1. The impact of green-house gas emissions,
climate downscaling and land-use change
on Belgian urban heat stress scenarios
Hendrik Wouters, Nicole van Lipzig, Sam Vanden Broucke, Lien Poelmans, Hossein Tabari,
Parisa Hosseinzadeh Talaee, Johan Brouwers, Matthias Demuzere, Dirk Lauwaet, Bino Maiheu,
and Koen De Ridder

2. Rapid changes in global society

3. GHG Emission

4. Land use change

6. “There were more than 400 additional deaths in
Belgium during heat wave in summer 2015”
Belgian Scientific Institute of Public Health
=
~½

7. Objectives
● Hindcast for urban heat stress in Belgium
● Projections
● To quantify the different drivers future HS changes

8. Objectives
● Hindcast for urban heat stress in Belgium
● Projections
● To quantify the different drivers future HS changes

9.    min, max,18.2 29.6 ,i i i
i
HGD T C T C h
 
        
Urban heat stress index
[De Ridder., et al 2015]
● Heat-wave degree days [°C day]:
● Heat wave day hi
● Threshold-based index

10. City centre
Rural area
Heat-wave degrees for Antwerp [C ° day]
Urban heat stress index
[De Ridder., et al 2015]

11. COSMO-CLM
Regional climate model [Rockel et al., 2008]

12. COSMO-CLM
Scenarios Risk assessment
– Land characteristics
– GHG concentration
– Boundary climate
High-resolution
3D climate statistics
GHG Emissions
Land-use change
– Urban heat stress
– Heavy precipitation and floods
– Air pollution
– …
Regional climate model [Rockel et al., 2008]Regional climate model

13. TERRA_URB
Urban land-surface scheme of the COSMO(-CLM) model
[Wouters et al. 2015 (UCLIM); Wouters et al. 2016 (GMDD)]

14. Hiresolution climate modelling
COSMO-CLM
TERRA_ML
Europe: CORDEX.EU domain
COSMO-CLM
TERRA_URB
Brussels
Belgium: CORDEX.be domain
12.5km resolution
2.8km resolution
[Jacob et al.] [Termonia et al.]

15. Reconstruction heat-stress index for
1979-2003

16. Reconstruction heat-stress index for
1979-2003

17. Reconstruction heat-stress index for
1979-2010
COSMO-CLM + TERRA-URB (composite) cascade-nested in ERA-INTERIM

18. Reconstruction heat-stress index for
1979-2010
COSMO-CLM + TERRA-URB (composite) cascade-nested in ERA-INTERIM

19. Reconstruction heat-stress index for
1979-2010
COSMO-CLM + TERRA-URB (composite) cascade-nested in ERA-INTERIM

20. Objectives
● Hindcast for urban heat stress in Belgium
● Projections
● To quantify the different drivers future HS changes

21. Objectives
● Hindcast for urban heat stress in Belgium
● Projections
● To quantify the different drivers future HS changes

22. Impervious surface area [%]
Output from
Spatial model
[Engelen et al., 2011)]
Land use
change

23. Impervious surface area [%]
Land use
change
Business as usual
Output from
Spatial model
[Engelen et al., 2011)]

24. Delta change approach
[Tabari et al., 2014]
● Changes in ensemble statistics are applied to the hindcast
● RCP2.6, RCP4.5, RCP6.5 and RCP 8.5
● 11 GCM models, 31 simulations
→ Three ensemble scenarios:
GHG Emission

25. Delta change approach
(Tabari et al., 2014)
● Offset applied on HISTorical record
● RCP2.6, RCP4.5, RCP6.5 and RCP 8.5
● 11 GCM models, 31 simulations
● → Three scenarios:
Low
temperatures
High
temperatures
GHG Emission
60-year Changes in daily temperatures [°C]
1 2 3 4 5 6 7 8 9 10
0
1
2
3
4
5
bin
Apr may Jun Jul Aug Sep
0
1
2
3
4
5
HIGH
MEDIAN
LOW
Low
temperatures
High
temperatures

