Sea-level contributions from glaciers

(1)

Alaska Range

Regine Hock ¹ , Ben Marzeion ² , A. Bliss ³ , R. Giesen ⁴ , Y. Hirabayashi ⁵ , M. Huss ⁶ , V. Radic ⁷ , A. Slangen ⁸

1 Geophysical Institute, University of Alaska Fairbanks, ² Bremen University, 3 Colorado State Univ., ⁴ Utrecht University, ⁵ University of Tokyo,

6 ETH Zurich, ⁷ UBC Vancouver, ⁸ Royal Netherlands Institute for Sea Research

Sea-level contributions

from glaciers

(2)

Incomplete glacier inventory

~200,000 glaciers

~705,000 km ²

(incl. glaciers outside the

ice sheets in Greenland & Antarctica)

Sea-level equivalent SLE = ~ 0.4 - 0.5 m

All glaciers outside the ice sheets

(3)

World-wide glacier retreat and mass loss

McCall Glacier

Muir Glacier

1958 2003

1941 2004

(4)

39%

27%

12%

9%

13%

Mountain glaciers (1%)

Green- land

11%

Antarctica

88%

• Glacier contribution larger than the mass loss from both ice sheets combined

Greenland Thermal

expansion

Glaciers

Antarctica

Land water storage

Ice volume Sea-level contribution

1992 - 2010, IPCC (2013)

(5)

Mass budget (Gt a

^-1

) All glaciers other than the ice sheets in Greenland and Antarctica

Glacier area

• Largest regional contributors: Arctic Canada, Alaska,

Greenland periphery, Southern Andes

• Average thinning rate = 0.4 m yr ^-1

Globa glacier mass loss = 0.71 ± 0.08 mm SLE yr -1

• ^--> 29% of observed global sea-level rise

• Roughly equivalent to ice sheet mass loss

• Global glacier mass changes 2003 - 2009

Gardner et al., 2013, Science Numbers refer to

region numbers

(6)

How to model glaciers on global scale?

Model approach Comment/Issues References

Simple extrapolations • scenarios based on recent rates

• lack of physical basis

Meier et al. 2007 Bahr et al. 2009

Mass balance sensitivities

to temp/precip change • sensitivities vary

in space and time Van de Wal & Wild, 2001 Slangen et al., 2012

Transient simulations of mass balance driven by climate

data

(T, Prec)

• downscaling climate data to local scale

Marzeion et al. 2012 Radic et al., 2013

Hirabayashi et al. 2013 Giesen & Oerlemans, 2013

Huss & Hock, 2015

(7)

Text

Surface mass balance

Frontal ablation

(calving + submarine melt)

Glacier geometry changes

Sea-level contribution Climate

data

Inventory

Input data Model component

How to model glaciers on global scale?

(8)

RCP4.5

RCP8.5

Marzeion et al.

2012, The Cryosph.

15 GCMs

Multimodel mean ± std.dev.; Emission scenarios (A1B, RCPs)

Giessen &

Oerlemans 2013

Clim.Dyn.

8 GCMs Slangen et

al 2012 Clim.Dyn.

12 GCMs

A1B

A1B A1B

A1B

Incomplete

inventory Complete inventory

200 A1B

Global projections until 2100: Model comparison

100 300

Radic et al, 2013 Clim.Dyn.

14 GCMs

Huss & Hock 2015

Frontiers 14 GCMs

RCP4.5 RCP2.8

Hirabayashi et al. 2013,

*

HRL, 10 GCMs

RCP8.5 RCP8.5

Raper &

Braithwaite,2006

*

Nature, 2 GCMs Radic &

Hock, 2011 NatGeosc.

10 GCMs

Sea-level equivalent (mm)

(9)

RCP4.5

RCP8.5

Marzeion et al.

15 GCMs

Multimodel mean ± std.dev.; Emission scenarios (A1B, RCPs)

Giessen &

Clim.Dyn.

al 2012 Clim.Dyn.

