This OECD technical workshop will bring together leading experts on economic, biophysical, and integrated assessment modelling of the interactions between climate change, biodiversity loss, and pollution. The workshop will take stock of ongoing modelling efforts to develop quantitative pathways to study the drivers and impacts of the triple planetary crisis, and the policies to address it. The aim is to identify robust modelling approaches to inform the work for the upcoming OECD Environmental Outlook.

1. Biodiversity modeling in
AIM (Asia-pacific Integrated Model)
Shinichiro Fujimori, Kyoto University
On behalf of AIM team
Haruka Ohashi, Tomoko Hasegawa, Kazuaki Tsuchiya, Akiko Hirata,
Tetsuya Matsui, Kiyoshi Takahashi
Feb., 2024@OECD Paris

2. Outline
• Modeling tool
• Biodiversity assessment on climate change impacts and
mitigation
• Land-based CDR (BECCS and afforestation) implications on
biodiversity under climate goals
• Bioenergy potential changes due to biodiversity
conservation

3. Global integrated assessment model AIM
• Environmental assessment
✓ Climate
✓ Air pollution
✓ Biodiversity
• Socioeconomic
assessment associated
with environmental
protection or
environmental impacts
✓ Poverty
✓ Hunger
✓ Health
✓ Macroeconomy

4. AIM-Hub
(AIM-CGE)
Future land-use map
(0.5 degree)
AIM-Biodiversity
Regionally aggregated
land-use and agricultural
information
AIM/PLUM
Biodiversity impact (0.5 arc degrees)
Climate data
(5GCMs)
Climate impact
Land use
change impact
Overall modelling framework for biodiversity assessment
General equilibrium model Land-use downscaling model Biodiversity assessment model
Socioeconomic
assumptions
Environmental
protection

5. AIM-Hub (AIM-CGE)
• General equilibrium
global economic
model
• 43 industrial sectors
(Energy and
agriculture are highly
disaggregated) and 17
region.
• Recursive dynamic
• Domestic and
international market is
assumed
• Emissions; CO2, CH4, N2O, SOx,
NOx, CO, BC, OC, VOC, NH3
Fujimori et al. (2017) GEC, Fujimori et al. (2014) AppEne etc.

6. AIM-PLUM
• Economic model
• Recursive optimization model
• Maximization of land owner’s profit (= revenue - costs)
• Previous-year land-use data is fed to next year.
• Input : Regional aggregated land-use area (from AIM/Hub)
• Output: a fraction of a grid cell occupied by land-use (0 to 1 per grid cell).
• Land-use categories: 7 crop groups (irrigated/rainfed), pasture, forest, other natural
vegetation, afforestation.
• Resolution
• 2005 – 2100 years (1, 5, 10 years)
• 0.5°spatial resolution
• World 17 regions
Hasegawa et al.,(2017) STOTEN etc.

7. AIM-Biodiversity model overview
- Based on species distribution modelling approach using MaxEnt (Phillips et al. 2006)
- 8,428 species in 5 taxonomic groups (vascular plants, amphibians, reptiles, birds, mammals)
Species occurrence Environmental variables
Response curve Habitat suitability
MaxEnt
Ohashi et al. (2019) NatComm etc.

8. Indicator canditates:
• Future potential habitat area
• Percentage change of the number of species losing potential habitat area by >50%
Allometric equations with
species traits database
Database related to dispersal ability and life-
history traits
Statistical model for estimating suitable
habitat from environmental factors.
Present
Suitable habitat
Potential dispersal distance in future
N: No dispersal P: Partial dispersal
Habitat assessment model
F: Full dispersal
Habitat in 2070
Habitat in 2005
Potential dispersal distance
within
65 years
Source
of
the
icon:
http://icooon-mono.com/
Future
Suitable habitat
AIM-Biodiversity

9. Biodiversity implications of Land-based mitigation
measures
• At IPCC AR5 (2013) and SR1.5 (2018), deep
mitigation scenarios have been compiled
• Significant amount of negative emissions
(CDR) would be needed
• BECCS and afforestation are the only
measures in IAMs at that time
• There should be land-related concerns
• Socioeconomic side; food market impacts →
Food security
• Ecosystem side; biodiversity impacts → ????
• Simultaneous climate change mitigation
and impact considerations are needed.
CO2 emissions Land-use under
1.5 degree

10. Land-use change sub-scenarios
Current Mitigation Baseline
Climate change sub-scenarios
RCP2.6 equivalent mitigation SSP1-5 baseline
Scenario RCP Year GCMs 2005 2050 2070 2050 2070
Current –
1960 –
1990
– Current LU
(MIT-2050s)
LU
(MIT-2070s)
LU
(BL-2050s)
LU
(BL-2070s)
Mitigation
(MIT)
2.6
2050s 5 GCMs CC
(MIT-2050s)
LUCC
(MIT-2050s)
– – –
2070s 5 GCMs CC
(MIT-2070s)
– LUCC
(MIT-2070s)
– –
Baseline (BL) 8.5
2050s 5 GCMs CC
(BL-2050s)
– – LUCC
(BL-2050s)
–
2070s 5 GCMs CC
(BL-2070s)
– – – LUCC
(BL-2070s)
Combination of LU/CC scenarios

11. Climate Change and biodiversity
Ohashi et al. (2019) Nature Communications
• Climate change mitigation would bring more benefit in biodiversity
• There should be careful consideration for the adverse-side effects of
land use change
Land use effects
Climate change
effects
MIT: Mitigation = RCP 2.6
BL: Baseline = RCP 8.5
LU：Land Use
CC: Climate Change

12. Climate Change and Biodiversity
Ohashi et al. (2019) Nature Communications
• The similar trend can be seen in all taxonomies.

