Twila Moon

National Snow and Ice Data Center

Cooperative Institute for Research cin Environmental Systems

University of Colorado - Boulder

twila.science@gmail.com - www.changingice.com - @twilamoon

Land Ice: Observations and updates from the front lines

[Image: NASA Earth Observatory]

Land ice reaches pole to pole

Losing ice globally

[ESA, adapted from Zemp et al., Nature, 2019]

Gr. Ice Sheet

2000-2016

-3700 Gt

Ant. Ice Sheet

2000-2016

-1900 Gt

Losing ice globally

[ESA, adapted from Zemp et al., Nature, 2019]

Local to global impacts

Local to global impacts

6 m 60 m

Local to global impacts

7

Combined

Heat

Ice

Rate = 3.2 ± 0.4 mm/year

Increasing by ~0.1 mm/year, each year

[Leuliette, 2018; NOAA Laboratory for Satellite Altimetry]

Sea Level Rise Today (1993-2018)

[modified from Chen et al., Nature Climate Change, 2017]

Greenland

Antarctica

Land H2O storage

Glaciers & ice caps

Ocean heat

Growing influence of land ice (Greenland!)

Forecast for ocean heat and glacier loss

[Kopp et al., Earth’s Future, 2014]

Thermal expansion Glaciers & Ice caps

Relatively well-constrained Narrow potential range

Greenland Antarctica

Wide range of possible contributions

Increased

snowfall dominates

Runaway ice

sheet decline

Forecast for Earth’s ice sheets

[Kopp et al., Earth’s Future, 2014]

Uncertainty: Marine Ice-Cliff Instability

Helheim Glacier,Greenland

An example??

[DeConto and Pollard, Nature, 2016]

[DeConto and Pollard, Nature, 2016]

Uncertainty: Marine Ice-Cliff Instability

Helheim Glacier,Greenland

An example??

[Edwards et al., Nature, 2019]

Uncertainty: Marine Ice-Cliff InstabilityA

nta

rcti

cco

ntr

ibu

tio

n

[Thomas and Bentley, Quarter. Res., 1978; Image: Hanna et al., Nature, 2013]

Uncertainty: Marine Ice Sheet Instability

Uncertainty: Marine Ice Sheet Instability

[Thomas and Bentley, Quarter. Res., 1978; Image: Hanna et al., Nature, 2013]

Uncertainty: Marine Ice Sheet Instability

[Thomas and Bentley, Quarter. Res., 1978; Image: Hanna et al., Nature, 2013]

Uncertainty: Marine Ice Sheet Instability

[Morlighem: BedMachine Antarctica]

Uncertainty: Marine Ice Sheet Instability

[Morlighem: BedMachine Antarctica]

[Figure: Joughin et al., Science, 2014; Additional results - Rignot et al., GRL, 2014]

MISI: Thwaites Glacier

Neighbor in steady state Strong meltMedium melt,

weak ice shelf margins

Sea level rise due to ice lossfrom Greenland Ice Sheetunder RCP8.5, mm/year

[Horton et al., Ann Rev Env Resour, 2018]

mm/year (2006 – 2100)

Sea level rise will not be evenly distributed

Sea level rise due to ice lossfrom Antarcticaunder RCP8.5, mm/year

[Horton et al., Ann Rev Env Resour, 2018]

mm/year (2006 – 2100)

Sea level rise will not be evenly distributed

[Larour et al., Science Advances, 2017]

Local SLR depends on local ice loss

Interest from planners & decision makers

• NSF Coastlines and People initiative

[Image: Times Record online]

Interest from planners & decision makers

• NSF Coastlines and People initiative

• House Subcommittee on the Environment hearing (House Science, Space and Technology Committee subcommittee) - Sea Change: Impacts of Climate Change on Our Oceans and Coasts (Feb. 2019)

[Image: Times Record online]

Interest from planners & decision makers

• NSF Coastlines and People initiative

• House Subcommittee on the Environment hearing (House Science, Space and Technology Committee subcommittee) - Sea Change: Impacts of Climate Change on Our Oceans and Coasts (Feb. 2019)

• National Academies considering activities

[Image: Times Record online]

Interest from planners & decision makers

• NSF Coastlines and People initiative

• House Subcommittee on the Environment hearing (House Science, Space and Technology Committee subcommittee) - Sea Change: Impacts of Climate Change on Our Oceans and Coasts (Feb. 2019)

• National Academies considering activities

• Conferences: SLR, Managed Retreat, Coastal Resilience & Adaptation

[Image: Times Record online]

[Mouginot et al., PNAS, 2019]

[Mouginot et al., PNAS, 2019]

SMB: -1±16 Gt/yrD: -49±9 Gt/yr

1980-1990

[Mouginot et al., PNAS, 2019]

SMB: -1±16 Gt/yrD: -49±9 Gt/yr

1980-1990

SMB: +0±16 Gt/yrD: -40±8 Gt/yr

1990-2000

[Mouginot et al., PNAS, 2019]

SMB: -1±16 Gt/yrD: -49±9 Gt/yr

1980-1990

SMB: +0±16 Gt/yrD: -40±8 Gt/yr

1990-2000

SMB: -98±16 Gt/yrD: -87±8 Gt/yr

2000-2010

[Mouginot et al., PNAS, 2019]

SMB: -1±16 Gt/yrD: -49±9 Gt/yr

1980-1990

SMB: +0±16 Gt/yrD: -40±8 Gt/yr

1990-2000

SMB: -98±16 Gt/yrD: -87±8 Gt/yr

2000-2010

[Mouginot et al., PNAS, 2019]

SMB: -1±16 Gt/yrD: -49±9 Gt/yr

1980-1990

SMB: +0±16 Gt/yrD: -40±8 Gt/yr

1990-2000

SMB: -98±16 Gt/yrD: -87±8 Gt/yr

2000-2010

[Image: Twila Moon]

Important ice-ocean interactions

RCP4.5 without melt coupling

2000 2050 2100

Coupled models change results

[Golledge et al., Nature, 2019]

RCP4.5 without melt coupling with melt coupling

2000 2050 2100 2000 2050 2100

Coupled models change results

[Golledge et al., Nature, 2019]

RCP4.5 without melt coupling with melt coupling

2000 2050 2100 2000 2050 2100RCP8.5

Coupled models change results

[Golledge et al., Nature, 2019]

RCP4.5 without melt coupling with melt coupling

2000 2050 2100 2000 2050 2100RCP8.5

Coupled models change results

[Golledge et al., Nature, 2019]

[Larour et al., Science, 2019]

2000 surface

Bedrock

Coupled models change results

[Larour et al., Science, 2019]

Bedrock

Ocean

2350 surface: Uncoupled

Coupled models change results

[Larour et al., Science, 2019]

Bedrock

Ocean

2350 surface: Coupled

Coupled models change results

[Roberts et al., 2010]

Glacier geoengineering

[Moore et al., Nature comment, 2018]

Glacier geoengineering

…

[Moon et al., Nature correspondence, 2018]

[Moore et al., Nature comment, 2018]

Climate geoengineering

Clark et al. 2016

How much carbon we emit over the next 100 years.

Land ice loss is ~irreversible,with millennial-scale impact

[Clark et al. 2016]

Ice loss is ~irreversible,with millennial-scale impact

Thank you!