February 26, 2011
So how is it that we know about past climate on the Earth? Nowadays we have satellites that monitor patterns and conditions in the land, atmosphere, oceans, and polar regions. But what about before satellites? Today we learned that scientists study ice and sediment cores to learn about past climates.
Basically, each year ice and sediment settle into layers. If you drill down deeper and deeper into ice or sediment, each layer tells us what the climate was like further and further back in time. In that way, ice and sediment cores are kind of like a time machine!
Today Bryan Mark from the Byrd Polar Research Center at the Ohio State University talked to us virtually through Second Life. (So really it was his avatar talking to all of our student avatars.) He talked to us about his research in paleoclimatology (an official way of saying he studies Earth’s long-term climate record), and his research in the connection between glaciers, climate and Earth’s water resources. Dr. Mark actually goes to Peru to study tropical glaciers in the Andes Mountains!
We also got to make models of time machines (aka sediment cores). Using everyday stuff like gravel, dirt, ice, and clear plastic tubing, we actually mixed up the materials in three different combinations, and deposited them so they made three distinct layers. These layers represented three different conditions: an ice sheet (ice over solid land), an ice shelf (ice floating on water), and the open ocean. In real sediment cores, when scientists see indications of these conditions, in this order, it shows that the climate was warming up over that time period.
How amazing! We can “tell time” by rocks and ice! That is exactly what climate scientists like Dr. Mark are doing.