Study Shows the link between Arctic Warming and Reduced Sea Ice and Global Atmospheric Warming
According to Professor Ian Simmonds of the University of Melbourne, it is a combination of the melting sea ice and the atmospheric warming that is happening globally that is responsible for the high rate of warming in the Arctic.
The temperatures in the arctic are rising four times faster than the global average, says a study done at the University of Melbourne's School of Earth Sciences.
“Loss of sea ice contributes to ground level warming while global warming intensifies atmospheric circulation and contributes to increased temperatures higher in the Arctic atmosphere,” Professor Simmonds said.
He went on to point out that the intensity of atmospheric circulation is increased in step with the increase in global temperature. Simmonds stated, “This circulation transports energy to the Arctic region, increasing temperatures further up in the atmosphere.”
Sea ice acts like a shiny lid on the Arctic Ocean says lead author of the study, Dr. James Screen, “When it is heated, it reflects most of the incoming sunlight back into space. When the sea ice melts, more heat is absorbed by the water. The warmer water then heats the atmosphere above it,” he said.
The study points out that water vapor is a very powerful greenhouse gas, and as the atmosphere warms, its ability to hold more moisture increases. This acts as a positive feedback signal, increasing the greenhouse effect, according to the study. But, the study also points out that the colder temperatures in the arctic hamper the greenhouse effect because of less moisture in the atmosphere, so the positive feedback effect is weaker.
Although, Professor Simmonds says, “Even though the Arctic region has a relatively small greenhouse effect, the effect of the melted ice combined with greater transports of heat from the south are more than enough to make up for this modest ‘local’ greenhouse warming.”
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