Why does the extreme cold "make no expression" on the man?

The man has no idea what he's in for; therefore the cold makes no impression on him. He's inexperienced, he's over confidant in his abilities, and he refuses to listen to the advice of others who are experienced and who no better. The man believes himself to be on a timed trek, but he's not. He doesn't consider the true force of the cold, the weather, his supplies, problems that might occur; he just blindly moves on and thinks himself greater than the nature he practically dares to stop him. I wrote an article on this story from my experience with it in our school book club; you can find the link below;

I would add that the cold is simply indifferent to the man. London tends to personify the elements and in this case he is reminding us of not so much how unforgiving the cold is but rather how neutral the elements are concerning all living things, including the man.