Previous Year Question
Which one of the following provides the cryogenic indicator of climate change?
Ice core
Fossilized pollen
Tree ring growth
Evaporite deposits
Correct Answer: A
Detailed Solution
An Ice Core is a cylindrical sample of ice obtained by drilling into a glacier or Ice Sheet. Layers of ice accumulate over time and can preserve a record of the environmental and atmospheric conditions that existed when those layers were formed.
The air bubbles trapped within Ice Cores act as actual samples of the ancient atmosphere. Their study provides information about past concentrations of Carbon Dioxide (CO₂), Methane (CH₄) and other atmospheric gases.
Oxygen Isotopes, dust, volcanic ash and other chemical constituents preserved in ice can be used to reconstruct past temperature, precipitation, volcanic activity and atmospheric composition. Therefore, Ice Cores are important Paleoclimate Proxies.
Ice Core records from Antarctica provide atmospheric and climate information extending back approximately 800,000 years.
The other options can also provide information about past climate, but through different mechanisms. Fossilized Pollen is a biological proxy of vegetation and climate conditions, while Tree Ring Growth is a dendroclimatic proxy of factors such as temperature and moisture.