Why is glacial ice blue?
Glacial ice appears blue because compacted ice absorbs most wavelengths of light and reflects blue light. The deepest blue ice is found in crevasses. PLEISTOCENE The Pleistocene – The Last Ice Age About 1.8 million years ago, the Last Ice Age began. A period of long-term cooling of Earth’s climate resulted in the expansion of continental and polar ice sheets and mountain glaciers. As much as 30% of all the continents were covered by glaciers and parts of the northern oceans were also frozen. During this Ice Age, no massive ice sheets covered California. Glaciers were confined to high mountains, advancing and retreating 4 to 7 times. The Last Ice Age ended just 10,000 years ago, but several small glaciers still persist in California at high elevations. High concentrations of gases like methane and carbon dioxide in the atmosphere trap heat radiating from Earth. Decreased levels of these gases, especially carbon dioxide, could have contributed to the onset of ice ages by cooling Earth’s
