© Ira Block

Global Warming 56 Million Years Ago & What it Means for Us

Scott Wing Dept. of Paleobiology Smithsonian Institution Museum of Natural History

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-800000 -700000 -600000 -500000 -400000 -300000 -200000 -100000 0

CO

2 c

on

cen

trat

ion

in a

tmo

sph

ere

(pp

m)

Years ago

2100 – business as usual

2014

Anthropogenic increase in CO2

Data from NOAA-NCDC

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1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200

2100 – business as usual

2014

1

Inferred pCO2

IPCC 2013 AR5, from Beerling & Royer 2011

Pre- industrial

2015

2100 BAU

Paleogeography 56 million years ago

Estimated Global Mean Temperature (difference from present)

Millions of years ago 60 50 40 30 20 10 0

12

8

4

0

Glo

bal

tem

p (

°C >

pre

sen

t)

Antarctic Ice Sheets

Arctic Ice Sheets

modified from Hansen & Sato 2011, data from Zachos et al. 2008

“Eocene” Climate Enigma

The Eocene climate enigma Warm poles

Dawn Redwood forest Axel Heiberg Island, Canada

D. Greenwood photo

© Ira Block

The Eocene climate enigma

Field Museum

Warm winters palm leaf, Wyoming, USA

© Ira Block

Millions of years ago 60 50 40 30 20 10 0

12

8

4

0

Glo

bal

tem

p (

°C >

pre

sen

t)

Antarctic Ice Sheets

Arctic Ice Sheets

modified from Hansen & Sato 2011, data from Zachos et al. 2008

Paleocene-Eocene Thermal Maximum

(PETM)

“Eocene” Climate Enigma

Estimated Global Mean Temperature (difference from present)

PETM carbon & temperature

Murphy et al. 2010

http://www-odp.tamu.edu/publications/208_IR/208ir.htm

Dissolution of deep ocean chalk

Zachos et al (2005)

Paleocene-Eocene Thermal Maximum (PETM)

• Global warming of 4 to 8 °C

• Extensive marine carbonate dissolution

• Carbon isotope ratio shift of -4‰ to -5‰

• Total duration >100 ky

CONCLUSION

Release of 4,000-7,000 Pg of carbon in a few millennia or less

Potential carbon sources

Methane Hydrates

Thermogenic Methane

Wikipedia

Wildfire

Permafrost

P-E boundary records

Paleogeography by C.R. Scotese, PALEOMAP Project

Google Earth Tom Nash photo

The Bighorn Basin

Tom Nash photo

50 km

Bighorn Basin, Wyoming, Fossil Plant Sites

225 Sites 314 Taxa

1 km strata 7 million yr

Bighorn Basin Plant Fossil Sites

! "

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&#' (! " &#) (! " &#*(! " &#+(! " &##(! " &#, (! " &#- (! " &#%(! " &#$(! "

Millions of Years Before Present

Cu

mu

lative

# F

ossil

Pla

nt

Site

s

P

E

T

M

+ = one leaf fossil site

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%! "

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' #! "

() %*! " () ) *+" () ) *&" () ) *, " () ) *%" () ) *) " () ) *$" () ) *- " () ) *#" () ) *' " () ) *! "

Body

of

CIE

Recovery

Floral Change during the PETM

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-56.0 -55.9 -55.8 -55.7 -55.6 -55.5 -55.4 -55.3 -55.2 -55.1 -55.0

Body CIE

Millions of Years Before Present

Pla

nt

Spec

ies

Tim

e R

ange

s

Recovery

Possible extinctions

PETM-only immigrants

Eocene

Local Extirpations

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() %*! " () ) *+" () ) *&" () ) *, " () ) *%" () ) *) " () ) *$" () ) *- " () ) *#" () ) *' "-56.2 -56.1

Possible Extinctions

Davidia antiqua

Dogwood family

Browniea serrata

Dogwood order

PETM-only, bean family

1.

2.

3. 4.

5.

