limits to adaptation ocean acidification congressional briefing 9 november 2009 ken caldeira...

Limits to AdaptationOcean acidification

Congressional Briefing9 November 2009

Ken Caldeira Carnegie Institution & Stanford University kcaldeira@carnegie.stanford.edu

Rain, galoshes, and limits to adaptation

To avoid getting wet, you want to bring an umbrella

To avoid climate risk, you want to reduce carbon dioxide emissions

Kasmira,2009

But to keep your feet dry, you might still need galoshes

To diminish damage from the climate change you can’t avoid, you want to improve adaptive resilience

Just wearing galoshes is not enough

emissions reduction

adaptation

Ischia, Italy

Map created by Norman Einstein

CO2 dissolving shells and skeletonsHall-Spencer / BBC

High CO2 = Invasive grasses

Low CO2

= Native shellfish

Thanks, Jason Hall-Spencer

Chemistry ofocean acidification

Formation of calcium carbonate shells and

skeletons

CO32-

CO O

OCa Ca2+ (dissolved)

H HO

H2O HC

O O

OHCO3

-C

O O

OCO3

2-

Formation of calcium carbonate shells and

skeletons

CO32-

CO O

O

Ca Ca2+ (dissolved)

H HO

H2O HC

O O

OHCO3

-C

O O

OCO3

2-

Formation of calcium carbonate shells and

skeletons

CO32-

CO O

O

Ca Ca2+ (dissolved)

H HO

H2O HC

O O

OHCO3

-C

O O

OCO3

2-

Formation of calcium carbonate shells and

skeletons

CO O

OCa CaCO3 (solid)

H HO

H2O HC

O O

OHCO3

-C

O O

OCO3

2-

Water, dissolved carbon, and shells and skeletons

CaCO3 (solid)C

O O

OCa

H HO

H2O HC

O O

OHCO3

-C

O O

OCO3

2-

Addition of CO2

CaCO3 (solid)C

O O

OCa

H HO

H2O HC

O O

OHCO3

-C

O O

OCO3

2-

CO O CO2

Formation of carbonic acid

CO O

OCa

HC

O O

OHCO3

-C

O O

OCO3

2-HH

CO O

OH2CO3

CaCO3 (solid)

Increasing ocean acidity

CO O

OCa

HC

O O

OHCO3

-C

O O

OCO3

2-H

CO O

OHCO3

-

H H+

CaCO3 (solid)

Increasing ocean acidity

CO O

OCa

HC

O O

OHCO3

-C

O O

OCO3

2-H

CO O

OHCO3

-

H H+

CaCO3 (solid)

Increasing ocean acidity

CO O

OCa

HC

O O

OHCO3

-C

O O

OCO3

2-H

CO O

OHCO3

-

H H+

CaCO3 (solid)

Increasing ocean acidity

CaCO3 (solid)C

O O

OCa

HC

O O

OHCO3

-C

O O

OCO3

2-H

CO O

OHCO3

-

H H+

Attacking a building block for shells and skeletons

CO O

OCa

HC

O O

OHCO3

-C

O O

OCO3

2-H

CO O

OHCO3

-

H H+

CaCO3 (solid)

H

Attacking a building block for shells and skeletons

CO O

OCa

HC

O O

OHCO3

-C

O O

OHCO3

-H

CO O

OHCO3

-

CaCO3 (solid)

H

Dissolving shells and skeletons

CO32-

CO O

O

HC

O O

OHCO3

-C

O O

OHCO3

-H

CO O

OHCO3

-

Ca Ca2+ (dissolved)

H

Dissolving shells and skeletons

CO32-

CO O

O

HC

O O

OHCO3

-C

O O

OHCO3

-H

CO O

OHCO3

-

Ca Ca2+ (dissolved)

H

Dissolving shells and skeletons

CO32-

CO O

O

HC

O O

OHCO3

-C

O O

OHCO3

-H

CO O

OHCO3

-

Ca Ca2+ (dissolved)

Lizard Island

ExpeditionSeptember

2008

We measured of coral skeletal growth rates 40% lower than in the late 1970’s

Distribution of corals andocean acidification

0 1 2 3 4 5

Corrosive OptimalΩAragonite

Carbon dioxide level,

Coral reef distribution

,

and chemical

conditions helping

drive reef formation

Cao and Caldeira, 2008

0 1 2 3 4 5

Corrosive OptimalΩAragoniteCao and Caldeira, 2008

Carbon dioxide level,

Coral reef distribution

,

and chemical

conditions helping

drive reef formation

0 1 2 3 4 5

Corrosive OptimalΩAragoniteCao and Caldeira, 2008

Carbon dioxide level,

Coral reef distribution

,

and chemical

conditions helping

drive reef formation

0 1 2 3 4 5

Corrosive OptimalΩAragoniteCao and Caldeira, 2008

Carbon dioxide level,

Coral reef distribution

,

and chemical

conditions helping

drive reef formation

0 1 2 3 4 5

Corrosive OptimalΩAragoniteCao and Caldeira, 2008

Carbon dioxide level,

Coral reef distribution

,

and chemical

conditions helping

drive reef formation

0 1 2 3 4 5

Corrosive OptimalΩAragoniteCao and Caldeira, 2008

Carbon dioxide level,

Coral reef distribution

,

and chemical

conditions helping

drive reef formation

Rain, galoshes, and limits to adaptation

Kasmira,2009

emissions reduction

adaptation

Adaptation is important, but it is not a substitute for emissions reduction

We need an umbrellaand galoshes

Main points

• Few and limited options for adaptation to acidification– Adaptive capacity of ecosystems can be increased by

reducing other stresses on our ocean environment (overfishing, land-based pollution, habitat loss, etc)

– Management and engineering solutions appear to be feasible only in a few isolated cases

To protect our coastal and ocean environments,

we need to greatly reduce our CO2 emissions soon