Chapter 1 WHAT IS ARCTIC SEA ICE The Arctic Ocean covers the most northern part of Earth It is the smallest shallowest and coldest of the five oceans Arctic sea ice is frozen ocean water that forms grows and melts in the ocean Every year ice in the Arctic goes through a growth and melting cycle It grows to its largest extent around March and melts to its lowest extent around September
The Arctic is one of the environments most at risk to climate change Earth's climate can change due to natural factors like volcanoes weather patterns and the position of Earth to the sun But scientists agree that human activity is the main factor causing Earth's climate to change As Earth's climate changes so does the Arctic Austfonna located in Norway's Svalbard archipelago is one of the largest ice caps in northern Europe
Measuring Ice Researchers from the National Snow and Ice Data Center measure Arctic ice because it tells them about climate change They study how far the ice extends and how much ice grows in a certain area They also measure how thick the ice is above and below the surface Younger ice is thinner and more likely to melt in the summer months than older thicker ice Many Alaskans use unghaqs ice testing sticks when they walk and hunt on the ice so they can test the ice's thickness and move safely
Polar researcher Roman Gouzenko drills into Arctic ice Scientists measure ice in multiple ways They collect data recorded from satellites The data has been recorded since 1978. Satellites measure how much ice covers the Arctic in all seasons Newer satellites give estimates for ice thickness but there is not yet long term data For a closer look field researchers drill holes deep into the ice The oldest ice can be up to 15 feet 4.6 m deep They also pull sleds with sensors The sensors send electromagnetic pulses or short bursts of energy into the ice to estimate the thickness of the ice below Buoys that float on the sea ice or in Arctic waters also collect data
