2. One feedback, the ‘albedo flip’ property of
ice/water, provides a powerful trigger mechanism.
A climate forcing that ‘flips’ the albedo of a
sufficient portion of an ice sheet can spark a
cataclysm.
Climate change and trace gases JAMES HANSEN et al 2007
3. Three large sources of Arctic albedo cooling
> Far North snow cover > Summer sea ice extent > Greenland ice sheet surface
Snow
Sea
Open ice
ocean
Exposed
land
2012 record Arctic summer sea ice loss
4.
5.
6.
7.
8.
9.
10. Arctic summer albedo is the ‘air conditioner ‘
for the entire Northern hemisphere
11. Loss of Arctic cooling is the first of a series
of strong Arctic +ve (bad) feedbacks
Arctic climate positive (bad) feedbacks are caused by
the very rapid warming of the Arctic region due to
global warming, which is now 3 to 4 times the rate of
global warming.
The effect of the multiple Arctic feedbacks is to amplify
the Arctic warming, Northern hemisphere warming
and to some extent global warming.
The Arctic +ve feedbacks
us
1. Snow albedo spring summer cooling loss of (about
the same warming as sea ice loss).
2. Sea ice albedo summer cooling loss of the sea ice
Loss of, would be about one third of the warming by
CO2. The extent is about the same as the permafrost.
3. Peat rich wetlands warming increases emissions
of methane (70 times CO2 warming over 20 years).
4. Permafrost methane emissions from thawing
(permafrost has double all atmospheric carbon).
5. Permafrost nitrous oxide emissions from thawing
cryoturbation.
6. Methane hydrate - Emissions of methane from
destabilized ‘melting’ sea floor frozen solid Arctic
methane gas hydrates (1 to 2 times atmospheric
carbon).
12. All Arctic sources of feedback methane emissions are releasing more
methane, in relatively small amounts today- but this will be greatly
increased with continued rapid loss of Arctic snow and ice albedo
cooling.
13. Loss of Arctic cooling is the first of a series
of strong Arctic +ve (bad) feedbacks
The loss of
Arctic snow and Warming
summer sea ice peat rich
albedo, by wetlands
increasing Arctic
warming, will
increase the
rate of Arctic
Thawing
methane (and permafrost
CO2) feedback
emissions,
and the rate of Melting sea
Greenland ice floor
sheet melting methane
hydrate
14. The loss of Arctic
albedo is a
+ve feedback
Snow and ice
reflect almost
all incoming
solar energy
back out to
space .
Snow is the
very best
reflector
there is.
15. Arctic summer sea ice albedo cooling
Less sea ice extent
More thin ice
More dark open
water Open Sea
ocean ice
2012 record Arctic summer sea ice loss
16. Feedback
As snow and
ice melt away
this cooling
effect
lessens-
resulting in
warming
This is
positive feed
back effect of
global
(Arctic)
warming
17. Thin first
year or
melting ice
has less
albedo than
thick multi
year ice.
Therefore
thinning of
the ice as well
as decreasing
ice extent
reduces
albedo.
Thin ice
less albedo
18. Feed Dark open ocean water is the best absorber of
heat energy there is.
back
It absorbs almost all the incoming solar energy
as heat.
Dark ocean
water opens This warms the Arctic surface sea water and
up as sea ice the air above it.
melts away
which
absorbs
Heat.
.
Dark open water
19. Feed
back
Melting ice
requires a
tremendous
amount of energy
to force the
physical phase
change of solid
ice to liquid Latent heat
water.
of ice
This is using up a
lot of the solar
energy during the
Arctic summer ,
that will become
available to cause
more surface
warming as more
ice is melted.
20. Feedback
The layer of intact sea
ice insulates the ocean
water from warmer air
above in the Arctic
summer. Insulating
layer of sea
As sea ice melts this ice and snow
insulation is lost.
21. Loss of Arctic snow and summer sea ice
albedo positive feedbacks
Dark open water
Thin ice
less albedo
