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Global Biodiversity Scenarios

Socio-economic and ecological drivers affectingbiodiversity change in the next century

Osvaldo E. SalaBrown University

Aspen Global Change Institute- 21-24 July 2005

ScenariosScenarios are plausible, challenging,and relevant stories about how thefuture may unfold that can be told bothin words and numbersScenarios are not forecasts, projectionsor predictionsScenarios illuminate costs and benefitsof different pathsScenarios should provide guidance foraction

MODELS

SCENARIOS

STORIES

QUALITATIVE

QUANTITATIVE

Naki_enovi_ et al. 2000

Conceptual FrameworkHuman

Behavior

EcosystemFunctioning

Biodiversity

DirectDrivers

Indirect Drivers

Human Well-being *

*

DIRECT DRIVERS

CHANGES IN:

• LAND USE• CLIMATE• ATMOSPHERIC COMPOSITON• NITROGEN DEPOSITION• BIOTIC EXCHANGE

INDIRECT DRIVERS

• POPULATION GROWTH• DEGREE OF GLOBALIZATION• SOCIO-ECONOMIC DEVELOPMENT• TECHNOLOGICAL PROGRESS

First approximation

“Business-as-usual” socio-economicscenario

Different scenarios respond to currentecological uncertainty

Expected changes in drivers

0

1

2

3

4

5

Arctic

Alpine

Boreal

Grassla

nd

Savan

naMed

Desert

N Temp

S TempTro

pic

Impa

ct o

n bi

odiv

ersi

ty

Land-useClimate N depositionBiot ExchCO2

Sala et al. 2000 Science 287:1770

Biome Sensitivity

0

1

2

3

4

5Ar

ctic

Alpi

neBo

real

Gra

ssla

ndSa

vann

aM

edDe

sert

N te

mp

S te

mp

Trop

ic

Impa

ct o

n B

iodi

vers

ity

Land-use

Climate

N-deposition

CO2

Sala et al. 2000 Science 287:1770

DRIVERS

ΔCO2

ΔClimate

ΔLandUse

ΔN

ΔBiotic Ex

ΔBiodiversity

Biome

SensitivityCO2

SensitivityClimate

SensitivityLand Use

SensitivityN

SensitivityBiotic Ex

NO INTERACTIONS (SUM)

ΔBiodiversity

ΔBiodiversity

ΔBiodiversity

ΔBiodiversity

ΔBiodiversity

BIOMESENSITIVITY

ANTAGONISTIC (MAX)DRIVERS

ΔCO2

ΔClimate

ΔLandUse

ΔN

ΔBiotic Ex

ΔBiodiversity

Biome

SensitivityCO2

SensitivityClimate

SensitivityLand Use

SensitivityN

SensitivityBiotic Ex

ΔBiodiversity

ΔBiodiversity

ΔBiodiversity

ΔBiodiversity

ΔBiodiversity

BIOMESENSITIVITY

SYNERGISTIC (MULT)DRIVERS

ΔCO2

ΔClimate

ΔLandUse

ΔN

ΔBiotic Ex

ΔBiodiversity

Biome

SensitivityCO2

SensitivityClimate

SensitivityLand Use

SensitivityN

SensitivityBiotic Ex

ΔBiodiversity

ΔBiodiversity

ΔBiodiversity

ΔBiodiversity

ΔBiodiversity

BIOMESENSITIVITY

Relative effects of drivers

0

0.2

0.4

0.6

0.8

1

Land use

Climate

N deposit

ion

Biotic Exc

hange

Atmos C

O 2

Rel

ativ

e ef

fect

of d

river

s

Sala et al. 2000 Science 287:1770

Differences among biomes

0.2

Tropical

0

0.40.60.81

Savanna

00.20.40.60.8

1

S Temp

00.20.40.60.8

1

N Temp

00.20.40.60.81

00.20.40.60.8

1 Grassland

Boreal

00.20.40.60.8

1 Alpine

00.20.40.60.8

1Desert

00.2

0.40.60.8

1

Mediterranean

00.2

0.40.60.8

1 Arctic

00.2

0.60.8

1

0.4

Rel

ativ

e B

iodi

vers

ity C

hang

e

Land

use

Atm

os C

O 2

N De

posi

tion

Clim

ate

Biot

ic E

xcha

nge

Land

use

Atm

os C

O 2

N De

posi

tion

Clim

ate

Biot

ic E

xcha

nge

Land

use

Atm

os C

O 2

N De

posi

tion

Clim

ate

Biot

ic E

xcha

nge

Land

use

Atm

os C

O 2

N De

posi

tion

Clim

ate

Biot

ic E

xcha

nge

Land

use

Atm

os C

O 2

N De

posi

tion

Clim

ate

Biot

ic E

xcha

nge

Land

use

Atm

os C

O 2

N De

posi

tion

Clim

ate

Biot

ic E

xcha

nge

Sala et al. 2000 Science 287:1770

Relative Biodiversity ChangeNo Interactions

Sala et al. 2000 Science 287:1770

Sala et al. 2000 Science 287:1770

Relative Biodiversity ChangeAntagonistic Interactions

Sala et al. 2000 Science 287:1770

Relative Biodiversity ChangeSynergistic Interactions

Limitations

Single socio-economic path

Coarse scale of analysis

Second approximation

Millennium Assessment Scenarios

Multiple socio-economic paths Finer spatial scale than previous exercise

Millenium Assessment Scenarios

4 types of scenarios OS – Order from Strength GO – Global Orchestration TG – Technogarden AM – Adaptive Mosaic

Relationships and Interactions of People and Nature

connected

disaggregated

responsive proactive

Global Orchestration

Order from Strength

Technogarden

Adaptive Mosaic

Scenarios Framework

Adaptive Mosaic

•Local and regional flexibility•Adaptation and innovation to manage ecosystem services

