Presentation by Bart van den Hurk (WGII Co-Chair, IPCC AR7, Deltares) at the Climate Adaptation Symposium 2023, during the Delft Software Days - Edition 2023 (DSD-INT 2023). Wednesday, 29 November 2023, Delft.

1. Delft Software Days (DSD-INT 2023)
29 November 2023
IPCC Working Group II: From AR6 to AR7
Modelling implications
Bart van den HURK
WGII Co-Chair, IPCC AR7

2. AR6 Synthesis Report SPM Figure 4a
Headline statement from AR6

3. The year 2023

4. The year 2023

5. The year 2023

6. IPCC Interactive Atlas, 2021
The silent disaster
Anneal mean
precipitation change
(%)
Mean temperature change (C)

7. IPCC Interactive Atlas, 2021
The silent disaster
Anneal mean
precipitation change
(%)
Mean temperature change (C)

8. IPCC Interactive Atlas, 2021
The silent disaster
Anneal mean
precipitation change
(%)
Mean temperature change (C)
World Weather Attribution, 2023

9. Special report on Cities and Climate Change
• Supported by Governments & UN-Habitat, C40 Cities, ICLEI, UCLGs, GCOM…
• Significant interest from practitioner, decision-making, and advocacy communities
• Involves contributions from all Working Groups
• Experts from many disciplines and including practitioners
The first report in AR7

10. • Mapping mitigation strategies in
system transitions
• For different urbanization typologies
• Evaluation potential of strategy
For SR-Cities:
→ Bring in cost/benefit analyses
→ Guidance for prioritization
dependent on potential and
development stage
→ Highlighting trade-offs and dilemmas
An action-oriented assessment

11. Example of “action oriented” impact modelling study

12. A rare event – at this location
Precipitation 13 juli Precipitation 14 juli
Near surface
Middle Atmosphere

13. Evaluation with climate statistics
No comparable
amounts in
summer

14. Was it climate change?
• In this area it never happened
before

15. Was it climate change?
• In this area it never happened
before
• In some of these areas similar
“water bombs” were recorded →
“july 2021” ~once per 400 yrs
• Climate increases probability but
with very uncertain extent
(+20 to + 800%)

16. What if the precipitation fell elsewhere?
“Free” draining area
Polder areas
close/below sea
level
https://publications.deltares.nl/11206890_010_0006.pdf

17. Drained regions
• Rapid and uncontrolled discharge → cascade of
peak levels
• Water damage → water safety

18. Polder areas
• Pumping capacity ~20mm/day
• Multiple polders drain at same discharge channels
• Long duration high water levels in large area
Water depth
200 mm
20
mm/day

19. • Climate is speaking for itself, the urgency
is on the action
• We’re seeking not only impact
assessments, but also action impact
assessments
• Engagement with action holders is more
needed than ever
Personal note, Bart van den Hurk
The AR7 messages

20. For more information: IPCC Secretariat: ipcc-sec@wmo.int IPCC Press Office: ipcc-media@wmo.int Visit ipcc.ch
@IPCC_CH
#IPCCReport
@IPCC @IPCC
linkedin.com/
company/ipcc
Thank you!