A University of Melbourne study has shown that melting sea ice and overall warming across the globe are contributing to temperatures in the Arctic region rising up to four times faster than the global average.
The researchers say that while melting of sea ice contributes to ground level warming in the Arctic, global atmospheric warming increases atmospheric circulation, which in turn raises the temperatures.
Professor Ian Simmonds from the university's School of Earth Sciences said, "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."
The sea ice acts as a shiny lid on the Arctic Ocean. "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," said Dr. James Screen, the lead author of the study.
At the same time, as temperatures across the globe increase, the atmospheric circulation transports thermal energy to the Arctic region, thus adding to the region's high rate of increase.
"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," the researchers noted.
The study was published in the Geophysical Research Letters and featured in Nature.
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