© Yann Arthus-Bertrand / Altitude

Thomas Stocker & Qin Dahe

Co-Chairs IPCC Working Group I

Switzerland and China

Overview:Climate Change 2013

The Physical Science Basis

www.climatechange2013.org

3

Observations

Understanding

Future

Warming of the climate systemis unequivocal

IPC

C 2

013,

Fig

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PM

.1b,

IP

CC

201

4, F

ig.

1.1

Ano

mal

y (°

C)

rela

tive

to

1961

-199

0

Warming of the climate systemis unequivocal

En

erg

y C

onte

nt (

102

1 Jo

ule

)

1980 1990 2000 2010

300

200

0

100

-1001970

70 mill.TWh

IPC

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014,

SY

R F

ig. 1

.2

(Lüthi et al.,2008, NOAA)

+30%

2014

The concentrations of CO2 have increased to levels

unprecedented in at least the last 800,000 years.

1000 years before present

CO

2 C

once

ntra

tions

(pp

m)

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013,

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.7,

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.6

Global mean surface temperature change from 1986-2005

Further warming will increase the likelihood of

severe, pervasive and irreversible impacts for

people and ecosystems.

IPC

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013,

Fig

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PM

.8,

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014,

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.7

Further warming will increase the likelihood of

severe, pervasive and irreversible impacts for

people and ecosystems.

Change in average surface temperature (1986-2005 to 2081-2100)

RCP8.5

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.8,

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Change in average precipitation (1986-2005 to 2081-2100)

RCP8.5

Further warming will increase the likelihood of

severe, pervasive and irreversible impacts for

people and ecosystems.

RCP 2.6 (annual) RCP 8.5 (annual)

IPCC 2013: Atlas of Global and Regional Climate Projections

Changes in South Europe/Mediterranean (2081-2100)

Further warming will increase the likelihood of severe,

pervasive and irreversible impacts for people and ecosystems.

IPC

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013,

TF

E.2

, F

ig.

2

+19 cm

+63 cm

Further uptake of carbon by the ocean will increase ocean

acidification.

IPC

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013,

Fig

. SP

M.7

c

IPC

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013,

Fig

. SP

M.1

0

790 bill. t C

2°C

Budget for the 2°C target:790 bill t C

CO2 emissions until 2014*:−545 bill t C

CO2 emissions in 2014*: 10.1 bill t C

Remaining emissions:245 bill t C

* up

date

d fr

om I

PC

C 2

013,

WG

I S

PM

Limiting climate change would require substantial and

sustained reductions in greenhouse gas emissions which,

together with adaptation, can limit climate change risks.

2°C world

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.7

4.5°C world2°C world

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Fig

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.7

4.5°C world2°C world

Today we have a choice.