The COP21 agreement and relevant scenarios for simulating changes in climate extremes

Claudia Tebaldi, NCAR

Acknowledging the contribution of ScenarioMIP SSC members, and in particular Brian O’Neill and Ben Sanderson (NCAR)

Outline

• The backbones of emission scenarios: Shared Socio-economic Pathways (SSPs)

• The new emission scenarios: the CMIP6-approved ScenarioMIP design, in particular the new “low-warming” scenarios.

• Matching Climate model output and SSPs information to perform impact/exposure/vulnerability analyses

Scenarios dominate climate change analysis

Alternative visions of how future may evolve

Rationale:

Deep uncertainty

Facilitate integrated research and assessment

1990

1992

2014

“Shared

Socioeconomic

Pathways”

2000

The Parallel Process

Atmospheric

concentrations

“Shared

Socioeconomic

Pathways” (SSPs)

Climate

change

O’Neill & Schweizer, 2011; based on Moss et al., 2010.

Shared Socioeconomic Pathway (SSP) Logic

Socio-economic challenges

for adaptation

So

cio

-ec

on

om

ic

ch

alle

ng

es

for

mitig

atio

n

SSP 1: (Low Challenges)

SSP 3: (High Challenges)

SSP 4: (Adapt. Challenges Dominate)

SSP 5: (Mit. Challenges Dominate)

SSP 2: (Intermediate Challenges)

Relevant range

of uncertainty

spanned:

challenges to

adaptation,

mitigation

O’Neill et al., 2014.

Shared Socioeconomic Pathways (SSPs)

Narrative Qualitative description

of broad patterns of

development

Logic relating elements

of narrative to each

other

Quantitative

elements National:

Population

Education

Urbanization

GDP

SSP

SSP narratives, quantitative elements: 2017 special issue of Global Environmental Change.

SSP Database, hosted by IIASA.

Socio-economic

challenges

for adaptation

So

cio

-ec

on

om

ic

ch

alle

ng

es

for

mitig

atio

n

SSP 1: (Low Challenges)

Sustainability

SSP 3: (High Challenges)

Regional Rivalry

SSP 4: (Adapt. Challenges Dominate)

Inequality

SSP 5: (Mit. Challenges Dominate)

Fossil-fueled

Development SSP 2:

(Intermediate Challenges)

Middle of the Road

From concept to content

What determines challenges to mitigation and adaptation?

What do we know about the outlook for those determinants and their relationships?

SSP3: Regional Rivalry

Multi-pole Cold War

Conflict, focus on security

Barriers to trade, migration

Little investment in health,

education

Slow technological progress

Weak institutions

Slow income growth

O’Neill et al., 2015.

SSP5: Fossil-fueled development

Rise of the global middle class

Rapid technological progress

Large investments in human well

being (health, education)

Well functioning institutions

Rapid economic growth

Fossil-centered energy system

SSP Narratives

0

100

200

300

400

500

600

700

800

900

2000 2020 2040 2060 2080 2100

Po

pu

lati

on

(Mil

lio

ns)

0

500

1000

1500

2000

2500

3000

2000 2020 2040 2060 2080 2100

Po

pu

lati

on

(Mil

lio

ns)

SSP Population: Asia, Africa

India

China

Nigeria

Ethiopia

SSP3

SSP5

Based on KC and Lutz, 2015.

0

10

20

30

40

50

60

70

80

90

100

2000 2020 2040 2060 2080 2100

Urb

an P

op

ula

tio

n (%

)

0

10

20

30

40

50

60

70

80

90

100

2000 2020 2040 2060 2080 2100

Urb

an P

op

ula

tio

n (%

)SSP Urbanization: Asia, Africa

China

India

Nigeria

Ethiopia

Based on Jiang and O’Neill, 2015.

SSP3

SSP5

0

20

40

60

80

100

120

140

160

2000 2020 2040 2060 2080 2100

GD

P p

er

cap

(k$

/pe

rs)

SSP per capita GDP: Asia, Africa

0

20

40

60

80

100

120

140

160

2000 2020 2040 2060 2080 2100

GD

P p

er

cap

(k$

/pe

rs)

China

India

Nigeria

Ethiopia

Based on Dellink et al., 2015.

SSP3

SSP5

SSP Extensions: Regional

IMPRESSIONS: Europe

+ subnational case

studies

AACA: Adaptation

Actions for a Changing

Arctic

Absar &

Preston:

Southeast US

AgMIP:

Sub-Saharan Africa AgMIP:

South Asia

CCAFS:

E/W Africa CCAFS:

S/SE Asia

CCAFS:

C. America

SSP Extensions: Spatial population

Jones and O’Neill, 2016.

