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Climate change and tropical coastal ecosystems. Ove Hoegh-Guldberg Global Change Institute University of Queensland. Climate change. Ecosystems. People. Centre of Biodiversity Corals (>76%), mangroves (>70%) Seagrass (>70%), Reef fish species (37%)
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Climate change and tropical coastal ecosystems Ove Hoegh-Guldberg Global Change Institute University of Queensland
Climate change Ecosystems People
Centre of Biodiversity • Corals (>76%), mangroves (>70%) • Seagrass (>70%), Reef fish species (37%) • Epicentre of most marine organisms • 100 million people living coastally • Coastal resources are all important
Tropical coastal resources are critical to 100 million yet are severely threatened. • Coastal resources provide: • Food • Income • Building materials • Coastal protection • Wave energy • Storm/tsunami impacts • Coastal stability • Traditional medicines • Bio-discovery • Cultural importance Sea grass Local factors • Water quality • Over-fishing • Physical destruction Global factors • Ocean warming • Acidification • Sea level rise • Storm intensity Coral reefs Mangroves Loss so far: 30-50%. Coral reefs are declining at 1-2% per year (Bruno and Selig 2007)
The waters of the Coral Triangle are rapidly warming and acidifying ppm NOAA Up to 3-4oC per century (1-2oC is too much) ppm ppm Peñaflor et al., Coral Reefs in press; permission of Springer Science and Business Media Need blue conditions to maintain carbonate coral reefs
Tropical coastal resources are critical to 100 million yet are severely threatened. • Coastal resources provide: • Food • Income • Building materials • Coastal protection • Wave energy • Storm/tsunami impacts • Coastal stability • Traditional medicines • Bio-discovery • Cultural importance Sea grass Local factors • Water quality • Over-fishing • Physical destruction Global factors • Ocean warming • Acidification • Sea level rise • Storm intensity Coral reefs X Mangroves X Loss so far: 30-50%. Coral reefs are declining at 1-2% per year (Bruno and Selig 2007)
Implications for the future? Worst Case (IPCC A1B) Best Case (IPCC B1) 50% of current ecosystems by 2050 30% of current ecosystems by 2100 Food harvested (protein) 50% of today by 2050 30% of today by 2100 but rebounds Management of local threats makes big difference ... • 50% of current ecosystems by 2050 • <5% of current ecosystems by 2100 • Food harvested (protein) • 50% by 2050 • 5% by 2100, continues to erode • Management of local threats makes no real difference ... Extent of ecosystems relative to today (%) Atmospheric CO2 (ppm)
Conclusion: Not too late but we need to take 4 urgent steps: • Stabilise of atmospheric CO2 well below 450 ppm (and +2oC) • Reduce the impact of local stresses on coastal ecosystems • Decrease vulnerability of coastal people and infrastructure • Establish financial mechanism to allow CT countries to respond to inevitable changes