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

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?

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)

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

Some key findings

• Salience

• Knowledge

• Concern

• Blame, responsibility, self-efficacy and trust

“What comes to mind when I say ‘Severn Estuary’?”

mud tides bridges

Severn barrage sailing Severn

bore

development landscape

“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

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

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

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.

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

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

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

Thank you

ThomasMJ6@Cardiff.ac.uk