While the soldiers depicted in the poem are more threatened by the freezing wind than by bullets, it's worth noting that it is only because of the war that the soldiers are exposed to bitter nature without the normal protections of civilisation: shelter, heat, food, warm clothing, and so on. Owen uses nature to argue that the way war exposes the soldiers to the fury of winter emphasises the futility, meaninglessness, and dehumanizing brutality of the war. The men are given no chance of glory and instead are reduced to an animal-like state, forced to endure the wrath of nature that civilization was supposed to have tamed, and which they cannot survive.