12 GCMs

A1B

A1B A1B

A1B

Incomplete

inventory Complete inventory

200 A1B

Global projections until 2100: Model comparison

100 300

14 GCMs

Huss & Hock 2015

RCP4.5 RCP2.8

*

HRL, 10 GCMs

RCP8.5 RCP8.5

Raper &

*

Nature, 2 GCMs

*excluding Greenland/Antarctic periphery

Radic &

10 GCMs

Sea-level equivalent (mm)

only 7 models in

last 15 years

(10)

Radic &

10 GCMs

RCP4.5

RCP8.5

Marzeion et al.

15 GCMs

Multimodel mean ± std.dev.; Emission scenarios (A1B, RCPs)

Giessen &

Oerleman s 2013 Clim.Dyn.

al 2012 Clim.Dyn.

12 GCMs

A1B

A1B A1B

A1B

Incomplete

inventory Complete inventory

200 Sea-level equivalent (mm)

Raper &

*

Nature, 2 GCMs

A1B

Global projections until 2100: Model comparison

100 300

14 GCMs

Huss & Hock 2015

RCP4.5 RCP2.8

Hirabayashi et al, 2013, HRL,

10 GCMs

RCP8.5 RCP8.5

• Inventoried glacierized area in World Glacier Inventory (WGI)

• NOT inventoried glacierized area by 2011

@Radic

(11)

RCP4.5

RCP8.5

Marzeion et al.

15 GCMs

Multimodel mean ± std.dev.; Emission scenarios (A1B, RCPs)

Giessen &

Oerleman s 2013 Clim.Dyn.

al 2012 Clim.Dyn.

12 GCMs

A1B

A1B A1B

A1B

Incomplete

inventory Complete inventory

200 A1B

Global projections until 2100: Model comparison

100 300

14 GCMs

Huss & Hock 2015

RCP4.5 RCP2.8

RCP8.5 RCP8.5

• Globally complete Inventory

(Randolph Glacier Inventory, RGI)

• 19 primary glacier regions

• RGI now includes area-altitude distribution of each glacier

Raper &

*

10 GCMs

Sea-level equivalent (mm)

(12)

RCP4.5

RCP8.5

Marzeion et al.

15 GCMs

Multimodel mean ± std.dev.; Emission scenarios (A1B, RCPs)

Giessen &

Clim.Dyn.

al 2012 Clim.Dyn.

12 GCMs

A1B

A1B A1B

A1B

Incomplete

inventory Complete inventory

200 A1B

Global projections until 2100: Model comparison

100 300

14 GCMs

Huss & Hock 2015

RCP4.5 RCP2.6

*

HRL, 10 GCMs

RCP8.5 RCP8.5

Raper &

*

10 GCMs

Sea-level equivalent (mm)

(13)

RCP4.5

RCP8.5

Marzeion et al.

15 GCMs

Multimodel mean ± std.dev.; Emission scenarios (A1B, RCPs)

Giessen &

Clim.Dyn.

al 2012 Clim.Dyn.

12 GCMs

A1B

A1B A1B

A1B

Incomplete

inventory Complete inventory

200 A1B

Global projections until 2100: Model comparison

100 300

14 GCMs

Huss & Hock 2015

RCP4.5 RCP2.6

*

HRL, 10 GCMs

RCP8.5 RCP8.5

Raper &

*

Nature, 2 GCMs

*excluding Greenland/Antarctic periphery

Radic &

10 GCMs

Sea-level equivalent (mm)

(14)

to provide a framework for a coordinated intercomparison of global-scale glacier mass change models

to foster model improvements and reduce uncertainties in global glacier projections and their contribution to sea level

What is GlacierMIP?

(15)

GlacierMIP

• Slangen et al. 2012

• Marzeion et al. 2012

• Bliss et al. 2014, Radic et al. 2013

• Giesen & Oerlemans 2013

• Hirabayashi et al. 2013 (HYOGA5)

• Huss & Hock 2015 (GloGEM)

• 262 model runs submitted to GlacierMIP

• ^{34 GCMs}

• 5 emission scenarios (4 RCPs, A1B)

• not all compute Antarctic/

Greenland periphery

6 participating models:

(16)

GlacierMIP

• Slangen et al. 2012

• Marzeion et al. 2012

• Bliss et al. 2014, Radic et al. 2013

• Giesen & Oerlemans 2013

• Hirabayashi et al. 2013 (HYOGA5)

• Huss & Hock 2015 (GloGEM)

6 participating models:

Calculated mass changes

of each glacier individually

(or glacier grid cell)

