Forest Ecosystems: Tools to address climate change impacts and adaptation Brent Sohngen

Presentation Title

Capacity Building Programme on the Economics of AdaptationSupporting National/Sub-National Adaptation Planning and Action

Forest Ecosystems: Tools to address climate change impacts and

adaptation

Brent SohngenDepartment of Agricultural, Environmental &

Development Economics,[email protected]

The views expressed are those of the presenter and should not be attributed to either UNDP or USAID. Furthermore, it is strongly recommended that both the PowerPoint slides and the videos of the presentation of content included herein are viewed in conjunction in order that statements appearing in the PowerPoint slides are not interpreted out of context.


Model for measuring economic effects in forestry

Adaptation of Forests and People to Climate Change. 2009. Alexander Buck, Pia Katila and Risto Seppälä. (eds.). IUFRO World Series Volume 22. Helsinki. 224 p.


Ecosystem impacts that affect forestry

• Productivity changes – Will forests grow faster or slower with climate

change? Where will the changes occur?– CO2 fertilization (e.g., Norby et al., 2006).– Warmer and wetter increases growth; while

warmer and drier slows growth.

– Some current evidence that historical climate change and CO2 change have increased productivity to date (e.g., Myneni et al., 1997; Boisvenue and Running, 2006; McMahon et al., 2010).


• Disturbance– Forest fires increase and reduce standing stock

(Westerling et al., 2006; Marlon et al., 2012)– Tropical regions potentially experience increases in

emissions

• Species/biome shifts – Prasad and Iverson; Woodall et al. (2009)

Ecosystem impacts that affect forestry


How do ecosystem models work?

Total C = 50 Total C = 65

Per hectare basis:

TotalCt = TotalCt-1 + NPPt-1 – decompt-1 - disturbancet-1

For all hectares, adjust for forest area.

Focus on measuring changes in carbon stock as a functionof various ecological processes affecting carbon

Time


Ecosystem measurement: DGVM


DGVM Output

• MC1 model (MAPPS and Century Model)– Bachelet et al.

• Spatial• Intertemporal• Differs by climate scenario

– A2, A1b scenarios

– CSIRO, Hadley, MIROC models


Shift in potential forest areaExample for single climate scenario

MIROC A1b 2005


MIROC A1b 2095

Shift in potential forest areaExample for single climate scenario


Shift in total carbonMIROC A1b 2005


Shift in total carbonMIROC A1b 2095


Ecosystem Adaptation: Net Primary Productivity 2015-2095 (% change relative

to 2005)

A1B A2


A1b A2

Ecosystem Adaptation: Area Change 2015-2095 (% change relative to 2005)


A1b A2

Ecosystem Adaptation: % burned per year 2015 - 2095


Ecosystem Adaptation: Total carbon change 2015-2095 (% change relative to

2005)

A1b A2


Variation across climate models


Incorporating humans: Economic modeling

Adaptation of Forests and People to Climate Change. 2009. Alexander Buck, Pia Katila and Risto Seppälä. (eds.). IUFRO World Series Volume 22. Helsinki. 224 p.


Economic models of forests

• Must:– Manage stocks of trees (harvesting/replanting)– Respond to land use change (conversion/regenerate)– Account for prices (either endogenously or exogenously)

• Many important trends influencing forests already underway– Increasing use of non-indigenous short-rotation species.– Growing demand in developing world, particularly Asia.– Demand rising both for traditional forestry and energy.– Rising opportunity costs for land leading to land use change.– Efforts to protect forests from land use change.

• Climate change adds perturbations to this complex management picture.


Ecosystem measurement: DGVM


Integrating ecosystem impacts into forestry models

• Productivity: shift the yield of forests over time in response to climate change

• Shift occurs slowly


Integrating ecosystem impacts into forestry models

• Disturbance: Stock is lost instantaneously through fires, or other non-human disturbance.

• Increasing evidence these changes occur worldwide.

Va

VCa


Global Forest and Land Use Model

• Maximize PV of CS minus costs– Single global demand– 250 ecosystem and management types

differentiated by costs. – Land rents account for competition with other

uses (rising land rents induce land use change).

• Climate Scenarios– Adjust yield function– Adjust equation of motion– Impose constraints on available land area.


Adaptations Incorporated

• Manage existing stock by– changing rotations (e.g., harvest early if dieback

occurring)– salvage

• Adjust where species grow: – Replant new species if growing and economic

conditions (e.g., prices) warrant.

• Manage future stock by – Changing rotations– Changing management & investments


Analysis

• Climate Change: • A2, A1b scenarios• CSIRO, Hadley, MIROC models

• Ecological Analysis: DGVM• MC1 model (MAPPS and Century Model)

• Economic Analysis:• Global Land Use Model


Economic Results: Prices

• Change in price range = -7% to +2%• Hadley & Miroc have mostly lower prices • (7% max)


Economic Results: Forest areaRelative to baseline


Economic resultsChange in output relative to baseline


Example: China

• Why do economic and ecological results diverge?• Effective yield increase more modest than NPP

gains projected by ecosystem model


Example: China

• Markets only use some of the new land available.


Example: China

• Dieback is increasing…


Example: China

• Output changes most in NE (down) and South (up)


Economic results: welfare(million US$/yr)

Consumer Impact

Producer Impact

Net Impact

China $773 ($1,116) ($343)South Asia $223 ($200) $23

SE Asia $361 ($442) ($81)East Asia $11 ($106) ($95)

Consumer Impact

Producer Impact

Net Impact

China $676 ($1,387) ($711)South Asia $195 ($289) ($94)

SE Asia $316 ($283) $33East Asia $10 ($109) ($100)

AVERAGE A1B

AVERAGE A2


Annual Producer WelfareComparison of A1b and A2 averages


Annual producer effectsRange across climate scenarios


Economic model estimates of carbon flux


Challenges for conservation

• Shifting biomes– Large potential effects across the range of

ecosystems

• Declining forestland area– Particularly in tropics

• Changing productivity and disturbance


Shifts in potential forest area

MIROC A1b 2005


MIROC A1b 2095

Shifts in potential forest area


Implications for Conservation

Harris et al., 2008


China: Change in forest area and carbonMIROC A1b

Forest Area

Forest Area

Forest Carbon Forest Carbon


SE Asia change in forest area and carbonMIROCA1b

Forest Area

Forest Carbon


Issues to consider

• Costs of maintaining existing ecosystems– Harvest, replant, etc.– Opportunity costs (other uses) important.

• Costs of establishing new forests– Length of time to establish a new forest

• Protected area management– When to give up?


Conclusions

• Climate change has relatively modest impacts on global forest prices and outputs.– Although large changes in forest management

occur and regional effects are large.

• Output falls in most of Asia, albeit modestly in most areas.– Lower prices lower investments.

• Large range across ecosystem scenarios• Carbon flux is positive in initial periods.• Large implications for conservation based on

protected areas.

Documents

Forest Ecosystems: Tools to address climate change impacts and adaptation Brent Sohngen