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. Modelling environmental and socio-economic impacts of cropland
expansion and conservation policies
Ruth Delzeit, 19.02.24

2. Background
Large potentials
• to close current yield gaps (e.g. Mueller et al. 2012, Mauser et al. 2015, Davis et al. 2017)
• to reduce the globally cultivated area (Folberth et al. 2020, Schneider et al. 2023)
But: cropland is still expanded in many regions, most notably in Africa and South America (Popatov
et al. 2021)
Implications:
• Loss and fragmentation of natural habitat
• GHG emissions due to land-use and land cover change
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Ruth Delzeit, Expert Workshop on Modelling the triple Planetary Crisis: Impacts and Policies, 19.02.24

3. Background
State of the art:
• various studies on future expansion exist (e.g. Schmitz et al. 2014, Tilman et al. 2017) 10 13 20
• most studies explore expansion dynamics by referring to one single future cropland extent
resulting either endogenous from the scenario or exogeneous as a predefined
assumption14,15,45,46. (e.g. Delzeit et al. 2017, Zabel et al. 2019, OECD/FAO 2023)
• only a few capture the interdisciplinary context of the drivers and trade-offs in a global, spatially
explicit global-to-local-to-global research framework (e.g. Molotoks et al. 2018)
• Spatial data on potential future expansion area and potential yields is lacking
Objective:
• Identify areas that are under the highest pressure of being transformed into cropland in the future
• Identify areas with strongest trade-offs between food production, mitigation of climate change
and protection of biodiversity
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Ruth Delzeit, Expert Workshop on Modelling the triple Planetary Crisis: Impacts and Policies, 19.02.24

4. An integrated modelling system
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Ruth Delzeit, Expert Workshop on Modelling the triple Planetary Crisis: Impacts and Policies, 19.02.24

5. Adding Biodiversity
Source: Zabel*, Delzeit*, Vaclavik* et al. 2019, Nat Comm
* Equal contributions
Ruth Delzeit, Expert Workshop on Modelling the triple Planetary Crisis: Impacts and Policies, 19.02.24 Universität Basel 5

6. Hotspots of future trade-offs
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Source: Zabel*, Delzeit*, Vaclavik* et al. 2019, Nat Comm
* Equal contributions
Top-pressure regions
in Central America,
tropical Andes, West
and East Africa, India,
Southeast Asia, parts
of Australia
35% protected
Ruth Delzeit, Expert Workshop on Modelling the triple Planetary Crisis: Impacts and Policies, 19.02.24

7. Adding cropland expansion into unmanaged areas
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Ruth Delzeit, Expert Workshop on Modelling the triple Planetary Crisis: Impacts and Policies, 19.02.24
Source: Schneider et al, under review

8. Biodiversity Intactness Index (BII)
Ruth Delzeit, Expert Workshop on Modelling the triple Planetary Crisis: Impacts and Policies, 19.02.24
• PREDICTS database (Contu et al. 2022), and extensions
• Extension of the modelling approach by Purvis et al. 2018
• Estimation of an abundance model
• Estimation of a compositional similarity model
Source: Schneider et al, under review
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9. CO2 emissions caused by cropland expansion
Ruth Delzeit, Expert Workshop on Modelling the triple Planetary Crisis: Impacts and Policies, 19.02.24
Assessment the change in carbon stocks based on the potential natural vegetation cover and
the current land-use state compared to a use as cropland
• Data on the average carbon stocks in biomass and soil of 11 different types of potential natural
vegetation (PNV) depending on their land-use states (cover type) as primary land, secondary
land, pastureland or cropland, based on Hansis et al. (2015)
• Spatial distribution of the different PNV types is provided by Pongratz et al. (2008)
• The spatial distribution of primary land, secondary land and pastureland is assessed in the same
way as for the biodiversity impact assessment on a 1 km spatial resolution referring to HILDA+
land-use data (Winkler et al. 2020) and the integrative global dataset on human influence (Riggio
et al. 2020).
Source: Schneider et al, under review
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10. Scenarios
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+3.6% +3.6%
Source: Schneider et al, under review
Ruth Delzeit, Expert Workshop on Modelling the triple Planetary Crisis: Impacts and Policies, 19.02.24

11. Results – areas of cropland expansion
Ruth Delzeit, Expert Workshop on Modelling the triple Planetary Crisis: Impacts and Policies, 19.02.24
Source: Schneider et al,
under review
potential relative expansion
of current cropland within
each region
absolute regional distribution
of current cropland and the
assessed profitable
expansion areas
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12. Results – areas under pressure under unrestricted expansion
Ruth Delzeit, Expert Workshop on Modelling the triple Planetary Crisis: Impacts and Policies, 19.02.24
Source: Schneider et al,
under review
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13. Results – generated CO2 emissions
Ruth Delzeit, Expert Workshop on Modelling the triple Planetary Crisis: Impacts and Policies, 19.02.24
Source: Schneider et al,
under review
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14. Results – impacts on BII
Ruth Delzeit, Expert Workshop on Modelling the triple Planetary Crisis: Impacts and Policies, 19.02.24
Source: Schneider et al,
under review
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15. Results – impacts of conservation policies
Ruth Delzeit, Expert Workshop on Modelling the triple Planetary Crisis: Impacts and Policies, 19.02.24
Source: Schneider et al,
under review
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16. Some challenges
Definitions and units:
• Yields
• Crop aggregates
• Hectares
What to pass on?
• Harvested vs cultivated area
• Pass on yearly data?
• How often to iterate?
Ruth Delzeit, Expert Workshop on Modelling the triple Planetary Crisis: Impacts and Policies, 19.02.24 Universität Basel 16

17. Summary
• High potential of global conservation policies to reduce the environmental effects of cropland expansion
without compromising agricultural production
→ potential contribution of strategic land-use planning to reconcile food security and economic interests
with the protection of climate and biodiversity
• Flexible, integrative approach for different scenarios
• It takes time to agree and understand a common terminology
• Openness for other disciplines needed
• Approach open for additional features
Ruth Delzeit, Expert Workshop on Modelling the triple Planetary Crisis: Impacts and Policies, 19.02.24 Universität Basel 17

18. Thank you
for your attention.
And thanks to:
Julia M. Schneider, Florian Zabel, Christian Neumann, Tobias Heimann, Ralf Seppelt, Franziska
Schünemann, Mareike Söder, Wolfram Mauser