Differential Heating on Planet Earth
Published in the EarthSphere Blog – Cover Image: Beach Walking by the Barents Sea (©Archean Enterprises, LLC; ArcheanArt)
The Barents Sea has been called the fastest warming place on Earth. But apparently, not too many people are worried. This lack of concern is understandable given the Barents Sea’s location. The entire sea is above the Arctic Circle, with the Kara Sea on its east flank, the Greenland Sea to the west, and the Arctic Ocean capping it on the north. South of the Barents Sea lies land. A small protrusion of Europe where Norway, Sweden, Finland, and Russia crowd in together in a chilly little love-fest above the Arctic Circle.
It’s safe to say that few people plan their summer beach vacations there, and sunbathing is out of the question most, if not all, of the year. College students on spring break vie for South Beach, not the shores of the Barents Sea. So it is a cold icy little piece of our planet. Despite its inhospitable demeanor, it has gained the distinction of setting a global record for warming.
To provide a little context, I will remind my readers that the Arctic is heating up about three times faster than the rest of the planet. But the northern Barents Sea is heating up 2 to 2.5 times faster than the rest of the Arctic. This double-whammy means the Barents Sea is warming at a rate between 5 and 7 times the global average. Before you pack your swimsuit and head north, I should mention the sea ice.
Sea Ice
Sea ice in the Barents Sea should not be confused with Antarctic ice shelves, which can be thousands of feet thick. Sea ice gets up to several meters thick and covers the ocean surface with a decorative white blanket. The extent of the ice waxes and wanes throughout the year, with the ice cover expanding in the winter and shrinking in the summer. This delicate dance is extremely important in understanding the current warming dilemma.
The presence or absence of ice affects the albedo of the ocean surface. Albedo simply refers to the ability of a surface to reflect light. Surfaces reflecting lots of light are said to have a high albedo. Ice, being white, has a high albedo and reflects much of the incoming solar radiation, returning it to space.
The physics of this situation is easy. Reflected solar radiation doesn’t hang around to warm the planet. Specifically, it can’t warm the Barents Sea. But the situation is reversed when the ice melts. Open ocean water is dark in color and absorbs a lot of solar radiation, hence lots of heat.
The Barents Sea finds itself in a difficult situation where less sea ice is forming each winter, creating a feedback loop where the extra heat absorbed by the summer ocean continuously melts more ice than reforms in the winter. In short, the Barents Sea is suffering from the ‘Disappearing Sea Ice Blues.’
Not Good News
For many people, the Barents Sea seems a distant problem, and the temptation is to not worry and be happy. There is nothing wrong with being happy, but sadly what happens in the Arctic does not stay in the Arctic. The Arctic has the meteorological distinction of controlling much of the northern hemisphere’s weather.
The thin atmospheric shell surrounding Earth is capped at the North Pole by the Arctic Vortex. This atmospheric vortex keeps the jet stream continuously zipping in a circle around the planet. We can think of the jet stream as a barrier keeping cold air in the Arctic and separating it from warmer air to the south. The stronger the jet stream, the stronger the barrier.
But the strength of the jet stream is related to the temperature differential between the Arctic and the mid-latitudes. When the Arctic, including the Barents Sea, heats up, the temperature differential drops, and the jet stream weakens. As it weakens, it meanders, forming large loops, pushing cold air far southward into places like Texas and Florida and forcing hot air into usually cold regions such as Siberia.
Usual weather patterns are disrupted as Siberia burns and the Texas electrical grid collapses from an unexpected freeze. Does this sound familiar? It should. A warming Arctic is everyone’s problem because what happens in the Arctic doesn’t stay in the Arctic.
Sources:
New data reveals extraordinary global heating in the Arctic (Source: The Guardian)