Final answer:
The decline of the Great Barrier Reef's coral populations is primarily due to climate change-induced bleaching and oceanic acidification, combined with human-caused factors like pollution and overfishing. Together, these threats drastically reduce coral viability and pose economic risks.
Step-by-step explanation:
Impact of Climate Change on Coral Reefs
Scientists predict that by 2050, 95% of living coral in the Great Barrier Reef will have died due to the impacts of climate change and human activities. The increasing temperatures resulting from global warming cause corals to expel their symbiotic algae in a process known as bleaching. Without the algae, corals lose their vibrant colors and essential nutrients, leading to their death if the condition persists.
Additionally, rising levels of carbon dioxide in the atmosphere lead to oceanic acidification, further hindering corals' ability to calcify and form their exoskeletons. Human factors such as agricultural runoff, pollution, and overfishing also contribute to the deterioration of these critical ecosystems. The loss of coral reefs not only affects biodiversity and marine life but also poses a severe threat to coastal economies dependent on tourism.