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When is the Permafrost
Carbon Tipping Point?
National Snow and Ice Data Center, Universit of Colorado
Ting!"n
#hang
Kevin Schaefer
Tim
Schaefer $in $i"%e
&lessio
'"smereli
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Permafrost Primer
Skiklomanov [2007]
Permafrost: 'round at or
below 0°C for at least 2
consecutive years
Active ayer: & layer over
!ermafrost t"at free#es and
t"aws annuallyPermafrost $e%radation: &
decrease in !ermafrost
e&tent' an increase in active
layer t"ickness(
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Permafrost Classification
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Permafrost Classification by AreaPermafrost Classification by AreaContin"o"s ()*+ of area-
Discontin"o"s (.+/*+ of area-
Sporadic (0+/.+ of area-Isolated (10+ of area-
Brown et al 2, 0**34 Zhang et al 2, 0***
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Permafrost Distrib"tion b Co"ntr
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Permafrost ProfilePermafrost Profile
Active Layer
Vegetation
Permafrost
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Permafrost Profile
56posed permafrost b river, Siberia
7Davis, 8+++9
Thermo:arst, &las:a
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Crot"rbationCrot"rbation
; %ovement of soil or roc: d"e to%ovement of soil or roc: d"e to
repeated free
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Permafrost =eat"resPermafrost =eat"res
Frost Heave, Yamal Stone Circles, Svalbard
Stone Circles, NW Territories Stripes, Glacier NP
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Ice Wedges and PolgonsIce Wedges and Polgons
Poly%ons) *ena Poly%ons) Prud"oe +ay [,"an%) 200-]
Active Layer
Permafrost
Frozen
100th Winter
Frozen
1st Winter
Soil contracts& cracks
Thawed
1st Spring
Crack fills withwater & freezes
Thawed
100th Spring
Ice
Wedge
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Ice $enses and $aersIce $enses and $aers
Active Layer
Permafrost
Year 1
Capillary
suction of
water to
permafrost
Water freezes
& expands
Year
1,000
Ice Layer
Ice Lens
Active Layer
Permafrost
Ice Lenses
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Permafrost is $i:e ConcretePermafrost is $i:e Concrete
WicklandSchaefer
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Thermo:arstThermo:arst
Slo!e .ountain) Alaska [Sc"aefer) 20/2]
; Thermokarst > s"bsidence or collapse of gro"nd
s"rface d"e to melting of gro"nd ice
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Impacts of DegradationImpacts of Degradationoundation Settlin%
in C"ersky
1in%"ai3i#an% 4i%"way +rid%e
Alaska 5oad 4eaves
6"ermokarst in *akutsk [Skiklomanov) 200]
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Impacts of DegradationImpacts of Degradation
Dring la:e, Tibet 7#hang, 8++9
@oc:fall, %atterhorn 7'r"ber, 8++A9 Ice/wedge thaw, &las:a 7Davis, 8+++9
Coastal 5rosion, &las:a
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'lobal Carbon Ccle'lobal Carbon Ccle
0202* *+ 33
Bcean
A3,+++ 't
=ossil ="el
+++ 't
Permafrost 0 't
&tmosphere
.+ 't E A 't r /0
00*08+
Soils 0++ 'tFegetation ++ 't
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Permafrost Carbon G"rial
PermafrostHori
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Permafrost Carbon
A+,+++ ear old roots, Siberia7#imov et al2, 8++9%ammoth, Siberia
A8,+++ ear old grass, &las:a 0.,+++ ear old moss, North Slope
7Schaefer , 8+089
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Permafrost Carbon =eedbac:
&mplification ofwarming d"e to release
of CB8 and CH from
thawing permafrost
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%ethane @elease from Thawing Permafrost
K. Walter [email protected]
Thaw b"lb
Permafrost
Peat
Methaneproduction
Methane
emissionemissio
n Thermokarst
Erosion
Dead
plant &
animal
remains
+urnin% met"ane over a
t"ermokarst lake in
Siberia 89( alter;
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IPCC &0G Scenario
200
300
400
500
600
700
800
160 2000 2040 2080 2120 2160 2200
