The Role of Ice in the Ocean: Pt. I: What is Sea Ice and Why Is It Shrinking?


NOAA Office of Oceanic and Atmospheric Research

NOAA Climate Program Office

NOAA Office of Ocean Exploration and Research

National Snow and Ice Data Center

NASA's Operation Ice Bridge

The Hidden Ocean, Arctic 2005 Exploration

NASA/Goddard Space Flight Center Scientific Visualization Studio

Dr. Aleksey Ostrovskiy

Benjamin Jones - USGS

Footage Search - Daniel Zatz, Ernie Kovacs

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The Arctic region is hauntingly beautiful. It's a vast expanse of sea ice floating on water. Sea ice is actually frozen ocean water. It forms, grows, and melts in the ocean.

Arctic sea ice plays a major role in the Earth's global systems. It keeps the polar regions cool, influences climate, and provides a habitat for many animals.

But the amount of sea ice in the Arctic has been on a steady decline over the past two decades. In fact, the annual minimum area of sea ice is nearly 50% smaller now than it was in 1979.

So why is the sea ice shrinking? Arctic sea ice is melting at an alarming rate because ocean and air temperatures are getting warmer. Here's how:

The burning of fossil fuels emits carbon dioxide and other heat-trapping gases into the atmosphere. The heat absorbed by these gases is radiated back towards the Earth's surface. Then, the ocean absorbs this heat from the air. As the ocean heats up, sea ice melts.

The more the ice melts, the more ocean surface is exposed to the sun's rays. Unlike sea ice that reflects the sunlight back into the atmosphere, the dark surface will absorb it, warming the region further. The cycle of warmer temperatures and ice melt continues.

In fact, air and ocean temperatures are rising faster than at any other time in history.

If we are to understand how much and how fast the ice is melting, we need to be able to accurately measure it.