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March 23, 2017

Rising ocean temperatures threaten world’s coral reefs

  • Rising ocean temperatures resulting from climate change are killing coral reefs across the planet. Scientists say over 70 percent of the world’s coral reefs have been exposed to the high temperatures that cause bleaching.
  • The world’s largest coral reef is Australia’s Great Barrier Reef, which spans 1,400 miles and is the world’s largest living structure. For the second consecutive summer, warming waters have caused extensive coral bleaching there.
  • Many coral species have a symbiotic relationship with algae, which give them their vibrant colors and nourishes them through photosynthesis. When water temperatures rise even by a few degrees, algae produce a toxin that forces the coral to expel it. The coral becomes white and either recovers if temperatures lower or dies from lack of nutrients.
  • Coral reefs are home to the widest array of fish and plant species in the ocean, but pollution from sewage and agricultural runoff is already causing them stress. Scientists say the world needs to actively reduce its reliance on fossil fuels if it hopes to stop the threat of climate change and save them.
  • If nothing is done to reduce the impact of climate change on our oceans, “corals reefs as we know them will not exist in the next 10, 20, 30 years,” said Jennifer Smith, an associate professor in marine biology at the Scripps Institution of Oceanography at the University of California, San Diego. “We could single-handedly be responsible for the extinction of an entire ecosystem.”

Class discussion questions 
  1. Essential question: What are the impacts of climate change?
  2. Why is protecting coral reefs important?
  3. What do you know about the Paris Agreement?
  4. What do you think should be done to stop coral bleaching?
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