what would be the impacts of climate change … · what would be the impacts of climate change...

WHAT WOULD BE THE IMPACTS OF CLIMATE CHANGE ASSUMING NO, OR SOME, OR MUCH EMISSIONS CONTROL AND SEQUESTRATION?

Martin parryCo-Chair, Working Group II,

IPCC

Global mean temperature predictions

Ensembles of four predictions of global mean temperature resulting from ‘business as usual’ changes in greenhouse gases following on from observed changes since 1860 (orange curves). The addition of sulphate aerosol cooling is shown in the red curves.

Tem

pera

ture

(°C

)

Year

13

14

15

16

17

18

1860 1880 1900 1920 1940 1960 1980 2000 2020 2040 2060 2080 2100

Hadley Centre for Climate Prediction and Research

Global mean precipitation predictions

Ensembles of four predictions of precipitation (rainfall and snowfall) resulting from ‘business as usual’ changes in greenhouse gases following on from observed changes since 1860 (blue curves). The addition of sulphate aerosol cooling is shown in the green curves.


–21860

8

6

4

2

0

1880 1900 1920 1940 1960 1980 2000 2020 2040 2060 2080 2100

Tota

l pre

cipi

tatio

n (%

cha

nge)

Change in annual temperatures for the 2050s

The change in annual temperatures for the 2050s compared with the present day, when the climate model is driven with an increase in greenhouse gas concentrations equivalent to about a 1% increase per year in CO2. The picture shows the average of four model runs with different starting conditions.


Observed change in annual precipitation for the 2050s

The change in annual precipitation for the 2050s compared with the present day, when the climate model is driven with an increase in greenhouse gas concentrations equivalent to about a 1% increase per year in CO2. The picture shows the average of four model runs with different starting conditions.


IMPACTS UNDER NO MITIGATION

Annual runoff

Percentage change in 30-year average annual runoff by the 2080s.

University of Southampton

Population under extreme water stress

Change, due to climate change, in the number of people living in countries with extreme water stress.

0

40

80

120

2020s 2050s 2080s

Popu

latio

n (m

illio

ns)


Crop yield change 2020s, )2050s,2080s

2020s 2050s 2080s

% c

hang

e in

pric

es fr

om 1

990

base

line

10

8

6

4

2

0

–22020s 2080s 2020s 2080s

40004200

38003600340032003000280026002400

2050s 2050s

Cer

eal p

rodu

ctio

n (m

mt)

Referencescenario

Climate changescenario

2020s 2050s 2080sAddi

tiona

l milli

ons

of p

eopl

e at

risk

of h

unge

r

50454035302520151050

Additional people at risk of hunger under the climate change scenario (0 = Projected reference case).

Projected global cereal production for reference case and the climate change scenario.

Percentage change in global cereal prices under the climate change scenario (0 = Projected reference case).

People at risk from sea-level rise

Percentage change in the number of people at risk under the sea-level rise scenario and constant (1990s) protection (left bar) and the sea-level rise scenario and evolving protection (right bar).

2050s2020s 2080s

700

400

500

600

100

300

200

0

% in

crea

se

Middlesex University / Delft Hydraulics

IMPACTS UNDER SOME/MUCH MITIGATION

Emissions and concentrations of CO2 from unmitigated and stabilising emission scenarios

Unmitigated emissions 750 ppm stabilisation 550 ppm stabilisation

10

5

0

15

20

Ant

hrop

ogen

ic C

O2

emis

sion

s (G

tC/y

r)

2000 2050 2100 2150 2200 2250 2300 2350C

O c

once

ntra

tion

(ppm

)2

1000

950

900

850

800

750

700

650

600

550

500

450

400

3502000 2050 2100 2150 2200 2250 2300 2350


Global average temperature rise from unmitigated and stabilising emission scenarios

1900 2000 2100 2200

0

2

4

Glo

bal t

empe

ratu

re c

hang

e (°

C)