Technogarden

•Technological innovation the most common approach for addressing human needs and ecosystem services

Order from Strength

•Security leads the rich to protect their borders•A world of conflict and poverty outside the borders•Negative consequences for ecosystem services

Global Orchestration

•Fair global policies for economics and environmental commons

Fair Global Local/Regional

Technological

TECHNOGARDENTECHNOGARDEN

GLOBAL GLOBAL ORCHESTRATIONORCHESTRATION ADAPTIVE MOSAICADAPTIVE MOSAIC

Population drivers MA Scenarios

4000

6000

8000

10000

12000

1995 2020 2050 2100Year

Popu

latio

n (m

illio

ns)

Order from StrengthGlobal OrchestrationTechnogardenAdaptive Mosaic

Rate of disappearance of forest landMA Scenarios

0.2

0.3

0.4

0.5

0.6

0.7

1995 2020 2050 2100Year

Perc

ent p

er y

ear

Order from StrengthGlobal OrchestrationTechnogardenAdaptive Mosaic

Development of MABiodiversity Scenarios

Direct Drivers

Land-UseChange

Climate Change

Biodiversity Scenarios

0

500

1000

1500

2000

2500

3000

0 200 400 600 800

Area (km2)

No.

of s

peci

es S = C * Az

Species Area Relationship (SAR)

UNKNOWNS• Δ A = changes in area

• C = Original speciesdensity

• Z = slope of the species-area curve

1970 2050 : Global Orchestration

2050: Order from Strength

Land cover change in IMAGEscenarios

Species numbers of vascular plants

Source: Barthlott et al., University of Bonn

Estimate species density foreach combination of IMAGE region and each biome type

18 regions

14 biomes

Matrix

Sala et al., in press, Millennium Assessment

Species-area relationships ofvascular plants

Biodiversity loss for MA scenarios

Sala et al., in press, Millennium Assessment

80%

85%

90%

95%

100%

1970 1990 2010 2030 2050

Rem

aini

ng d

iver

sity

Order from Strength

Global Orchestration

Techno Garden

Adaptive Mosaic

Loss of biodiversity in vascular plantsScenario: Order from Strength

Sala et al., in press, Millennium Assessment

RegionalBiome

0

5

10

15

20

25

Tundra

Boreal

Forest

Cool C

onife

r

Temp.

Mixed

Temp.

Decid.

Warm

Mixe

dStep

peDes

ertScru

b

Savan

na

Trop. W

oodla

nd

Trop. F

orest

% b

iodi

vers

ity lo

st

2050

2020

0

5

10

15

20

25

30

Austra

lasia

Afrotro

pic

Indo-M

alaya

n

Neoarc

tic

Neotro

pic

Palearc

tic

% b

iodi

vers

ity lo

st

2050

2020

Species’ loss rates of MA scenarioscompared to historic rates

Sala et al., in press, Millennium Assessment

Climate change

Sala et al., in press, Millennium Assessment

CURRENTVEGETATION

No species loss if actual vegetation area remains the same

FUTUREVEGETATION

If area shrinks --- loss of species

FUTUREVEGETATION

Effects of climate changeMA Scenarios

Sala et al., in press, Millennium Assessment

Comparison of major drivers on biodiversity loss

Sala et al., in press, Millennium Assessment

Total

0

0.25

0.5

0.75

1

Habitat Loss Climate Change

Bio

dive

rsity

impa

ct

Tundra

0

0.25

0.5

0.75

1

Habitat Loss Climate ChangeB

iodi

vers

ity im

pact

Boreal Forest

0

0.25

0.5

0.75

1

Habitat Loss Climate Change

Bio

dive

rsity

impa

ct

Tropical Forest

0

0.25

0.5

0.75

1

Habitat Loss Climate Change

Bio

dive

rsity

impa

ct

Temperate Forest

0

0.25

0.5

0.75

1

Habitat Loss Climate Change

Bio

dive

rsity

impa

ct

Warm Mixed

0

0.25

0.5

0.75

1

Habitat Loss Climate Change

Bio

dive

rsity

impa

ctOS GO TG AM

ConclusionsDiversity of vascular plants sharply declinedin all four MA scenarios during the 2000-2050-time period.Order from Strength was the scenario thatexperienced the largest losses of vascular-plant species whereas Technogarden andAdaptive Mosaic were the scenarios with thesmallest losses.The different biomes and regions of the Earthlost species at different rates during the 2000-2050 period.

ConclusionsBiodiversity Millennium Development Goals(MDG) not met by Order from Strength and Global

Orchestration barely met by Technogarden and Adaptive Mosaic

At the global level and across all scenarios,land-use change was the dominant driver ofbiodiversity changeScenarios could be a powerful tool to assistpolicy makers and communicate to thegeneral public

Layers of uncertaintyClimate

Data 20% of precipitation

trend due to instrumentchange

Emission scenariosClimate sensitivity threshold responses? clouds?

Models 3°C difference in model

output for sameemission scenario

BiologyData sampling gaps (space &

time) bias (taxon, observer) data absence = real

absence?Basic knowledge (lack ofknowledge of processes)Models

output

Layers of uncertaintyClimate

Data 20% of

precipitation trenddue to instrumentchange

Emission scenariosClimate sensitivity threshold

responses? clouds?

Models 3°C difference in

model output forsame emissionscenario

BiologyData sampling gaps

(space & time)

bias (taxon,observer)

data absence =real

absence?Basic knowledge(lack of knowledgeof processes)Models

output

Human Behavior

Pop growth

Degree of Glob

Socio-eco develop

TechnologicalProgress