Meltdown, Earth Meltdown?
say the Arctic is changing right now. They point to rises
in temperatures, decreases in the extent of annual snow and
ice cover, thinning of glaciers and sea ice. That's too bad
for the Arctic, but does it really affect the majority of
us who live at lower latitudes and may never see the land
of the midnight sun? In a word, yes. Polar regions play a
major role in the climate of the entire planet.
global temperature gradient causes atmospheric circulation,
with heat flowing from the equatorial regions toward
the poles. This circualtion drives our weather patterns.
average, the north and south poles receive less solar radiation
than areas near the equator. Because of the tilt of our spherical
planet's axis, the sun's rays hit the poles at a more oblique
angle than they do in the tropics. And because of albedo,
the icy polar regions are also reflecting more of whatever
solar radiation reaches them back to space than are equatorial
regions. There's more solar radiation leaving the atmosphere
in the arctic than there is entering. So the atmosphere at
the Earth's surface in the Arctic will be colder, on average,
than it is at lower latitudes. This global temperature gradient
causes atmospheric circulation, with heat flowing from the
equatorial regions toward the poles. The atmosphere strives
for equilibrium, that is, for all areas on the globe to be
about the same temperature. Warm ocean currents also carry
heat to the higher latitudes.
all of the earth's weather is caused by these circulation
patterns. And they're driven by the fact that the poles are
currently heat sinks. If the Arctic warms up, the temperature
gradient from the equator to the North Pole would get weaker,
and that would cause weaker circulation patterns. The weather
is notoriously hard to predict - just think about your local
five-day forecast - so it's impossible to say what a future
with weaker atmospheric circulation will look like. But it
will definitely be different than the world we live in now.
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