3

1



Temperature riseAnnual average, from the present day to the 2080s


cUnmitigated Emissions

c

c Stabilisation of CO2 at 550ppm

Stabilisation of CO2 at 750ppm

Change in precipitationAnnual average, from the present day to the 2080s

cUnmitigated Emissions

c




Changes in river runoff from the present day to the 2080s

Unmitigated emissions

Stabilisation of CO2 at 750 ppm Stabilisation of CO2 at 550 ppm

–75 –50 –25 –5 to 5 25 50 75Change in annual runoff (%)


Changes in water stress from the present day to the 2080s

01 12 23 34 4

Billions of people

Increased water stressDecreased water stress


Unmitigated Emissions 750 ppm Stabilisation 550 ppm Stabilisation

Changes in crop yieldfrom the present day to the 2080s



University of East Anglia

Potential change in cereal yields (%)

10 – 5

0 – -2.5

-5 – -10-2.5 – -5

-10 – -20

2.5 – 05 – 2.5

No data

Global number of people floodedunder three emissions scenarios

100

80

60

40

20

0

Peop

le fl

oode

d (m

illio

ns/y

ear)

2020s 2050s 2080s


University of Middlesex

No climate change

People flooded by region60

0

10

20

30

40

50

Southern Mediterranean

West Africa East Africa South Asia SE Asia

Peop

le fl

oode

d (m

illio

ns/y

ear)

Unmitigated emissions 750 ppm stabilisation 550 ppm stabilisation No climate change


Island people flooded600

500

400

300

200

100

0Caribbean Indian Ocean

small islandsPacific small islands

Peop

le fl

oode

d (th

ousa

nds/

year

)University of Middlesex

Unmitigated emissions 750 ppm stabilisation 550 ppm stabilisation No climate change

Malaria transmission Change in duration of season, 2080s


Stabilisation at 750 ppm Stabilisation at 550 ppm

2 to 5 months 1 to 2 months –2 to –1 months –5 to –2 months

London School of Hygiene and

Tropical Medicine

Millions at Risk in the 2080s

0

50

100

150

200

250

300

350

0 0.25 0.5 0.75 1 1.25 1.5 1.75 2 2.25 2.5 2.75 3 3.25Temperature Increase

Addi

tiona

l mill

ions

of p

eopl

e at

ris

k of

hun

ger,

mal

aria

an

d co

asta

l flo

odin

g

0

500

1000

1500

2000

2500

3000

3500

Addi

tiona

l mill

ions

of p

eopl

e at

ris

k of

incr

ease

d w

ater

sho

rtage Risk of water shortage

Risk of malaria

Risk of hunger

Risk of coastal flooding

Legend

Stab

. 550

Stab

. 650

Unm

itiga

ted

emis

sion

s - I

S92a

Stab

. 450

Stab

. 750

Stab

. 100

0

The Cost of Stabilising CO2 Concentrations

The effect of different global economic pathways

Regional enterprise: high pop, mod. growth, (A2)

Local stewardship: ‘semi’-sustainable dev, low pop

(B2)

A2 in 2050s B2

• Pop 11.3 billion• GDP 82 tr $• primary energy 970

GJ/yr• carbon 16 GtC/yr

• Pop 9.3 billion• GDP 110 tr $• primary energy 870

GJ/yr• carbon 11 GtC/yr

0

20

40

60

80

100

120

140

160

180

200

2020 2050 2080

Add

ition

al M

illio

ns o

f Peo

ple

A2 - Regional Enterprise B2 - Local Stewardship

Additional People at Risk of Hunger under the SRES A2 and B2 Scenarios

Costs of 550 Stabilisation assuming different development pathways

($trillion)

Global Non-ann 1 Annex 1

A2 3 - 6 2 - 4 1 - 2

B2 2 - 4 2 - 3 c. 1

Conclusions :

• Stabn at 750 does not avoid most effects. • Stabn at 550 does, but at considerable

cost (= c.20 times Kyoto reductions).• Sustainable development (cf SRES B2

pathway) needs also to be part of the ‘solution’

-200

-180

-160

-140

-120

-100

-80

-60

-40

-20

02020 2050 2080

Mill

ion

Met

ric T

onne

s (m

mt)

