In Guns, Germs, and Steel by Jared Diamond (Prologue, Chapters 1-6), who, for Diamond, has a bigger impact on the broad pattern of history: human actors or the natural environment in which human actors have lived?
The answer to this question is based on the most fundamental assertion that Diamond is making in Guns, Germs, and Steel. The main point of this entire book is that human actors have very little impact on the “broad pattern of history” because those broad patterns are dictated by the natural environment in which the people live.
When Diamond talks about broad patterns of history, he is talking about very broad patterns. The fact that the US has dominated the post-WWII world is not a broad pattern of history even though it seems like a very general fact to us today. The broad pattern of history that Diamond is talking about is the fact that Europe (and the descendants of Europeans) came to dominate the world beginning about 500 years ago.
In this book, Diamond is trying to determine why it is that Europeans and their descendants came to be so dominant. He explicitly rejects the idea that European people are somehow better than other groups of people. Instead, he says, it was geography that allowed the Europeans to dominate. The Europeans dominated because there were areas on the Eurasian landmass that had large numbers of domesticable plants and animals and because Eurasian geography made it relatively easy for those plants and animals to diffuse across the landmass. Because of these two factors, Europeans were able to get agriculture earlier than people in other parts of the world. By having agriculture, they became “civilized” and were able to acquire the “guns, germs, and steel” that allowed them to dominate.
The answer, then, is that in Diamond’s view the natural environment is much more important for the broad patterns of history, than the actions of the individual human beings who lived in the environment.