Global (Jones & O’Neill, 2016)

Coastal (Merkens et al., 2016)

Africa (Boke-Olen et al.,2017)

Europe (Terama et al., subm.)

SSP Extensions: Subnational income distribution

2030, 92 countries (Hallegatte & Rozenberg, 2017)

Global (van der Mensbrugghe,

2016)

IIASA

Vietnam

Population + structural

change, 2030

Population change

SSP5, 2030

Initial

distribution, 2000

Hallegatte & Rozenberg, 2017

Applications: Baseline emissions scenarios

SSP X

SSPs Energy & Land use Emissions

2000 2020 2040 2060 2080 2100

Ra

dia

tive

Fo

rcin

g (

W/m

2)

0

2

4

6

8

10

Radiative Forcing

RCP 4.5

SSP1

SSP2

SSP3

SSP4

SSP5

IAMs AIM

GCAM

IMAGE

MESSAGE-

GLOBIOM

ReMIND-

MAGPIE

WITCH

SSP-based IAM scenarios: 2017 special issue of Global Environmental Change.

SSP Database, hosted by IIASA.

Riahi et al., 2016.

2000 2020 2040 2060 2080 2100

Ra

dia

tive

Fo

rcin

g (

W/m

2)

0

2

4

6

8

10

Radiative Forcing

Baseline

6.0 W/m2

4.5 W/m2

2.6 W/m2

1.9 W/m2

Applications: Mitigation scenarios

SSP X

SSPs Energy & Land use Emissions

IAMs

AIM

GCAM

IMAGE

MESSAGE- GLOBIOM

ReMIND-

MAGPIE

WITCH

Riahi et al., 2016.

SSP-based IAM scenarios: 2017 special issue of Global Environmental Change. SSP Database, hosted by IIASA.

Applications: Climate projections (CMIP6)

1960 1980 2000 2020 2040 2060 2080 2100

De

gre

e C

0

1

2

3

4

5

6Temperature change

SSP5-8.5 (Baseline)

SSP3-7.0(Baseline)

SSP4-6.0

SSP5-3.4-OS

SSP1-2.6

SSP1-1.9

SSP4-3.4

RCP 2.6

1960 1980 2000 2020 2040 2060 2080 2100

W/m

2

0

1

2

3

4

5

6

7

8

9

10Total Anthropogenic Radiative Forcing

SSP5-8.5(Baseline)

SSP3-7.0(Baseline)

SSP4-6.0

SSP2-4.5

SSP5-3.4-OS

SSP1-2.6

SSP1-1.9

SSP4-3.4

RCP 4.5

1960 1980 2000 2020 2040 2060 2080 2100

CO

2 to

tal (G

t C

O2

)

-40

-20

0

20

40

60

80

100

120

140

SSP5-8.5 (Baseline)

SSP3-7.0 (Baseline)

SSP4-6.0

SSP2-4.5

SSP5-3.4-OS

SSP1-2.6

SSP4-3.4SSP1-1.9

CO2 emissions

RCP 4.5

1960 1980 2000 2020 2040 2060 2080 2100

Co

nce

ntr

atio

n C

O2

(pp

m)

300

400

500

600

700

800

900

1000

1100

1200

1300CO2 concentration

SSP5-8.5 (Baseline)

SSP3-7.0 (Baseline)

SSP4-6.0

SSP2-4.5

SSP5-3.4-OS

SSP1-2.6SSP1-1.9

SSP4-3.4

RCP 4.5

Source: Riahi et al, 2016

SSP2-4.5

1960 1980 2000 2020 2040 2060 2080 2100

De

gre

e C

0

1

2

3

4

5

6Temperature change

SSP5-8.5 (Baseline)

SSP3-7.0(Baseline)

SSP4-6.0

SSP5-3.4-OS

SSP1-2.6

SSP1-1.9

SSP4-3.4

RCP 2.6

1960 1980 2000 2020 2040 2060 2080 2100

W/m

2

0

1

2

3

4

5

6

7

8

9

10Total Anthropogenic Radiative Forcing

SSP5-8.5(Baseline)

SSP3-7.0(Baseline)

SSP4-6.0

SSP2-4.5

SSP5-3.4-OS

SSP1-2.6

SSP1-1.9

SSP4-3.4

RCP 4.5

1960 1980 2000 2020 2040 2060 2080 2100

CO

2 to

tal (G

t C

O2

)

-40

-20

0

20

40

60

80

100

120

140

SSP5-8.5 (Baseline)

SSP3-7.0 (Baseline)

