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Climate Change and Coral Reefs Quick Facts

What is Climate Change?

Both natural and anthropogenic (man-made) processes contribute to changes in global weather patterns such as temperature, rainfall, snowfall and wind. These changes have been observed throughout earth�s history, but with the onset of the industrial revolution and the human population explosion, increases in the intensity of climate changes associated with human activities have been reported with growing frequency.

Human activities such as the burning of fossil fuels, land use changes and agricultural industry practices, to name but a few, have altered the atmospheric concentrations of greenhouse gases. This shift inthe natural balance of atmospheric gases has led to an increase in the amount of heat that is trapped within the earth's atmosphere, producing a global warming effect. Carbon dioxide, methane and nitrous oxide are all examples of greenhouse gases - carbon dioxide being the most abundant of these in our atmosphere.

Bleached Coral
Photo: Lad Akins

What are the impacts of climate change and those specific to coral reefs?

Climate change is affecting people and the environment around the world. Signs that changes are occurring now include:

  • Higher air and ocean temperatures.
    Global surface temperatures have risen by 1.3 degrees Fahrenheit over the last 100 years 1 and the last ten years have been the warmest on record worldwide.2 Higher sea temperatures and light intensity have lead to more frequent mass bleaching events on coral reefs. Bleaching occurs when corals, and a number of other reef organisms, under the stress of overheating (or in response to other stressful conditions such as cold water, fresh water pulses or pollution), expel algae, called zooxanthellae, from their tissues.

    The relationship between coral polyps and zooxanthellae is important for coral growth and survival. Under normal conditions, the zooxanthellae provide nutrition to the coral. The zooxanthellae also provide the corals with their vibrant colors. Under conditions of increased stress, the coral-algal relationship is disrupted and the zooxanthellae either die in the coral tissue or are released from the tissue which causes the coral to lose its color. The bright white coral skeleton is then visible through the tissue, making the corals appear bleached. Bleached corals are still living and, if stressful conditions subside soon enough, zooxanthellae can repopulate their tissues and the corals can survive the bleaching event. 3

    Drought, forest fires, flooding, tropical storms and hurricanes are also increasing in frequency and intensity due to climate change. Higher air and ocean temperatures as a result of increased atmospheric greenhouse gases are producing a domino effect that is contributing to the following impacts.

  • Sea level rise.
    As sea temperatures increase, the warmer water expands (a process known as thermal expansion) leading to rising seas. Areas of low elevation, such as south Florida and islands are threatened by inundation, shoreline erosion and severe damage to both property and coastal ecosystems such as mangroves and wetlands that protect the shore from storms.

  • Melting arctic ice and glaciers.
    As a consequence of higher global temperatures there has been a marked increase in the rate of arctic ice and glacier melt compounding the effect of sea level rise and decreasing the area of available habitat for arctic wildlife.

  • Ocean acidification.
    Rising levels of atmospheric carbon dioxide also mean that the amount of carbon dioxide being absorbed by the oceans is increasing; and, as carbon dioxide levels go up, the pH of seawater goes down, making it more acidic. This chemical reaction reduces the number of carbonate ions in seawater available for corals and other marine organisms to build their calcium carbonate skeletons.

What is Florida doing?

Through the Florida Reef Resilience Program (FRRP), reef managers, scientists, conservation organizations and reef users across South Florida have developed a Climate Change Action Plan for the Florida Reef System (2010-2015). The goals of the Action Plan are to:

  • Increase coral reef resilience to climate change impacts through active management of local reef impacts.
  • Enhance communication and awareness of climate change impacts on coral reefs and reef users.
  • Conduct targeted research to increase understanding of climate change impacts and develop new intervention measures.

Click the link below to view the complete Climate Change Action Plan for the Florida Reef System (2010-2015) and learn about the specific recommendations identified to increase reef resilience to climate change and minimize impacts from threats such as land based pollution, and negative fishing, diving and other reef use. Actions can be taken today by reef managers and reef users to implement these key recommendations. Combined with state, national and international climate and energy policies, these actions can enhance the resilience of Florida's and help protect our state's vital resource.


1 www.epa.gov/climatechange/

2 Climate Change 2007: Synthesis Report � Summary for Policy Makers. Contribution of Working Groups I, II and III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change Core Writing Team, Pachauri, R.K. and Reisinger, A. (Eds.) IPCC, Geneva, Switzerland. pp 104

3 Marshall, Paul and Schuttenberg Heidi. A Reef Manager's Guide to Coral Bleaching. Great Barrier Reef Marine Park Authority, Townsville, Australia. 2006.

Last updated: April 06, 2015

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