NOVA Online | Tracking El Niño | What else can ice cores tell you?

What else can ice cores tell you?

Scientists can measure concentrations of two greenhouse gases—carbon dioxide and methane—trapped within air bubbles in the ice. This can help tell them how long the greenhouse effect has been around and help them predict how much may be part of natural cycles versus effects produced induced by humans. Scientists can also measure hydrogen peroxide in ice cores taken from locations with distinct seasons to determine where the annual layers are. Hydrogen peroxide is created by a chemical reaction that requires ultraviolet light—the higher the concentration of hydrogen peroxide, the more likely the layer was formed in summer when there is more light. The tephra (volcanic ash) and sulfate in the ice allow reconstruction of the earth's volcanic history long before humans were around to observe and document eruptions. At low latitudes these layers can also preserve pollen, organic matter, and even insects!