SSP4-6.0

SSP2-4.5

SSP5-3.4-OS

SSP1-2.6

SSP4-3.4SSP1-1.9

CO2 emissions

RCP 4.5

1960 1980 2000 2020 2040 2060 2080 2100

Co

nce

ntr

atio

n C

O2

(pp

m)

300

400

500

600

700

800

900

1000

1100

1200

1300CO2 concentration

SSP5-8.5 (Baseline)

SSP3-7.0 (Baseline)

SSP4-6.0

SSP2-4.5

SSP5-3.4-OS

SSP1-2.6SSP1-1.9

SSP4-3.4

RCP 4.5

Source: Riahi et al, 2016

SSP2-4.5

Ra

dia

tive

Fo

rcin

g (

W/m

2) ESMs

“ScenarioMIP”

Climate

Projections

Selected

SSP-based

marker

scenarios

2100 forcing level

(W/m2)

8.5

6.0

4.5

2.6

SSP1 Sustainability

SSP2 Middle of the Road

SSP3 Regional Rivalry

SSP4 Inequality

SSP5 Fossil-fueled

Development

Previous

Scenarios (CMIP5 RCPs)

Tier 1 Ens: Initial condition ensemble

LTE: Long-term extension

OS: Overshoot

7.0

3.4

1.9

1

Tier 2

OS

+LTE

+LTE

+Ens

+LTE

ScenarioMIP Design Summary (O’Neill et al., 2016, GMD)

PRELIMINARY DRAFT

1960 1980 2000 2020 2040 2060 2080 2100

CO

2 to

tal (

Gt C

O2)

-40

-20

0

20

40

60

80

100

120

140

SSP5-8.5 (Baseline)

SSP3-7.0 (Baseline)

SSP4-6.0

SSP2-4.5

SSP5-3.4-OS

SSP1-2.0SSP1-2.6

SSP4-3.4

RCP 4.5

1960 1980 2000 2020 2040 2060 2080 2100

Con

cent

ratio

n C

O2

(ppm

)

300

400

500

600

700

800

900

1000

1100

1200

1300

SSP5-8.5 (Baseline)

SSP3-7.0 (Baseline)

SSP4-6.0

SSP2-4.5

SSP5-3.4-OS

SSP1-2.6SSP1-2.0

SSP4-3.4

RCP 4.5

1960 1980 2000 2020 2040 2060 2080 2100

W/m

2

0

1

2

3

4

5

6

7

8

9

10

SSP5-8.5(Baseline)

SSP3-7.0(Baseline)

SSP4-6.0

SSP2-4.5

SSP5-3.4-OS

SSP1-2.6

SSP1-2.0

SSP4-3.4

RCP 4.5

1960 1980 2000 2020 2040 2060 2080 2100

Deg

ree

C

0

1

2

3

4

5

6

SSP5-8.5 (Baseline)

SSP3-7.0(Baseline)

SSP4-6.0

SSP2-4.5

SSP5-3.4-OS

SSP1-2.6

SSP1-2.0

SSP4-3.4

RCP 2.6

Total Radiative Forcing Temperature change

CO2 concentrationCO2 emissions

Source: Riahi et al, 2016Cour tes y o f K .R iah i

SSP5-8.5

SSP3-7.0

SSP2-4.5

SSP1-2.6

One run per scenario

2016-2100

SSP1-1.9

SSP4-6.0

SSP4-3.7

9 more IC ensemble

members for SSP3-7.0

Overshoot

Long-term extensions

ScenarioMIP Design Summary

Tier1 Tier 2

While we wait (at least until the end of 2018, maybe longer)

CESM1-CAM5 10-members IC ensembles are available under three

low-warming scenarios:

1.5C not exceed

2.0C

1.5C overshoot

Documented here: Community Climate Simulations to assess

avoided impacts in 1.5C and 2C futures, Benjamin M. Sanderson et

al. ESD, esd-2017-42.

Downloadable from the Earth System Grid website.

While we wait (at least until the end of 2018, maybe longer)

CESM1-CAM5 10-members IC ensembles are available under three low-warming scenarios:

1.5C not exceed

2.0C

1.5C overshoot

Documented here: Community Climate Simulations to assess avoided impacts in 1.5C and

2C futures, Benjamin M. Sanderson et al. ESD, esd-2017-42.

Downloadable from the Earth System Grid website.

An example of matching climate model output to SSP information:

Population exposure to heatwave days (Jones et al., forthcoming)

person-days

An example of matching climate model output to SSP information:

Population exposure to heatwave days (Jones et al., forthcoming)

person-days