Post-PETM Immigrants

Alder

Climbing fern

Hickory family Linden family

Sycamore Birch family

Dawn redwood

Ginkgo

Sycamore

Locally extirpated

Katsura tree Oak family

PETM plant geographic change

56 Ma

Floristic Change in Wyoming

1. PETM onset - local/regional EXTIRPATION of temperate deciduous plants (dawn redwood, birch, sycamore, katsura), and immigration of bean family and other dry tropical plants

2. PETM recovery - local/regional EXTIRPATION of bean family et al., return of “natives”, and intercontinental immigration of temperate plants

3. Minor EXTINCTION (~10%)

Aldo Chiappe for National Geographic

PETM – abundant insect damage

© Ira Block © Ira Block

Hyracotherium - Perissodactyla

Primates PETM faunal interchange

Diacodexis - Artiodactyla C. Clark photo

C. Clark photo

Horse body size decrease during PETM

Tom Nash photo

(Secord et al. 2012)

© Ira Block

Four lessons from the PETM

1. A big release of carbon warmed global climate and dissolved deep marine chalk

2. There was probably positive feedback – carbon release increased temperature, releasing more carbon

Geological Release of CO2 and/or methane

Wildfires

Deep ocean CH4 dissociation

Atmosphere warms

Intermittent rainfall

CH4 CO2

Ocean warms

CO

2

CH

4

3. Rapid global warming changed where plants & animals lived, how they interacted, and drove rapid evolution

4. The effects lasted about 200,000 years

Murphy et al. 2010

Taking the Long View

Carbon uptake is very slow

IPCC 5th Assessment Chapter 6 after Archer et al. 2009

5,000 billon tons of carbon into atmosphere (the whole enchilada)

Original CO2 level Bill

ion

s o

f to

ns

of

carb

on

15-40% remains after 10,000 years }

5

4

3

2

1

0

Surf

ace

War

min

g (

C)

1800 2000 2200 2400 2600 2800 3000 Year (CE)

Assumptions:

Carbon emissions ~7 Gt/yr

Emissions increase at ~2%/yr

We burn it all - ~5,000 Gt

Solomon et al. (2009) PNAS

Temperature stays high

1 10 1,000 100 10,000 100,000

-Ho

use

ter

m-

-IP

CC

pro

ject

ion

s-

SOC

IAL-

PO

LITI

CA

L-EC

ON

OM

IC

ECO

LOG

ICA

L-EV

OLU

TIO

NA

RY

natural continent-scale dispersal

rapid evolution (2X body size)

EAR

TH S

YSTE

M

CO2 uptake via

weathering

CO2 surface ocean invasion

CO2 deep ocean mixing

ice sheet response

Evolutionary diversification

$1

bill

ion

$

1 a

t -3

%

-fo

ssil

fuel

s g

on

e?-

-avg

hu

ma

n li

fesp

an

-

-Ja

pa

nes

e m

on

arc

hy-

DURATION IN YEARS (log scale)

-Pre

sid

enti

al t

erm

- -S

ena

te t

erm

-

-avg

. Su

pre

me

Co

urt

-

-Ch

rist

ian

ity-

forest maturation

glacial cycles

-ho

me

mo

rtg

ag

e-

Sea level +7.5m (~25ft) – 5000 CE? (whoops! Greenland Ice Cap melted)

Nickolay Lamm StorageFront.com

NYT Sunday Review November 24, 2012 Data from Climate Central

Ginkgo adiantoides 57 million years old

Ginkgo biloba a “living fossil”

Ginkgo leaf surface

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Sto

ma

tal In

de

x (

%)

CO2 (ppm)

error bars = 1s

Stomatal Index vs. pCO2 in Ginkgo biloba

Barclay & Wing in prep

y = 110.18x-0.426

R² = 0.60

y = -0.011x + 12.96

R² = 0.58

Ginkgo adiantoides 56.1 million year old “mummified” leaf

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1,000

-56.8 -56.6 -56.4 -56.2 -56.0 -55.8 -55.6

CO

2(p

pm

)

Time (Ma)

+341

+258

PETM

Temperature increase of ~5 °C from mammal tooth isotopes (Secord et al. 2010)

Temperature increase of ~4 °C from leaf physiognomy

(Currano et al., 2010)

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CO

2(p

pm

)

Time (Ma)

+341

+258

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CO

2(p

pm

)

Time (Ma)

+341

+258

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900

1,000

-56.8 -56.6 -56.4 -56.2 -56.0 -55.8 -55.6

CO

2(p

pm

)

Time (Ma)

+341

+258

+468

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1,000

-56.8 -56.6 -56.4 -56.2 -56.0 -55.8 -55.6

CO

2(p

pm

)

Time (Ma)

+341

+258

MAT

(C

)

Barclay & Wing in prep

CO2 doubles and temperature increases 4-5° C