A2 - Regional Enterprise B2 - Local Stewardship

The Shortfall in Global Cereal Production for Reference Case and the SRES Scenarios

Millions at Risk in the 2050s

0

50

100

150

200

250

300

350

0 0.25 0.5 0.75 1 1.25 1.5 1.75 2 2.25 2.5 2.75 3 3.25Temperature Increase

Addi

tiona

l mill

ions

of p

eopl

e at

risk

of h

unge

r, m

alar

ia

and

coas

tal f

lood

ing

0

500

1000

1500

2000

2500

3000

3500

Addi

tiona

l mill

ions

of p

eopl

e at

risk

of i

ncre

ased

w

ater

sho

rtage

Stab

ilisa

tion

@ 5

50 p

pmv

Stab

ilisa

tion

@ 7

50 p

pmv

Unm

itiga

ted

emis

sion

s - I

S92a

Risk of water shortage

Risk of malaria

Risk of hunger

Risk of coastal flooding

Legend

Conclusions : 2

• Invest in adaptation, to increase resilience to climate change: technology (eg GM), engineering (eg water use efficiency), institutions. These are ‘win-win’ (eg drought-proofing).

• Invest especially in key vulnerable regions and sectors: Africa, Indian subcont., small islands; water, food, coastal settlement.

• Revise the adaptation/mitigation emphasis:

Change in vegetation biomassfrom present day to the 2230s

–8 –5 –3 –1 1 3 5 8kgC/m2

ITE Edinburgh



c

Vegetation dieback5

1

2

3

4

02000 21002050 2150 2200 2250

Are

a of

veg

etat

ion

dieb

ack

(mill

ion

km2 )

Years


ITE Edinburgh

Uptake of carbon by vegetation

Sink

Source

5

4

3

2

1

0

–1

–2

–31950 20502000 2100 2150 2200 2250

Tran

sfer

of c

arbo

n to

veg

etat

ion

(GtC

/yr)


ITE Edinburgh

Changes in vegetation biomassbetween the present day and the 2080s

–8 –5 –3 –1 1 3 5 8kgC/m2

–8 –5 –3 –1 1 3 5 8kgC/m2

–8 –5 –3 –1 1 3 5 8kgC/m2

0 0.1 1 3 5 10 15kgC/m2

ITE Edinburgh

Unmitigated EmissionPresent Day


Changes in river runofffrom the present day to the 2230s

–75 –50 –25 –5 to 5 25 50 75Change in annual runoff (%)




c

Changes in water stressfrom the present day to the 2080s


Stabilisation of CO2 at 750 ppm Stabilisation of CO2 at 550 ppmStressed country with decrease in stress

Country moves to stressed classStressed country with increase in stress


Conclusions : 3

• Foster adaptation to avoid increased inequality (autonomous adaptn=more unequal effects of climate change).

• Foster increased resilience (especially in the ‘tail’): a) seek the sub-optimal (eg drought resistant/non-max yield crop varieties); b) (many) small vs (few) large actions; c) promote stability (vs growth?).

Rate of sea-level rise

60

40

20

0 1990 2020s 2050s 2080s 2110s 2140s 2170s 2200s 2230s

Rat

e of

sea

-leve

l ris

e (c

m/c

entu

ry)


Global wetland losses

20

15

10

5

02020s 2050s 2080s 2110s 2140s 2170s 2200s 2230s

Frac

tion

of w

etla

nd a

rea

lost

(%)



Coastal floodingChange from the present day to the 2080s


Stabilisation at 750 ppm Stabilisation at 550 ppm

University ofMiddlesex

Malaria transmission seasonEstimated for the present day (falciparum)

London School of Hygiene and Tropical Medicine

People at risk of malaria additionally from climate change

350

300

250

200

150

100

50

02020s 2050s 2080s

Add

ition

al p

eopl

e at

risk

(mill

ions

)


London School of Hygiene and Tropical Medicine

what would be the impacts of climate change … · what would be the impacts of climate change...

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