The sharp decline in biodiversity is the result of multiple human factors working together. Habitat destruction poses a direct threat, with 23 hectares of forests disappearing every minute globally, and the Amazon rainforest shrinking by 17% in the past 50 years, resulting in 10% of known species losing their living space. The process of urbanization also devours natural ecology. The wetland area in China has decreased by 53% compared to the 1950s, and 80% of lakes in the Yangtze River Basin have lost their fish migration channels. As a result, species such as the white dolphin have become functionally extinct. The expansion of agriculture has exacerbated this crisis, and after Southeast Asian oil palm plantations replaced primary forests, the local chimpanzee population has sharply decreased by 80%. Overexploitation exacerbates the situation, with approximately 27000 species globally endangered each year due to illegal trade, and populations of species such as pangolins declining by 94% within 20 years.

Environmental pollution generates cascading effects through the food chain. The abuse of pesticides has led to a sharp decline in the number of pollinating insects, and neonicotinoid insecticides have caused a 40% decrease in bee populations in Europe and America, directly affecting 76% of crop pollination. Plastic pollution has invaded remote ecosystems, with plastic fragments found in the stomachs of 90% of seabirds and a ratio of 1:2 between plankton and plastic particles in certain areas of the North Atlantic. Eutrophication of water bodies has led to the expansion of hypoxic death zones, and the 20000 square kilometer "dead zone" in the Gulf of Mexico has caused a large number of marine organisms to suffocate and die. Climate change disrupts the adaptation rhythm of species, with global warming increasing coral bleaching by 4% annually and potentially destroying 60% of coral ecosystems by 2030.

The invasion of alien species and the spread of diseases pose a special threat. About 7000 species of organisms are transferred across borders every day through ship ballast water and other means, and the invasion of cane toads in Australia has led to the extinction of 10 native reptile species. Human activities have accelerated the spread of pathogens, and pot mold disease has been transmitted through pet trade, causing the collapse of over 500 amphibian populations. These factors form a vicious cycle: when key species disappear, the entire ecosystem will collapse in a chain reaction, such as the decline of North American gray wolves leading to the flooding of deer herds, which in turn leads to the destruction of riverbank vegetation and soil erosion. The United Nations report shows that the current rate of species extinction is 1000 times higher than the natural background value, and about one million species may disappear in the next few decades.