Arctic climate

(1)

Helge Drange University of Bergen Valérie Masson-Delmotte

LSCE (CEA-CNRS-UVSQ/IPSL)

Arctic climate

In Northern Mists, by Fridtjof Nansen (1911)

Valérie Masson-Delmotte

LSCE (CEA-CNRS-UVSQ/IPSL), Gif-sur-Yvette, France

Helge Drange

Univ. of Bergen and the Bjerknes Centre, Norway

(2)

Observed temperature

(1880-2014)

and Arctic sea ice

(1953-2014)

(3)

Temperature animation here

(4)

(5)

Polar amplification

(6)

E xt en t (1 0 6 k m 2 )

Extent of Arctic sea ice, September

Reduced with more than ⅓ since 1978, halved since the 1950s

http://nsidc.org/data and http://www.metoffice.gov.uk/hadobs

Satellite 2014

Reconstructed

(7)

E xt en t (1 0 6 k m 2 )

Extent of Arctic sea ice, September

Reduced with more than ⅓ since 1978, halved since the 1950s

http://nsidc.org/data and http://www.metoffice.gov.uk/hadobs

Satellite 2014

Reconstructed

(8)

Mean ice cover,

September 2012

(9)

−1.0 1.0 1.7 2.4 3.0

Modelled change in Arctic surface

temperature

(1979-2012)

Global temperature: +0.6 °C

Bader (2014), Ding et al. (2014)

(10)

−1.0 1.0 1.7 2.4 3.0

Central questions:

How unusual?

Naturally occurring variations?

Degree of human influence?

What about the future?

Bader (2014), Ding et al. (2014)

(11)

From a

paleoclimatologist’s

point of view…

(12)

(i) How unusual are these recent changes?

Toolbox: proxy records

from natural archives

(13)

• Arctic warming, and sea ice retreat unprecedented in more than 1400 years

• Similar conclusions for sea level rise and global warming

Temperature change (°C) ^Year

PAGES2k, 2013

(ii) How unusual are these

recent changes?

(14)

1800 ppb 400 ppm

Atmospheric composition

EPICA and Vostok ice core data

(iii) How unusual are these

recent changes?

(15)

• Past sustained polar warming over thousands of years has led to deglaciation of ice sheets and sea level rise by several meters

• Threshold for Greenland ice sheet deglaciation between 1 and 4°C global warming above pre-industrial level

IPCC AR5, Climatechange2013.org

(iv) How unusual are these

recent changes?

(16)

From a climate

modellers' point of

view…

(17)

Equation of motion

Conservation water vapour

Conservation heat Radiation/clouds/

Particles/etc.

A tm o sp h e re

Water budget Snow and ice

budget

Heat budget

La n d

Surface friction Exchange

of heat Exchange

of water

After Manabe & Stouffer (2000)

Conservation of salt

Equations for motion and growth/melting sea

ice

Conservation

of heat ^Equation

of motion

O ce an & se a ic e

Runof

+ Human-made greenhouse gases and aerosol particles

(18)

Equation of motion

Conservation water vapour

Conservation heat Radiation/clouds/

Particles/etc.

A tm o sp h e re

Water budget Snow and ice

budget

Heat budget

La n d

Surface friction Exchange

of heat Exchange

of water

After Manabe & Stouffer (2000)

Conservation of salt

Equations for motion and growth/melting sea

ice

Conservation

of heat ^Equation

of motion

O ce an & se a ic e

Runof

(19)

Possible future

uncertainty ≠ no certainty

(20)

Helge Drange Geofysisk institutt Universitetet i Bergen

20 06

G lo b al p o p u la ti o n ( b ill io n ) G lo b al C O 2 -e m is si o n s ( G t- C /y r)

(21)

20 06

G lo b al p o p u la ti o n ( b ill io n ) G lo b al C O 2 -e m is si o n s ( G t- C /y r)

(22)

20 06

G lo b al p o p u la ti o n ( b ill io n ) G lo b al C O 2 -e m is si o n s ( G t- C /y r)

(23)

20 06

RCP8.5

RCP6.0

RCP4.5 RCP2.6

G lo b al p o p u la ti o n ( b ill io n ) G lo b al C O 2 -e m is si o n s ( G t- C /y r)

(24)

20 06

RCP8.5

RCP6.0

RCP4.5 RCP2.6

G lo b al p o p u la ti o n ( b ill io n ) G lo b al C O 2 -e m is si o n s ( G t- C /y r) ₂ ⁰¹

4

(25)

20 06

RCP8.5

RCP6.0

RCP4.5 RCP2.6

G lo b al p o p u la ti o n ( b ill io n ) G lo b al C O 2 -e m is si o n s ( G t- C /y r) ₂ ⁰¹

4

(26)

Modelled change in annual mean temperature, Arctic

(2081-2100 relative to 1986-2005)

