Midterm 1 Tipping Points Flashcards
Tipping Points
Parts of climate that can jump states when crossing a climate threshold
The change after
crossing the threshold
could be _________, depending on
the time scale of the
system
abrupt or
slow
The tipping point
could be _____
(turning back below
the threshold flips the
system back)
or irreversible (there
is a different, even
lower threshold to flip
the system back)
reversible
Tipping point
might not be
clear until after
you’ve already
____ it
Difficult to predict tipping points because they are so finely tuned
passed
Deep ocean conveyor belt -
could abruptly turn on or off depending on North Atlantic salinity
could abruptly turn on or off depending on North Atlantic salinity
will overturn if North Atlantic water is salty enough to sink
Arctic permafrost – warming melts permafrost / ice, frozen ____ released, amplifies warming, etc.
carbon
Greenland Ice Sheet – big and stable at lower temperatures, destined to melt above a certain
temperature when snowline rises above ice sheet
The ice sheet only exists because
more snow falls on it than can melt
away in the summer (i.e., the
accumulation zone). If the snowline
rises above top of ice sheet with
warming, it will no longer accumulate
any ice and is destined to melt away
Slow - it will take at least centuries to melt
Irreversible – once gone, ice has to
regrow starting from warmer,
lower elevations, so there is a
second, lower tipping point for
that
West Antarctic Ice Sheet – mostly rests on land ____ sea level that slopes down toward center of
continent; if it starts retreating on this reverse sloping bed, discharge rate increases, causing further
retreat, etc.
some parts of the West Antarctic Ice Sheet may already be at the tipping point
below
Amazon forest dieback – warming kills part of forest, fewer trees now able to ____ moisture back into
atmosphere to rain again, drying kills more forest, results in the loss of a big carbon sink
recycle
