1. Perceptions of sea-level change on the Severn Estuary
Dr Merryn Thomas
PhD supervised by Professor Nick Pidgeon, Dr. Lorraine Whitmarsh and Dr. Rhoda Ballinger
ThomasMJ6@Cardiff.ac.uk

2. Rationale
•Understanding public responses to sea-level change is important because perceptions can:
▫contribute to policy making
▫shape risk communications
right to know
buy-in
•To be able to communicate effectively, communicators must know what people already think
•Little is known about how the public understands sea-level change
What do the public think and feel about sea-level change on the Severn Estuary?

3. Project Overview
Expert Perceptions Phase creating an expert model of the risks
•Literature review
•Expert interviews (N=11)
•Semi-structured interviews
•Probability elicitations
•Cognitive mapping
Public Perceptions Phase 1 scoping public perceptions
•Public interviews (N=20)
•Open-ended interviews
•Picture sorting task
•Cognitive mapping
Public Perceptions Phase 2 Investigating the prevalence of and relationships between public perceptions
•Quantitative online survey (N=359)

4. Drivers
ice-melt
thermal expansion
tides
storms
waves
Physical impacts
flooding
salt water intrusion
erosion
ecological change
Socio-economic impacts damage to homes and property inconvenience impacts on infrastructure impacts on business and industry
Vulnerability geology, hydrology, demographics, adaptation

5. Some key findings
•Salience
•Knowledge
•Concern
•Blame, responsibility, self-efficacy and trust

6. “What comes to mind when I say ‘Severn Estuary’?”
mud
tides
bridges
Severn barrage
sailing
Severn bore
development
landscape

7. “What are the main issues facing the Severn Estuary?”
pollution
alternative energy
Severn barrage
ports
nuclear power
development
shipping
Severn bridge toll
decline in old traditions and industries
sea-level change
global warming
a huge wave
erosion
managed realignment
flooding

8. Informedness
Self-reported informedness of climate change and SLC. Percent responses to bipolar survey question ‘Please indicate which of these opinions you most agree with...’
4.0
2.3
18.1
12.5
47.5
42.8
20.9
27.2
9.6
15.3
I am well informed about climate change (N=354) I am well informed about sea-level change (N=353)
I am not well informed about climate change
I am not well informed about sea-level change

9. Public understandings
•but there are some important differences between public and expert perceptions…
sea levels will rise
this is a risk
ice-melt  sea-level rise  flooding  home and property damage
mitigated by renewable technologies

10. Public
Expert
11% think that sea levels will fall or stay the same by 2100
Sea-levels are projected to rise
51% do not think that thermal expansion causes sea-level rise*
Thermal expansion of water causes a significant proportion of sea-level rise
78% do not think that isostatic subsidence is causing local sea-level rise*
The land around the Severn Estuary is sinking in response to the last glacial, leading to local sea-level rise
60% think that the impacts of sea-level rise will be gradual
Extreme water levels can lead to rapid impacts
12% think that recycling is one of the more effective mitigation measures
The impact of recycling on climate change is small compared to measures such as renewable energy and greener transport
Some key differences between public and expert perceptions of sea-level change *Responses to true/false questions about various statements about sea-level change. These figures include ‘don’t know’ responses as well as responses inconsistent with the expert model.

11. Concern
To what extent are you concerned about future sea-level change on the Severn Estuary? (N=359)
•There was a relatively even split between those who were concerned and not concerned about sea-level change
8.1
40.7
42.9
8.4
0%
20%
40%
60%
80%
100%
not at all concerned
not very concerned
fairly concerned
very concerned

12. Public interview participants blamed sea-level rise on external parties e.g. the rich, corporations, wasteful people, city dwellers, other countries and government.
Blame
Most respondents did not feel it was their responsibility to reduce the causes or impacts of sea-level change, and most felt that it was the government’s responsibility to protect residents from flooding. Participants tended to feel unable to do much about the causes and consequences of sea-level rise.
Responsibility and self-efficacy
The transferral of responsibility to other agencies was accompanied by a critical (dis)trust in these agencies: participants do not tend to feel well protected by flood defences, and in some cases agencies were deemed to be acting unfairly in their response to sea-level change.
Trust

13. Implications
•Findings suggest that improved communications may be necessary: sea- level change was of low salience, most participants did not feel well informed about it, but more than half were fairly concerned or very concerned.
•Communications should include
▫local estimates of sea-level rise
▫processes: thermal expansion, isostatic subsidence
▫socio-economic impacts, especially indirect or lagged impacts of low salience
▫the most effective ways of reducing sea-level rise and its impacts, including personal measures such as flood boards
▫the risks of rapid impacts

14. Thank you
ThomasMJ6@Cardiff.ac.uk