13. Loss/gain in suitable habitat of 8,428 species under
mitigation (MIT)/ baseline (BL) scenario for SSP1-5
• Similar trends can be seen in
all SSPs.
• Socioeconomic assumptions
can be also large factor to
drive the biodiversity
conditiobns

14. • Evaluate the impacts of large-scale deployment of
BECCS and afforestation on global biodiversity
• Assess the impacts of both climate change and land-
use change due to mitigation measures
simultaneously using an integrated modeling
framework
The next question is ….
https://studentlesson.com/definition-applications-
diagram-types-working-advantages-and-disadvantages-of-
biomass-energy/
Bioenergy cropland
Afforestation
https://www.fao.org/forest-resources-assessment/2020/en/
IPCC (2018)

15. Mitigation
scenario
Climate scenario Summary
Baseline SSP3-7.0 • No special mitigation measures
BECCS SSP1-2.6
• Achieve the 2°C target
• Achieve CDR mainly through the introduction of BECCS
• The forest area is not less than that of the baseline scenario
Afforestation SSP1-2.6
• Achieve the 2°C target
• Achieve CDR mainly through the introduction of afforestation
by making the demand for biofuels as almost zero
Full-mitigation SSP1-2.6
• Achieve the 2°C target
• Allow to use BECCS and afforestation
Scenario settings

16. Evaluation for biodiversity implications
1. Biodiversity loss (gain)
Species richness
(Changes in number of species for each grid)
2. Biodiversity alteration
Compositional similarity
(Changes in species composition for each grid)
A, B, C D,E F, G
Current Future
Changing in number of species
= (future – current) / current
= (4 – 5) /4 = – 0.25
Jaccard similarity index
=
= 2 / (3 + 2 + 2)
Number of species occurred
both in current and future
Total number of
species
/
Negative values mean the loss of biodiversity Lower values mean more progress of species
replacement from current to future
A, B, C D,E F, G
Current Future

17. Changes
in
species
richness
(future
－
current)
/
current
75% percentile
25% percentile
Median
BECCS scenario
Afforestation scenario
Full-mitigation scenario
Baseline scenario
Result 1. Introduction of mitigation measures through BECCS and afforestation had
the potential to reduce risks of future biodiversity loss due to climate change
• Climate change would have a greater impact on diversity than land-use change
• Species richness was slightly better maintained under the BECCS scenario than under the afforestation scenario
Species richness
Increase
Decrease
Similarity
index
75% percentile
25% percentile
Median
Compositional similarity
Species
composition
changes

18. Baseline
Full-mitigation
BECCS
Afforestation
Changes
in
species
richness
(future-current)
/
current
Changing in species richness in 2090
Asia Europe North
America
South
America
Africa
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
Japan
China
India
Rest
of
East
and
South
East
Asia
Rest
of
Asia
New
Zealand
and
Australia
EU
Rest
of
Europe
Former
USSR
Turkey
Canada
USA
Brazil
Rest
of
Brazil
Middle
East
North
Africa
Other
Africa
Result 2. Mitigation measures reduce regional differences in the impacts of climate
change on biodiversity
• In areas where the species richness declines under the Baseline scenario, mitigation measures suppress the loss
of species richness
• In areas where the species richness increases under the Baseline scenario, mitigation measures suppress the
gain of species richness
Changes in species richness
(Baseline / current)
Changes
in
species
richness
（Full-mitigation
/
Baseline）
Baseline: increase in the
species richness
Mitigation: suppress the loss
of species richness
9
11
13
15
Baseline: increase in the
species richness
Mitigation: suppress the gain
of species richness

19. Conclusion
• Climate change mitigation could reduce the risk of future biodiversity loss on the global scale
regardless of land-use change due to the implementation of BECCS or afforestation
Climate change likely to have a greater impact on global biodiversity than land-use change
• Adverse side effects of mitigation measures on biodiversity were concentrated in areas with a
higher contribution to carbon sequestration through land-use change
In both BECCS and Afforestation scenario, regions that contribute to carbon sequestration will take
more negative impacts on diversity
It is important to consider the most suitable measures for each region
considering with the efficiency of carbon sequestration and the biodiversity
conservation simultaneously

20. Bioenergy potential changes associated with
biodiversity conservation
• Conservation priority rank, as
determined by a Zonation
analysis(Moilanen et al., 2005).
• The ranking of each grid cell is
created via a cell removal process.
• This index represents the
percentile of the priority for
protection and larger values imply
a higher priority.
• In the enhanced biodiversity
protection scenario, we further
exclude all the bioenergy
production from the grid cells with
an index above 0.95
Wu et al. (2019) GCB Bioenergy

21. Final remarks
• AIM Integrated assessment modelling framework exchanges
the information among models.
✓ Economic, land and biodiversity models
• The impacts of climate change mitigation and impacts on
biodiversity have been assessed
✓ Mitigation v.s. impacts
✓ BECCS v.s. afforestation
• Biodiversity conservation can change bioenergy and
afforestation potential