(17)

GlacierMIP

• Slangen et al. 2012

• Marzeion et al. 2012

• Bliss et al. 2014, Radic et al. 2013

• Giesen & Oerlemans 2013

• Hirabayashi et al. 2013 (HYOGA5)

• Huss & Hock 2015 (GloGEM)

6 participating models:

Computed 89 glaciers,

extrapolate results to

remaining glaciers

(18)

GlacierMIP

• Slangen et al. 2012

• Marzeion et al. 2012

• Bliss et al. 2014, Radic et al. 2013

• Giesen & Oerlemans 2013

• Hirabayashi et al. 2013 (HYOGA5)

• Huss & Hock 2015 (GloGEM)

6 participating models:

Sensitivity approach

(19)

-24%

-48%

-26%

-33%

V olume (normalized)

RCP2.6 RCP4.5 RCP8.5

Global volume projections 2015 - 2100

-14% -20%

Marzeion et al

Giesen&Oerlemans Huss&Hock

Bliss/Radic et al.

Slangen et al.

multi-model mean individual GCMs

RCP = Representative Concentration Pathways (emission scenarios)

(20)

Marzeion et al Giesen&Oerlemans Huss&Hock

Bliss/Radic et al.

V olume (normalized)

2100 1

2020

RCP8.5

0 1

0 0.6

multi-model mean

individual GCMs

(21)

Bliss/Radic et al.

Slangen et al.

V olume (normalized)

2100 1

2020

RCP8.5

0 1

0 0.6

multi-model mean

individual GCMs

(22)

Bliss/Radic et al.

V olume (normalized)

2100 1

2020

RCP8.5

0 1

0 0.6

multi-model mean

individual GCMs

(23)

Bliss/Radic et al.

Slangen et al.

V olume (normalized)

2100 1

2020

RCP8.5

0 1

0 0.6

multi-model mean

individual GCMs

(24)

RCP2.6 RCP4.5 RCP8.5

Volume evolution (relative to 2015)

-24%

-14% -20%

Cumulative Sea-level equivalent, SLE (cm)

Global incl. Antarctic/Greenland periphery, 2015-2100

multi-model mean individual GCMs

(mm/yr) (cm)

Bliss/Radic et al.

Slangen et al.

RCP2.6

Rate of glacier sea-level contribution (mm/yr)

22 cm

16 cm 10

9 13 15

RCP4.5 RCP8.5

(25)

How do the glacier projections differ among different glacier models ?

Alaska

NorESM1-M, RCP8.5

W. C an ad a & US

Arctc Canada N

Greenland Iceland Svalbard

New Zealand Scandinavia

Russian Arctic

North Asia

Central Europe Caucasus

Central Asia

South

Asia (W)

Low Latitudes Southern

Andes

Antarctic Global

Marzeion et al

Bliss/Radic et al.

Slangen et al.

V

olume loss (%)

Arctc Canada S South

Asia (E)

Possible causes for observed differences:

Different region boundaries Different initial volumes

Model physics Model calibration

Downscaling of climate data

GlacierMIP:

Same region boundaries Same initial volumes

Same set of GCMs/

emission scnearios

(26)

Text

Surface mass balance

Frontal ablation

Glacier geometry changes

Sea-level contribution Climate

data

Inventory

Modeling challenges: Surface mass balance

• Debris cover

Frontal ablation

(calving + submarine melt)

Input data Model component

(27)

Frontal ablation

(calving + submarine melt)

Surface mass balance

Glacier geometry changes

Sea-level contribution Climate

data

Inventory

• 38 % of all glacier area drains through tidewater glaciers

• not included in all but one published models

Modeling challenges: Frontal ablation

Input data Model component

(28)

Frontal ablation (calving and submarine melt) is approx. 10% of total ablation

Mass balance partitioning

20-yr periods between 1980 and 2100

(29)

Text

Surface mass balance

Frontal ablation

Glacier geometry changes

Sea-level contribution Climate

data

Inventory

Modeling challenges: Sea-level

Glacier tongue is not floating but grounded

Input data Model component

(30)

Text

Surface mass balance

Frontal ablation

Glacier geometry changes

Sea-level contribution Climate

data

Inventory

Modeling challenges: Sea-level

Glacier tongue is not floating but grounded

Input data Model component

(31)

