chart it shows that Coboglobin is most effective at 15 Celsius body temperature and a lower partial pressure than Hemoglobin, (Still not sure what that means yet, but meh.)
With that information my question is what kind of environment would produce the most effective use of having such a low internal body temperature and lower partial pressure. (Assuming that it would be a warm bloodied creature.)

A:

For low pressure and cold a fictional biotic Mars would be a good choice. Even with an oxygen atmosphere it would have lower pressure and be colder. On earth tundra plateau would be good. 
But really almost any oxygen environment will work, it depends more on the animal you build around it. There are several different oxygen carrier in the same environment on earth becasue they all work good enough. The other anatomy of the organism has WAY more impact than the oxygen carrier. Things like circulatory system, hox genes, support structures are far more important. 

