Well, quite simply put, biochemistry is the study of chemical processes as they occur in living organisms. Exactly how would climate change affect living organisms? Let's say the climate decides to head into the next ice age, lowering temperatures across the board on a global basis. That would have an effect on living organisms metabolism, they would probably burn fuel faster in an attempt to adjust the body's internal thermostat. Think of all the chemistry that goes on in the digestion of one meal, to supply the body's cells with energy. How would the upcoming ice age affect the integumentary system, the skin, the hair, the nails? There is a whole cosmetics industry dedicated to preserving and beautifying the hair, nails, and skin right now; what new issues would be brought about as a result in the changes in physiology of the skin? There are about a gazillion different factors that go into analyzing the body's chemical attempts at survival. Understanding the controls that dictate what the body will do in a given situation help in making accurate predictions for the future.