for National Geographic News
Pollution from industrialized countries is heating the Arctic atmosphere faster than any region on Earth, a new study warns.
European researchers writing in today's issue of the journal Science report that temperature spikes in the Arctic are mainly caused by "human-induced emissions of long-lived greenhouse gases."
Ship emissions, smoke from summer forest fires, and air pollutants such as aerosols and ozone coming from the lower latitudes are contributing to "significant warming trends," the report authors say.
Surface air temperatures in the region have risen faster than the global average over the past few decades and "are predicted to warm by 5 degrees Celsius [9 degrees Fahrenheit] over a large part of the Arctic by the end of the 21st century," the authors note in their study.
Previous climate models have suggested that the Arctic's summer sea ice may completely disappear by 2040 if warming continues unabated.
"The Arctic is at risk because global warming is proceeding fastest there," said study co-author Andreas Stohl of the Norwegian Institute for Air Research.
"This is mainly a consequence of the increasing trends of long-lived greenhouse gases and feedbacks in the climate system, which are strongest in the Arctic."
Even though the Arctic receives a large amount of sunlight in the summer, the high reflectivity of its snow and ice surfaces usually keeps the ground from absorbing much of the heat.
But the Arctic atmosphere is dry and stable, which allows long-lasting aerosols and trace gases arriving on the wind to more easily build up and form what's known as the Arctic haze.
This haze of pollutants absorbs heat from sunlight and can speed up warming.
The light that passes through the haze and reaches the highly reflective snow and ice is bounced back through these gases, offering greater opportunity for them to capture the sun's heat.
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