Test analysis: dry test analysis, Engels emphasized that human activities have caused great damage to nature, which has caused human beings to suffer such damage. According to the analysis of each option, A, B and C are all contradictions in the world and have nothing to do with nature. Only the major changes in nature mentioned in item D will bring serious problems to human society, so the answer is D.

Comments: This question is not difficult. The key to solving the problem is to distinguish the contradiction between human society and the contradiction between man and nature. These are two different fields, which examine students' analytical and understanding abilities.