Date (ear-
& t m o s p h e r i c
C B 8 ( p p m -
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C"rrent Permafrost
&ctive $aer Thic:ness &$T (cm-&ctive $aer Thic:ness &$T (cm-
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Pro!ected Permafrost DegradationHadC%A (med-HadC%A (med-
&ctive $aer Thic:ness &$T (cm-&ctive $aer Thic:ness &$T (cm-
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Pro!ected Permafrost $oss
CCS%A (low-CCS%A (low-8* loss8* loss
HadC%A (med-HadC%A (med-.+ loss.+ loss
%I@BCA28 (high-%I@BCA28 (high-.* loss.* loss
Increase in &$T b 88++ (cm-Increase in &$T b 88++ (cm-
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Permafrost Carbon Tipping Point
PC= Tipping
Point 8+8AJ
Date (ear-
C " m " l a t i v e
N 5 5 ( ' t C -
&rctic switches from a sin: to a so"rce
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C"m"lative Permafrost Carbon =l"6
Date (ear-
P e r m a f r o s t C a r b o n = l " 6 ( ' t C -
0*+J
't
0+JA 't
.J8A of c"m"lative global land sin: (0+ 't C-5K"ivalent to 3J8* ppm
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Fosto: Ice Core @ecords
; CB8 lags behind temperat"re b ++J++ r
3+ ppm
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Paleo/Permafrost Carbon =eedbac:
Palaeocene
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PC= and =ossil ="el 5missions
; Goth in!ect old carbon into atmosphere
; Goth irreversible
; &0G scenario> ++ ppm b 80++; 0A. 't C total emissions
; 0*+ 't C permafrost carbon fl"6
; 00. 't C fossil f"el emissions
; %"st red"ce fossil f"el emissions b additional0. or overshoot target climate
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Concl"sions
; PC= can e6plain past climate variabilit
; PC= tipping point in mid 8+8+s
; PC= is strong> 0*+J 't C b 88++
; 5mission red"ctions m"st acco"nt for PC=
; Tell"s G paper> Schaefer et al2 78+009
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Gac:"p SlidesGac:"p Slides
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The SiGC&S& %odelThe SiGC&S& %odel
CB8 Temp
H"midit
N55$atent
Heat
Sensible
Heat
Snow
@
% o i s t " r e
T e m p e r a t " r e
C
a r b o n
Canop
Soil
'PP
Inp"t
Weather
Go"ndar $aer
f b i i
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Permafrost Carbon in SiGC&S&
Dmin L ma6 &$T
d"ring spin"p
&ctive $aer
Thic:ness (&$T-
Soil
Carbon
Pools
Dmax L A m
&ctive $aer
Permafrost
Thawed Carbon
PermafrostCarbon Pool
&ctive $aer
Permafrost
Carbon Pool
Permafrost
; A0A 't C in permafrost carbon pool
; *0 't C in active laer
; 0 't C in top A m (.. 't C estimatedM-
MTarnocai et al. 78++*9
i S
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56periment Set"p
; SiGC&S& E 5@&+ E &0G scenario
; Contin"o"sdiscontin"o"s permafrost
; 0*A/8++0> Ospin "pO
; 8++8/88++> random 5@&+ E linear trend; %I@BCA28 (high-
; HadC%A (med-
; CCS%A (low-
5 i i U i
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5stimating Uncertaint
; 03 ensemble members; A warming rates
; A permafrost carbon densities
; 8 s"b/grid permafrost e6tents; Gest estimate> ensemble mean
; Uncertaint> ensemble standard deviation
IPCC &0G & i T
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IPCC &0G &rctic Temperat"res
& i r T e m p e r a t " r e ( C -
CCS%A (low warming-
HadC%A (medi"m warming-
%I@CA28 (high warming-
&verage air temperat"re for permafrost regions
P f & $
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Permafrost &rea $oss
Date (ear-
P e r m a f r o s
t & r e a ( , -
0*J. 't C8+AJA 't C 80AJ. 't C
= ' d 5= ' d 5
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=ro
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Atmos!"ere
=e%etation
Snow cover
>eot"ermal
?r%anic layer
Permafrost
+uffer
ayer
"at $rives Permafrost ormation@"at $rives Permafrost ormation@
G
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Garrow,Garrow,
&las:a&las:a
Bbserved Soil
Temperat"re (C-0**/
%onth
S o i l D e
p t h ( m -
S n o w
D e p t h ( c m -
& i r
T e m p ( C -
Soil Temperat"re (C-
Bbserved Snow
Depth (cm-
