Talk on climate variability at Our Common Future conference, Paris, 8th July 2015 Discusses: i) history of global temperature measurements, ii) the recent slowdown in global temperature rise and what it means iii) simulating climate variability, iv) communicating & visualising climate variability

1. Global & regional climate
variability: a pause for thought
Ed Hawkins
National Centre for Atmospheric Science, University of Reading
Thanks to: Rowan Sutton, Doug McNeall, Tamsin Edwards
@ed_hawkins
CFCC 2015 Conference, 8th July 2015

2. Kincer (1933)

3. Callendar (1938)@GuyCallendar

4. Global temperature trends

5. What will the simulations do next?
After Hawkins, Edwards & McNeall, 2014, NCC

6. What will the simulations do next?
After Hawkins, Edwards & McNeall, 2014, NCC

7. What will the simulations do next?
After Hawkins, Edwards & McNeall, 2014, NCC

8. What will the simulations do next?
After Hawkins, Edwards & McNeall, 2014, NCC

9. What will the simulations do next?
After Hawkins, Edwards & McNeall, 2014, NCC

10. What will the simulations do next?
After Hawkins, Edwards & McNeall, 2014, NCC

11. What will the simulations do next?
After Hawkins, Edwards & McNeall, 2014, NCC

12. Visualising variability
Hawkins, Edwards & McNeall, 2014, Nature Climate Change
How to visualise
ensembles:
 Show individual
ensemble
members?
 or just the mean
and standard
deviation?

13. Sutton, Suckling &
Hawkins, 2015

14. Comparing global and UK change
Sutton, Suckling & Hawkins, in press, Phil Trans A

15. Observed Arctic sea ice trends
After Swart et al. 2015

16. Observed Arctic sea ice trends
After Swart et al. 2015

17. Simulating climate variability
IPCC 1st
Assessment
Report, 1990

18. Simulating climate variability
IPCC 1st
Assessment
Report, 1990

19. Summary
 The climate exhibits substantial natural variability
 Short term trends are not necessarily a reliable guide to
expected long term changes
 GCMs show a large diversity in variability for
temperature, precipitation and sea ice. Need to better
understand these differences.
 Appropriate communication & visualisation of regional
variability is essential
 Scrap ‘rainbow’ colour scales [see: tiny.cc/endrainbow]
@ed_hawkins

20. tiny.cc/endrainbow #endrainbow

21. Figure: Reto Knutti
September Arctic
sea-ice extent in two
GCM simulations

22. September Arctic
sea-ice extent in two
GCM simulations
Figure: Reto Knutti
Arctic sea-
ice ‘pause’?

23. Arctic sea-ice variability
Why the differences?

24. Comparing global and regional change
Sutton, Suckling & Hawkins, submitted

25. European summer heatwaves in future