Directions : Read the summary, watch the videos and answer the discussion questions below. You may want to turn on the "CC" (closed-captions) function and read along with the transcript here .

Summary: To understand the history of climate change, researchers are digging underneath the ocean floor where organisms and plants have accumulated in sediment over millennia. Columbia University’s Lamont-Doherty Earth Observatory holds samples taken from the Earth’s ocean floor, a collection that has taken over half a century to build. One of the great scientific advances that came out of the Lamont core repository was the proof of the theory of the ice ages and this understanding that the ice ages come and go caused by variations in the Earth's orbit around the sun.

"So right now, the Earth's orbit should be making the Earth cooler in the Northern Hemisphere," according to Maureen Raymo, a marine biologist and director of the core repository, "And we're observing it's warmer, and that's obviously because we're putting so much greenhouse gases into the atmosphere very quickly." The repository collects samples from oceans all around the world and sends them to scientists to study. There are still many places to explore and many uncertainties about what happened in the past especially around Antarctica.

Discussion questions:

1. Essential question : How does exploring the ocean's floor teach scientists about climate change?

2. What impact does the core repository have on scientific research like climate change?

3. Maureen Raymo discussed how the repository was developed and how it's difficult to raise the funding to go out and do a scientific expedition. "So, if you can do your work with material that already exists, that's a big win for science,” she said. What are the benefits of having a "living museum" collection that includes both new and old material?

4. Raymo will be leaving soon for an expedition to find cores in Antarctica. What do you think scientists will find at the polar ice caps given the effects of climate change? How do you think the Antarctic Ocean’s geology will differ from the oceans that scientists have researched previously?

5. Media literacy : Today's media literacy questions are brought to you by IREX visiting teachers from Britain who visited the PBS NewsHour studios on April 9, 2019.

a. Give a few examples of words that may be considered biased. Most of us have a viewpoint on an issue, and awareness of our bias is important in media literacy. You may want to use the transcript here to help you.

b. What role did experts play in this story? How important is it for a news story on climate change to include experts?

c. What are the credentials of the scientists featured in the story? How could you find out, if you are not sure?

Extension Activities:

Check out these articles on climate change, including this first one which discusses Columbia's Lamont-Doherty Earth Observatory: Without human-made climate change, U.S. forest fires would be half the size. To dig deeper into the UN's latest report on climate change, read the article, Worsening environment is deadly but not hopeless, UN report says .

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