27. Urban
Semi-urban
Rural
Clim.spread
Clim.
average

28. Future change heat stress
LAND:2060 GHG:MEDIAN

29. Objectives
● Hindcast for urban heat stress in Belgium
● Projections
● To quantify the different drivers future HS changes

30. Objectives
● Hindcast for urban heat stress in Belgium
● Projections
● To quantify the different drivers for future HS changes

31. Future change heat stress: drivers
(Decomposition methodology: Stein and Alpert, 1993)
Urban
Semi-urban
Rural

32. Future change heat stress: drivers
(Decomposition methodology: Stein and Alpert, 1993)
Urban
Semi-urban
Rural
● Greenhouse gas-induced changes in climate statistics
● Monthly mean temperature change

33. Future change heat stress: drivers
(Decomposition methodology: Stein and Alpert, 1993)
Urban
Semi-urban
Rural
● Greenhouse gas-induced changes in climate statistics
● Monthly-mean temperature change
● Changes in temperature distribution

34. Future change heat stress: drivers
(Decomposition methodology: Stein and Alpert, 1993)
Urban
Semi-urban
Rural
● Greenhouse gas-induced changes in climate statistics
● Monthly-mean temperature change
● Changes in temperature distribution
● High-resolution climate downscaling
● Monthly-mean

35. Future change heat stress: drivers
(Decomposition methodology: Stein and Alpert, 1993)
Urban
Semi-urban
Rural
● Greenhouse gas-induced changes in climate statistics
● Monthly-mean temperature change
● Changes in temperature Distribution
● High-resolution climate downscaling
● Monthly-mean
● Time dependency

36. Future change heat stress: drivers
(Decomposition methodology: Stein and Alpert, 1993)
Urban
Semi-urban
Rural
● Greenhouse gas-induced changes in climate statistics
● Monthly-mean temperature change
● Changes in temperature Distribution
● High-resolution climate downscaling
● Monthly-mean
● Time dependency
● Land-use change

37. Future change heat stress: drivers
(Decomposition methodology: Stein and Alpert, 1993)
Urban
Semi-urban
Rural
● Greenhouse gas-induced changes in climate statistics
● Monthly-mean temperature change
● Changes in temperature Distribution
● High-resolution climate downscaling
● Monthly-mean
● Time dependency
● Land-use change
● Synergy temperature distribution change and downscaling

38. Future change heat stress: drivers
(Decomposition methodology: Stein and Alpert, 1993)
Urban
Semi-urban
Rural
● Greenhouse gas-induced changes in climate statistics
● Monthly-mean temperature change
● Changes in temperature Distribution
● High-resolution climate downscaling
● Monthly-mean
● Time dependency
● Land-use change
● Synergy temperature distribution and downscaling

39. Future change heat stress: drivers
(Decomposition methodology: Stein and Alpert, 1993)
Urban
Semi-urban
Rural
● Greenhouse gas-induced changes in climate statistics
● Monthly-mean temperature change
● Changes in temperature Distribution
● High-resolution climate downscaling
● Monthly-mean
● Time dependency
● Land-use change
● Synergy temperature distribution and downscaling

40. Future change heat stress: drivers
(Decomposition methodology: Stein and Alpert, 1993)
Urban
Semi-urban
Rural
● Greenhouse gas-induced changes in climate statistics
● Monthly-mean temperature change
● Changes in temperature Distribution
● High-resolution climate downscaling
● Monthly-mean
● Time dependency
● Land-use change
● Synergy temperature distribution and downscaling
GHG Emission
1 2 3 4 5 6 7 8 9 10
0
1
2
3
4
5
Low
temperatures
High
temperatures
Temperature change [°C]

41. Future change heat stress: drivers
(Decomposition methodology: Stein and Alpert, 1993)
Urban
Semi-urban
Rural
● Greenhouse gas-induced changes in climate statistics
● Monthly-mean temperature change
● Changes in temperature Distribution
● High-resolution climate downscaling
● Monthly-mean
● Time dependency
● Land-use change
● Synergy temperature distribution and downscaling

42. Wouters et al. (in preparation), Green-house gas induced excess heat waves, heat
islands and urban expansion comprise inordinate future heat stress at the mid-latitude.