Why Is the Arctic Warming So Much Faster Than the Antarctic?
I was asked this question the other day by a moderate climate skeptic and realized that while people may have read this fact in passing (generally called Arctic Amplification), the scientific reasons for it are not usually explained. The answer is fairly simple: it’s about geography.
The “top” of the planet is dark ocean – open water – while the “bottom” of the planet, Antarctica, is a continental land mass almost twice the size of the United States. The area around the North Pole is normally covered by sea ice, which reflects about 90% of the sun’s heat energy back into space. This reflectivity is called albedo.
The Arctic Ocean has lost about 40% of its ice in the past four decades.
However, as the disappearance of sea ice has accelerated in recent decades, there is less ice in the Arctic ocean and more black open water to suck in the sunlight. The dark water absorbs significantly more incoming solar energy, which causes faster warming of the water, which in turn melts more ice, which opens more water up.
This is one of the primary Climate Feedback Cycles. It feeds on itself and it affects global weather. As the sea ice disappears, currents and prevailing wind patterns are massively disrupted, causing more extreme weather and prolonged meteorological events such as droughts.
In Antarctica, the scenario is different. Although the interior glaciers are melting and the coastal ice shelves that hold them back are virtually collapsing, there are trillions of tons of reflective snow and ice sitting on a vast land mass. At the South Pole, only about 30% of the solar energy is absorbed, with the remained reflected back into space.
Hence the disparity in warming rates at the two opposite ends of the planet.