Text

Surface mass balance

Frontal ablation

Glacier geometry changes

Sea-level contribution Climate

data

Inventory

Modeling challenges: Sea-level

Glacier tongue is not floating but grounded

Input data Model component

(32)

Text

Surface mass balance

Frontal ablation

Glacier geometry changes

Sea-level contribution Climate

data

Inventory

Modeling challenges: Sea-level

Glacier Sea level

Ocean Ice below

sea level

10-12% reduction in SLE

(Huss & Hock, 2015)

Glacier tongue is not floating but grounded

Icebergs

Input data Model component

(33)

Text

Surface mass balance

Frontal ablation

Glacier geometry changes

Sea-level contribution Climate

data

Inventory

Endorheic basins ???

Modeling challenges: Sea-level

Input data Model component

(34)

Sea-level contributions from glaciers

Regine Hock 1 , Ben Marzeion 2 , A. Bliss 3 , R. Giesen 4 , Y. Hirabayashi 5 , M. Huss 6 , V. Radic 7 , A. Slangen 8

1 Geophysical Institute, University of Alaska Fairbanks, 2 Bremen University, 3 Colorado State Univ., 4 Utrecht University, 5 University of Tokyo,

6 ETH Zurich, 7 UBC Vancouver, 8 Royal Netherlands Institute for Sea Research

Sea-level contributions

from glaciers

Incomplete glacier inventory

~200,000 glaciers

~705,000 km 2

(incl. glaciers outside the

ice sheets in Greenland & Antarctica)

Sea-level equivalent SLE = ~ 0.4 - 0.5 m

All glaciers outside the ice sheets

World-wide glacier retreat and mass loss

McCall Glacier

Muir Glacier

1958 2003

1941 2004

39%

27%

12%

9%

13%

Mountain glaciers (1%)

Green- land

11%

Antarctica

88%

• Glacier contribution larger than the mass loss from both ice sheets combined

Greenland Thermal

expansion

Glaciers

Antarctica

Land water storage

Ice volume Sea-level contribution

1992 - 2010, IPCC (2013)

Mass budget (Gt a

) All glaciers other than the ice sheets in Greenland and Antarctica

Glacier area

• Largest regional contributors: Arctic Canada, Alaska,

Greenland periphery, Southern Andes

• Average thinning rate = 0.4 m yr -1

Globa glacier mass loss = 0.71 ± 0.08 mm SLE yr -1

• --> 29% of observed global sea-level rise

• Roughly equivalent to ice sheet mass loss

•

Global glacier mass changes 2003 - 2009

How to model glaciers on global scale?

Model approach Comment/Issues References

Simple extrapolations • scenarios based on recent rates

• lack of physical basis

Meier et al. 2007 Bahr et al. 2009

Mass balance sensitivities

to temp/precip change • sensitivities vary

in space and time Van de Wal & Wild, 2001 Slangen et al., 2012

Transient simulations of mass balance driven by climate

data

(T, Prec)

• downscaling climate data to local scale

Marzeion et al. 2012 Radic et al., 2013

Hirabayashi et al. 2013 Giesen & Oerlemans, 2013

Huss & Hock, 2015

Text

Surface mass balance

Frontal ablation

(calving + submarine melt)

Glacier geometry changes

Sea-level contribution Climate

data

Inventory

Input data Model component

How to model glaciers on global scale?

RCP4.5

RCP8.5

Multimodel mean ± std.dev.; Emission scenarios (A1B, RCPs)

A1B

A1B A1B

A1B

Incomplete

inventory Complete inventory

Regine Hock ¹ , Ben Marzeion ² , A. Bliss ³ , R. Giesen ⁴ , Y. Hirabayashi ⁵ , M. Huss ⁶ , V. Radic ⁷ , A. Slangen ⁸

1 Geophysical Institute, University of Alaska Fairbanks, ² Bremen University, 3 Colorado State Univ., ⁴ Utrecht University, ⁵ University of Tokyo,

6 ETH Zurich, ⁷ UBC Vancouver, ⁸ Royal Netherlands Institute for Sea Research

~705,000 km ²

• Average thinning rate = 0.4 m yr ^-1

• ^--> 29% of observed global sea-level rise