What is the impact of the Battle of the Somme on world history?
The historical impact of a battle such as this is hard to determine with any precision. We cannot know for sure how such an event impacts history.
One way to look at this, however, is to say that the horrors of the Battle of the Somme led to the desire to ensure that such a battle would never happen again if at all possible. The experience of this battle helped lead to the development of new ways of making war. It became clear that trench warfare was far too deadly and that something had to be done to avoid it. This led to the development of tanks in particular and of new doctrines that emphasized the importance of mobility in war.
The Battle of the Somme, then, served as something of an example of what notto do. It inspired military men to find other ways to fight. It did not end war, but it helped to push people to find new ways of fighting that would be at least somewhat less horrific.