Global variables ( http://en.wikipedia.org/wiki/Global_variable ) are variables that are available throughout the entire program. This is defined by scoping ( http://en.wikipedia.org/wiki/Scope_(computer_science) ).
Beginning at 00401033 you see that two variables of size dword are being created and assigned their values.
These variables are then pushed onto the stack, and there is a call to a function. This just passed the variables into the function, so that they are accessible within the function's scope.
Inside the function, we see positive values for arg_0 and arg_4, meaning that these arguments are found up on the stack. This falls in line as the stack grows downward.