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The area surrounding the North Pole
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may seem like a frozen and desolate
environment where nothing ever changes.
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But it is actually a complex
and finely balanced natural system,
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and its extreme location
makes it vulnerable to feedback processes
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that can magnify even tiny changes
in the atmosphere.
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In fact, scientists often describe
the Arctic as the canary in the coal mine
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when it comes to predicting the impact
of climate change.
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One major type of climate feedback
involves reflectivity.
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White surfaces, like snow and ice,
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are very effective at reflecting
the sun's energy back into space,
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while darker land and water surfaces
absorb much more incoming sunlight.
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When the Arctic warms just a little,
some of the snow and ice melts,
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exposing the ground and ocean underneath.
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The increased heat absorbed by
these surfaces causes even more melting,
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and so on.
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And although the current situation
in the Arctic follows the warming pattern,
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the opposite is also possible.
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A small drop in temperatures
would cause more freezing,
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increasing the amount
of reflective snow and ice.
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This would result in less sunlight
being absorbed,
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and lead to a cycle of cooling,
as in previous ice ages.
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Arctic sea ice is also responsible
for another feedback mechanism
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through insulation.
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By forming a layer on the ocean's surface,
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the ice acts as a buffer between
the frigid arctic air
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and the relatively
warmer water underneath.
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But when it thins, breaks,
or melts in any spot,
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heat escapes from the ocean,
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warming the atmosphere
and causing more ice to melt in turn.
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Both of these are examples
of positive feedback loops,
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not because they do something good,
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but because the initial change
is amplified in the same direction.
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A negative feedback loop,
on the other hand,
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is when the initial change
leads to effects
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that work in the opposite direction.
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Melting ice also causes
a type of negative feedback
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by releasing moisture into the atmosphere.
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This increases the amount and thickness
of clouds present,
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which can cool the atmosphere
by blocking more sunlight.
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But this negative feedback loop
is short-lived,
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due to the brief Arctic summers.
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For the rest of the year,
when sunlight is scarce,
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the increased moisture and clouds
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actually warm the surface
by trapping the Earth's heat,
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turning the feedback loop positive
for all but a couple of months.
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While negative feedback loops
encourage stability
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by pushing a system towards equilibrium,
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positive feedback loops destabilize it
by enabling larger and larger deviations.
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And the recently increased impact
of positive feedbacks
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may have consequences
far beyond the Arctic.
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On a warming planet,
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these feedbacks ensure that the North Pole
warms at a faster rate than the equator.
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The reduced temperature differences
between the two regions
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may lead to slower jet stream winds
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and less linear atmospheric circulation
in the middle latitudes,
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where most of the world's
population lives.
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Many scientists are concerned
that shifts in weather patterns
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will last longer and be more extreme,
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with short term fluctuations becoming
persistent cold snaps,
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heat waves, droughts and floods.
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So the Arctic sensitivity doesn't just
serve as an early warning alarm
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for climate change
for the rest of the planet.
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Its feedback loops can affect us
in much more direct and immediate ways.
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As climate scientists often warn,
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what happens in the Arctic
doesn't always stay in the Arctic.