8++8/A
Bbserved &ir
Temperat"re (C-
8++A/
epeate o ree
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epeate o ree settling of gro"nd s"rface
when gro"nd ice meltswhen gro"nd ice melts
; Moisture Movement > soil moist"re moves from> soil moist"re moves from"nfro
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Permafrost =eat"resPermafrost =eat"res
Frost Heave, Yamal Stone Circles, Svalbard
Stone Circles, NW Territories Stripes, Glacier NP
P f t D d ti 7IPCC 8++9P f t D d ti 7IPCC 8++9
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Permafrost Degradation 7IPCC, 8++9Permafrost Degradation 7IPCC, 8++9
)A C increase
mid/0*.+s to 0**+
0 to A C increase
in past several
decades
+ to 0 C increase
since 0*+s
to C increase in 8+th Cent"r
8 to A C in last A+ ears
@ i P f t T t T d@ i P f t T t T d
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/
/A
/8
/0
+
0
8
A
0*.+ 0*.. 0*+ 0*. 0*+ 0*. 0*3+ 0*3. 0**+ 0**. 8+++
Qear
T e m p e r a t " r e & n o m a l ( C -
0!2 m" Trend # $0!78%'decade0!4 m" Trend # $0!7%'decade
0!8 m" Trend # $0!65%'decade
1!6 m" Trend # $0!55%'decade
3!2 m" Trend # $0!66%'decade
@"ssian Permafrost Temperat"re Trends@"ssian Permafrost Temperat"re Trends
=ra"enfeld et al2 78++9#hang et al2 78++.9
@ i & ti $ T d@ i & ti $ T d
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@"ssian &ctive $aer Trends@"ssian &ctive $aer Trends
/+2A
/+28
/+20
+
+20
+28
+2A
0*.. 0*+ 0*. 0*+ 0*. 0*3+ 0*3. 0**+ 0**. 8+++
Qear
& c t i v e $ a e r D e p t h
& n o m a l ( m - 0*+R0**3 Change> E8. cm
=ra"enfeld et al2 78++9#hang et al2 78++.9
T li: D l tT li: D l t
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Tali: DevelopmentTali: Development
Seasonally
frozen
ground
Talik
Permafrost
; Talik > Unfro
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Permafrost CarbonPermafrost Carbon
; 08 't C in permafrost08 't C in permafrost77Tarnocai et al.Tarnocai et al., 8++*9, 8++*9
; .+ 't C in atmosphere.+ 't C in atmosphere
@oots, Siberia 7 Zimov et al 2, 8++9
H"m"s, Siberia 7 Davis, 8+++9%ammoth, Siberia
P ! ti f P f t D d tiPro!ections of Permafrost Degradation
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Pro!ections of Permafrost DegradationPro!ections of Permafrost Degradation
; 'eneral Pattern> lose area from the so"th,'eneral Pattern> lose area from the so"th,
increase active laer thic:ness everwhereincrease active laer thic:ness everwhere
Source
5eduction in
Permafrost Area
by 2/00 8;
Bncrease in
Active ayer
6"ickness 8cm;
Schaefer et al 2 78+0+9 0*/83
Zhang et al 2 78++39 0/0* A+/3+
Saito et al 2 78++9 + 0++/A++
awrence an! Slater 78++.9 *+ .++
awrence et al 2 78++39 *+ .++
= db : t &t h=eedbac:s to &tmosphere
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=eedbac:s to &tmosphere=eedbac:s to &tmosphere
; 5nerg balance5nerg balance; Snow &lbedo =eedbac: Snow &lbedo =eedbac:
; Fegetation &lbedo =eedbac: Fegetation &lbedo =eedbac:
;
Sea Ice $oss and &rctic &mplificationSea Ice $oss and &rctic &mplification; Gowen ratio seasonalitGowen ratio seasonalit
; Trace 'as =eedbac:sTrace 'as =eedbac:s; CBCB88 =ertili
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Net 5cosstem 56change (N55- Net 5cosstem 56change (N55-
; N55 1 + means net carbon "pta:e
N55 L @espiration / Photosnthesis
5nhanced bPermafrost
Carbon
=eedbac:
5nhanced b CB8
=ertili
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.3J0* 't C b 88++ is a lot of carbon.3J0* 't C b 88++ is a lot of carbon
; A2. of permafrost carbonA2. of permafrost carbon
; 8J* ppm8J* ppm increase comparableincrease comparable
Fosto: Ice Core (3+ ppm-Fosto: Ice Core (3+ ppm-
; 0A/8 of global land sin: 0A/8 of global land sin:
; J0 of fossil f"el emissionsJ0 of fossil f"el emissions
for ++ ppm targetfor ++ ppm target
Wal:ing Points on PermafrostWal:ing Points on Permafrost
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Wal:ing Points on PermafrostWal:ing Points on Permafrost
; =ree
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When is the Permafrost Carbon
Tipping Point?
