1. IntroductionBiodiversity, a word derived from biological diversity, is the variety of all forms of life: the different plants, animals and microorganisms, their genes and the communities and ecosystems of which they are part. Biodiversity is generally recognized at three levels: genetic diversity, species diversity and ecosystem diversity. Biodiversity loss is the local or global extinction of an allele or species. (Steffen, 2009) Australia is separated from other countries, so when biodiversity loss occurs in Australia, it could be more severe than in other countries. In this report, two causes of biodiversity loss are demonstrated: climate change and past and present human actions, as well as their effects and their comparison. Two causes2.1 Climate change2.1.1 EffectsThe evidence for the effects of climate change is verified by various researches. The first would be the rise in sea level (1.8 mm/year between 1960 and 1983 and 3.1 mm/year after this time) and tropical sea level due to climate change, which would lead to the loss of wetlands, low-lying islands and coastal areas. ecosystems. Climate change is also causing the global average temperature to increase by around 2°C, making it difficult for animals to adapt to these changes. As a result, many species will disappear. Additionally, many areas were very vulnerable, such as the Great Barrier Reef, Australian Alps, Wet Tropics of Queensland, Kakadu Wetland, etc. with changes in genetic composition, changes in migration patterns of some birds, altered life cycles of some species and reduction in the rate of reduction of others, etc. (Healey, 2001, p7, Steffen, W et al, 2009) 2.1.2 Compare To support the effects of climate change on Austarlia's biodiversity...... middle of article...... maxima lacials, peak cold, about 90 species disappeared. In addition, 50,000 years later, other species disappeared, but well before the arrival of the first aborigines. Thus, Malheur has a different conclusion as to the major cause of the extinction. ConclusionIn conclusion, climate change and human actions both impact Australia's biodiversity, but each has a different effect. While human actions are more likely to cause the extinction of animals in the past, such as those of giant animals 40,000 years ago, climate change today is causing loss of biodiversity, such as the loss of areas wetlands or low islands. Although controlling the impacts of climate change can be a challenge for the whole world, it is possible to reduce its impact by discovering the reason and solving these problems. .