RCP8.5 RCP2.6

+9 to +11 °C

+2 to +3 °C

• Arctic amplification occurred during the past and is expected in the future

• Climate models are tested against past climate data

• Global warming by more than 2°C would be outside of the range of variations of the past million years

• For comparison, modern woman and man has been on

Earth for some 200.000 years

(27)

Modelled change in annual mean precipitation, Arctic

(2081-2100 relative to 1986-2005)

RCP8.5 RCP2.6

~ 50 % ~ 10 %

(28)

Modelled change in heavy (>97,5 %) precipitation

(2081-2100 relative to 1986-2005)

RCP8.5 RCP2.6

30-50 %

> 50 %

• Approaching unknown territory for ecosystems and

societies

(29)

E xt en t (1 0 6 k m 2 )

Arctic sea ice in September, 1900-2100

Observed 1953-2014 | Model simulations 1900-2100

Virtually no sea ice

Stroeve et al. (2012), updated

Large differences between the scenarios (solid lines)

Large model uncertainty (shadings)

(30)

Defference Models – Obs

NB: Poorly modelled sea ice thickness (Sep)

Multi-model mean

Stroeve, NSIDC

Observed

(ICESat)

(31)

Future sea level change

• For the next decades, dominant role of ocean warming and glacier retreat

• For the long term, key uncertainty associated with the response of the Greenland and Antarctic ice sheet

• Large warming would lead to up to

1 m sea level rise in 2100, 3 m by

2300

(32)

Concluding remarks

 For the Arctic, amplifying mechanisms acting at the regional scale but also at the global scale

 Arctic climate change leads to a complex mixture of opportunities and vulnerabilities

 Risks of irreversible loss: biodiversity, cultural heritages

 Thawing of the vast permafrost regions in the Arctic is ongoing, with poorly known climate implications

 Based on current understanding, rapidly reduced

greenhouse gas emissions will strongly limit climate

changes in the Arctic

Arctic climate

Arctic climate

In Northern Mists, by Fridtjof Nansen (1911)

Valérie Masson-Delmotte

LSCE (CEA-CNRS-UVSQ/IPSL), Gif-sur-Yvette, France

Helge Drange

Univ. of Bergen and the Bjerknes Centre, Norway

Observed temperature

(1880-2014)

and Arctic sea ice

(1953-2014)

Temperature animation here

Polar amplification

E xt en t (1 0 6 k m 2 )

Extent of Arctic sea ice, September

Reduced with more than ⅓ since 1978, halved since the 1950s

http://nsidc.org/data and http://www.metoffice.gov.uk/hadobs

Satellite 2014

Reconstructed

E xt en t (1 0 6 k m 2 )

Extent of Arctic sea ice, September

Reduced with more than ⅓ since 1978, halved since the 1950s

http://nsidc.org/data and http://www.metoffice.gov.uk/hadobs

Satellite 2014

Reconstructed

Mean ice cover,

September 2012

−1.0 1.0 1.7 2.4 3.0

Modelled change in Arctic surface

temperature

(1979-2012)

Global temperature: +0.6 °C

−1.0 1.0 1.7 2.4 3.0

Central questions:

How unusual?

Naturally occurring variations?

Degree of human influence?

What about the future?

From a

paleoclimatologist’s

point of view…

(i) How unusual are these recent changes?

Toolbox: proxy records

from natural archives

• Arctic warming, and sea ice retreat unprecedented in more than 1400 years

• Similar conclusions for sea level rise and global warming

Temperature change (°C) Year

PAGES2k, 2013

(ii) How unusual are these

recent changes?

1800 ppb 400 ppm

Atmospheric composition

EPICA and Vostok ice core data

(iii) How unusual are these

recent changes?

• Past sustained polar warming over thousands of years has led to deglaciation of ice sheets and sea level rise by several meters

• Threshold for Greenland ice sheet deglaciation between 1 and 4°C global warming above pre-industrial level

IPCC AR5, Climatechange2013.org

(iv) How unusual are these

recent changes?

From a climate

modellers' point of

view…

Equation of motion

Conservation water vapour

Conservation heat Radiation/clouds/

Particles/etc.

A tm o sp h e re

Water budget Snow and ice

budget

Heat budget

La n d

Surface friction Exchange

of heat Exchange

of water

Conservation of salt

Equations for motion and growth/melting sea

ice

Conservation

of heat Equation

Temperature change (°C) ^Year

of heat ^Equation

of heat ^Equation

G lo b al p o p u la ti o n ( b ill io n ) G lo b al C O 2 -e m is si o n s ( G t- C /y r) ₂ ⁰¹

G lo b al p o p u la ti o n ( b ill io n ) G lo b al C O 2 -e m is si o n s ( G t- C /y r) ₂ ⁰¹