Using Figures 12a, 12b, 12c and your own knowledge, assess the scale of the threat facing this coral reef - AQA - A-Level Geography - Question 6 - 2020 - Paper 1

The Great Barrier Reef (GBR) is facing significant threats from multiple environmental factors.

1. Coral Bleaching: Figure 12a indicates areas most affected by coral bleaching in 2016, with substantial bleaching observed in the northern regions. This phenomenon occurs when corals expel the algae living in their tissues, which is essential for their survival, leading to the corals turning completely white and becoming vulnerable to mortality.

2. Acidification: According to Figure 12b, the estimated change in sea water pH due to human-created CO2 from the 1700s to the 1990s illustrates a trend towards more acidic waters. This process negatively affects coral growth and repair, making it harder for them to recover from bleaching events.

3. Temperature Anomalies: Figure 12c reveals the increasing trend of sea surface temperature anomalies from 1900 to 2016, with temperatures rising significantly post-1980. Increased temperatures can lead to more frequent and severe coral bleaching events, exacerbating the stress on coral ecosystems.

4. Additional Threats: Other factors impacting the GBR include pollution, overfishing, and coastal development, which collectively can disrupt local marine life and coral health.

In summary, the GBR is facing a multifaceted threat from environmental changes, primarily driven by human activities, which together threaten the long-term survival of coral ecosystems.