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. Identifying trade-offs & searching for synergies
Modelling sustainability targets in the water-land-climate nexus
OECD expert modelling workshop
19 February 2024
Astrid Bos

2. › Interaction between
physical processes and
human activities (land use)
Water-land-climate
nexus
19 Feb 2024 2
IPCC, 2019

3. › Hydrology – water cycle:
• movement of water
• distribution of water
• impacts of human use
Water-land-climate
nexus
19 Feb 2024 3
Vargas Godoy et al
(2021)

4. › Climate related natural
processes
– solar radiation, evaporation,
plant growth
› Land use
– agriculture (crops + livestock)
– forestry
› Climate change
– land use emissions = 23%
› Climate change mitigation
– Emissions ↓
– Carbon sequestration ↑
Water-land-climate
nexus
19 Feb 2024 4

5. › Interaction of
land cover (physical)
& land use (human)
system
– Land use
– Carbon cycle
– Water use
– Agro-economy
IMAGE-land
19 Feb 2024 5

6. 6
19 Feb 2024
Earth system
IMAGE land-management:
5 arc-min grid
• Land-use allocation
• Livestock and forestry systems
• LU emissions and land-based mitigation
MAGNET agro-
economic feedbacks:
• Climate impacts
• Land availability
• Location effects on
yields
TIMER/FAIR climate & energy:
Regional:
• Energy & Industry GHG emissions
• Bio-energy demand
• Carbon prices
MAGICC simple
climate model
30 arc-min grid
• Temperature
• Precipitation
LPJmL dynamic vegetation:
30 arc-min grid
• Carbon cycle
• Hydrology
• Crop & grass yields
Inputs
• GDP and population
• Crop/livestock efficiency
• Scenario assumptions
MAGNET agro-economy:
Regional:
• Food consumption
• Agricultural production and
in/extensification
• Crop/livestock trade
Land use and management
Socio-economic development Agricultural economy

7. 3 IMAGE studies on the nexus
19 Feb 2024 7
• Global Land Outlook 2
• Future Water Challenges
• Water-land-food-climate nexus

8. Global Land Outlook 2
19 Feb 2024 8
• 3 scenarios
▪ Baseline
▪ Restoration (5 billion ha)
▪ Restoration & Protection (+400mln natural land)
• Effects of land restoration on: natural area,
biodiversity, soil organic carbon, agricultural
yields, water regulation and carbon storage
• Comparison:
▪ Scenario to baseline
▪ Change of time (2015-2050)
▪ Comparison with current global restoration
commitments

9. Global Land Outlook 2
changes under the baseline 2015-2050
19 Feb 2024 9

10. Global Land Outlook 2
potential benefits of restoration & protection
19 Feb 2024 10

11. Global Land Outlook 2
trade-offs and regional effects
19 Feb 2024 11

12. Future Water Challenges
19 Feb 2024 12
› Bending the trend on water impacts and climate vulnerability
› Climate related challenges:
– too little
– too much
– too dirty
– impacts on biodiversity
› Business-as-usual vs. high ambition pathway

13. 19 Feb 2024 13
Future Water Challenges
Business-as-usual (left bars) vs.
high ambition pathway (right)
Improvement or deterioration of
impact indicators

14. Water-land-food-climate nexus
19 Feb 2024 14
› SDGs & planetary boundaries
› Model comparison: IMAGE & MAgPIE
› Quantifying trade-offs & synergies
› 6 scenarios:
– 1 reference scenario: SSP2
– 4 scenarios, with measures in 1 nexus dimension each
▪ Water
▪ Land
▪ Food
▪ Climate
– 1 integrated scenario
Doelman
et al
2022 ERL

15. Water-land-food-climate nexus
19 Feb 2024 15
Nexus measures:
– Water:
▪ protecting environmental flow requirements
▪ improved nitrogen use efficiency
– Land:
▪ protecting 50% of terrestrial natural land
▪ improved nitrogen use efficiency
– Food:
▪ healthy diets
▪ reduced food waste
– Climate:
▪ forest protection
▪ Bioenergy
▪ reduced non-CO2 emissions
Doelman
et al
2022 ERL

16. Water-land-food-climate nexus
19 Feb 2024 16
Doelman
et al
2022 ERL
SCENARIO
Measures REF WATER LAND FOOD CLIMATE TOTAL
Environmental flow
requirements
Limit water extraction,
ensuring sufficient water to
ensure a fair condition of
aquatic ecosystems
Limit water extraction,
ensuring sufficient water to
ensure a fair condition of
aquatic ecosystems
Biodiversity protection
Biodiversity protection
extended to 50% of all
terrestrial ecoregions by
2050
Biodiversity protection
extended to 50% of all
terrestrial ecoregions by 2050
Fertilizer efficiency
Strong increase in fertilizer
efficiency
Strong increase in
fertilizer efficiency
Moderate increase in
fertilizer efficiency
Very strong increase in
fertilizer efficiency
Diet change
Diet change towards
healthy diets by 2050 as
proposed by Willet et al.,
2019
Diet change towards healthy
diets by 2050 as proposed by
Willet et al., 2019
Food waste
50% reduction in food
waste 50% reduction in food waste
GHG price
2030: 55 US$/tCO2
2050: 87 US$/tCO2
2030: 55 US$/tCO2
2050: 87 US$/tCO2
Bio-energy production
2030: 61 Ej/yr
2050: 96 Ej/yr
2030: 61 Ej/yr
2050: 96 Ej/yr
Climate impacts RCP 6.0 RCP 6.0 RCP 6.0 RCP 6.0 RCP 2.6 RCP 2.6

17. Water-land-food-climate nexus
19 Feb 2024 17
– Trade-offs:
▪ Climate mitigation + land protection vs
food prices + water withdrawal
– Synergies:
▪ Diet + waste measures & all nexus indicators
Doelman
et al
2022 ERL

18. › Sectoral scenarios
› Integrated scenarios
– do-no-harm / optimal synergies
– implications of slow/fast action
› Combination of both set of
scenarios needed →
– identifying synergies
– quantification of trade-offs
Towards the OECD
Environmental Outlook
19 Feb 2024 18

19. Contact:
Detlef van Vuuren
detlef.vanvuuren@pbl.nl
Elke Stehfest
elke.stehfest@pbl.nl
Jonathan Doelman
jonathan.doelman@pbl.nl
Astrid Bos
astrid.bos@pbl.nl
Further reading
› IMAGE
www.pbl.nl/image
› IMAGE model description
https://www.pbl.nl/en/publications/integrated-
assessment-of-global-environmental-change-
with-image-30-model-description-and-policy-
applications
› Global land outlook
https://www.pbl.nl/en/publications/the-global-
potential-for-land-restoration-scenarios-for-the-
global-land-outlook-2
› Future Water Challenges
https://www.pbl.nl/en/publications/policy-
summary-of-the-geography-of-future-water-
challenges-bending-the-trend
› Global water-land-food-climate
nexus study
Doelman et al 2022 ERL
https://doi.org/10.1088/1748-9326/ac5766
19 Feb 2024 19
Thank you!