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Prof. Ove Hoegh-Guldberg

Research > Climate Change

The rapid changes in the atmospheric concentration of carbon dioxide and other greenhouse gases are driving rapid changes in natural ecosystems across the full spectrum of environments. Arctic sea ice, for example, is disappearing so rapidly that it may well be absent from the Arctic by 2015. Similarly, the rapid melting of the great landlocked ice sheets of the western Antarctic and Greenland is set to drive up sea levels by a minimum of 1 m (and probably more) by 2100. Some continents are experiencing devastating droughts while others are experiencing dramatic changes to rainfall and are experiencing record floods.

Coral reefs have provided one of the most dramatic examples of how climate change can rapidly transform seemingly robust ecosystems. Corals, which are at the heart of coral reefs, are extremely sensitive to small changes in the environment. For example, sea temperature that are 1-2°C above the long-term summer temperatures will disrupt the symbiosis between corals and their symbiotic algae (zooxanthellae) resulting in bleaching (see separate research topic). Since the early 1980s, mass coral bleaching has resulted in the loss of large proportions of the world's coral colonies. Rising ocean acidity (driven by rising atmospheric carbon dioxide) has added to the problem of thermal stress, and is contributing to the serious decline in the acidification of corals and other reef builders.

Our research group has been involved in a wide range of climate change related research. This work is being mainly done on the Great Barrier Reef, at Heron and Lizard Island Research Stations. Recent work has focused on the synergistic interaction of elevated temperature and ocean acidification with the important discovery that the threshold for thermal stress is reduced if corals are exposed to acidified conditions at the same time. A research group is also planning an important study that will explore the effect of the ocean acidification on intact reefs in the field. This will be the first Free Ocean Carbon Enrichment (FOCE) on a living coral reef.

Topics

• Thermal stress
• Ocean Acidification
• Synergistic impacts
• Ecological ramifications
• Reef carbonate balances
• Projections of future change
• Adaptation options
• Assisted migration

Key questions

1. How does warming and acidification affect coral reefs, and how can we use this information to project how reef systems are likely to change in the future?

2. What are the impacts of losing reef calcifiers such as corals and calcareous algae on the three-dimensional complexity, biodiversity and ecological services provided by coral reefs today?

3. What are the consequences for coastal ecosystems and the people that depend on non-of the full range of IPCC scenarios?

4. Are there technologies and/or policies that can be used to reduce the impact of climate change on coral reefs?