Kevin Schaefer ", Ting#$n Zhang " ,
ori Br$hwiler % , &n!rew P. Barrett "
0 National Snow and Ice Data Center, Universit of Colorado8
NB&& 5arth Sstem @esearch $aborator
Bbserved Permafrost
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Bbserved Permafrost
@oc: Circle =ormation
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@oc: Circle =ormation
56pand o"t in winter when fro
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Permafrost &rea b Co"ntr
Permafrost Class b Co"ntr
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Permafrost Class b Co"ntr
Seasonall =ro
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=ariations of area e&tent of seasonally fro#en
%round and snow in t"e ort"ern 4emis!"ere
durin% t"e winter of /--DE--(
Seasonall =ro
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.ont"ly ma&imum area
e&tent of seasonally fro#en
%round
Seasonally fro#en %round
is FG & /0G km2 or GD of
t"e land area in t"eort"ern 4emis!"ere(
Seasonall =ro
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ClimateEeat"er
>eot"ermal
"eat flu&
>round
tem!erature re%ime
6"ermal diffusion
eHuation
Soil t"ermal
!ro!erties
1I 14 1 J 0
Soil moisture
conditions
Sites!ecific factors
8albedo) rou%"ness)slo!e) as!ect) snow)
soil te&ture) etc(;
& Permafrost %odel
%odeling Permafrost
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Snow
Atmos!"ere
ower +oundary
ro#en
%round
Permafrost or
unfro#en %round
6"awed
%round
.ovin% !"ase !lane: heat cond"ction
with or witho"t phase change
.ovin% !"ase !lane
Heat cond"ction
Snowsoil interface: "eat cond"ction with
or witho"t phase change
k = k s( )
hs(t) = (x,t)
C= C Fr (x,T)
k = k Fr (x, T)
C= C Fr (x,T)
T(Z fr ) = T f
k = k Th (x, T)
C = C Th(x,T)
T(Z th ) = T f
.ovin% boundary> heatcond"ction in deforming medi"m
+oundary condition: Prescribed temperat"re, orheat fl"6, or s"rface energ balance
+oundary condition: !rescribed
temperat"re or heat fl"6
%odeling Permafrost
P f t l ifi tiP f t l ifi ti
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Permafrost classificationPermafrost classification
; +y area covera%e+y area covera%e; Continuous 8K-0 of area;Continuous 8K-0 of area;; $iscontinuous 80-0 of area;$iscontinuous 80-0 of area;; S!oradic 8/00 of area;S!oradic 8/00 of area;; Bsolated 8L/0 of area;Bsolated 8L/0 of area;
; +y ocation:+y ocation:; 6errestrial6errestrial; SubiceSubice; SubseaSubsea;
5elic5elic; +y Cou!lin% wit" climate:+y Cou!lin% wit" climate:
; round $ata Products
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ro#en >round $ata Productsro#en >round $ata Products
; http>nsidc2orgfgdc
; &rctic 5&S5/'rid =ree
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Permafrost .onitorin%Permafrost .onitorin%
Permafrost Carbon in SiGC&S&
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Permafrost Carbon in SiGC&S&
Dthreshol! ' 0*A/8++0 ma6im"m active laer depth
Dactive ' active laer depth
Slow (3+-
%etabolic(.-
Str"ct"ral
(0.-
Soil Carbon Pools
Dthreshol!
Permafrost
Carbon Pool
Dactive
Dthreshol!
Dactive
Thawed Carbon
Permafrost
Carbon Pool
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