Final answer:
The passage primarily discusses how climate change impacts biodiversity and underlines its significance throughout human history.
Step-by-step explanation:
The central idea of the provided passage is most closely reflected by option B, which states that the passage discusses the impact of climate change on biodiversity. The passage outlines how climate change has historically shaped human history, affected biodiversity, and presents a significant threat to ecological variety and balance. Detailed examples such as historical climatology, the study of climate's effect on the fourteenth century, and contemporary concerns like habitat loss and the predicted effects of climate change on biodiversity, all demonstrate the critical relationship between climate change and biodiversity.