Coral Bleaching: Talking about Climate Change & Sustainable Solutions

Essential Question: How can we protect coral reefs from harm?

Duration: 10-20 minutes

Age Level: We designed this activity as a component of a longer classroom program for 3rd graders, but it can be tailored for conversations with older students, and even adults!

Why Do We Care?

Thriving coral reefs provide billions of people with food, protect our coastlines from storms, provide habitat for one quarter of all life in our oceans, and they are a vibrant place to explore!

We have a responsibility to protect these wonderful habitats from harm and it turns out they need help now!

Impact Story:

When we burn fossil fuels such as coal, oil and natural gas, we release carbon dioxide into the atmosphere. Unfortunately, this carbon dioxide acts like a thickening of a heat-trapping blanket that encircles our earth. As we burn more fossil fuels, we release more carbon dioxide and that heat-trapping blanket gets even thicker, our planet gets warmer, and so do our ocean waters.

In normal times, coral has a relationship with tiny colorful algae that lives in its tissues. The coral provides a home, and the algae (zooxanthellae) makes food which it shares with the coral.

Warming ocean water stresses the coral and stresses the special relationship that coral has with its algae. When oceans warm, coral expels the zooxanthellae from its tissues.Look at the colorful coral pieces in your model ocean. What do you think will happen to this colorful coral if the water gets warm? This is just a model – we would never harm real coral - we want to protect it! So do an experiment - Give it a try!

Can’t plants take care of the CO₂?
People are releasing CO₂ at levels far higher than the regular levels produced by any natural processes involving plants, animals, air, or water. While regular levels of CO₂ stay constant over hundreds of thousands of years, rampant CO₂ builds up through our burning of fossil fuels, like coal, oil and natural gas. We call this rampant CO₂ because there is too much of it and it is out of control. It builds up too quickly for natural processes to balance it out. This rampant CO₂ acts as though it is thickening a heat-trapping blanket around our Earth, causing our planet and our oceans to get warmer.

Is the bleached coral dead?
The bleached coral isn’t dead, but it is sick and hungry and if conditions don’t change, the coral can die. Fortunately, we know that by collectively acting to reduce rampant CO₂ emission that comes from the burning of fossil fuels, we can actively reduce the risk to coral reefs, and safeguard the entire interconnected ocean system that supports people and ecosystems around our Earth.

What can we do to help?
The key to getting the climate system back to functioning the way it should is to get away from fossil fuels for energy. This means moving towards clean energy sources, such as wind and solar. These sources don’t add to that heat-trapping blanket effect! Here in California, as a state, we are moving in a stepwise manner towards having our energy sector produce at least a third of our electricity from sources other than fossil fuels. We are proud that the city of San Francisco is also a leader in reducing the use of fossil fuels. Thanks to an environmentally engaged community, the city launched CleanPowerSF, which now provides 48% clean energy to all San Francisco homes, with the option of upgrading to 100% renewable energy! Many other California cities offer similar choices. We can support this in our own communities by staying informed of the options available to us, and by choosing clean energy when available. As we talk about it with each other, with landlords, and with civic leaders, we will make it clear that we expect clean energy delivered to our homes! By changing how we get our energy, we can protect ecosystems near and far, including our amazing coral reefs!