FCERM.net Heriot-Watt University, 19th June 2014
A ‘Reality’ approach to flood risk
management research
Edmund Penning-Rowsell
Member: Flood Hazard Research Centre http://www.fhrc.mdx.ac.uk
Member: Oxford Water Security Network www.water.ox.ac.uk
Editor: Environmental Hazards (Taylor and Francis) http://mc.manuscriptcentral.com/ehaz
Copyright (text) FHRC
A ‘Reality’ approach to flood risk
management research
Realism in Wikipedia:
A concern for fact or reality and rejection of the impractical and
visionary (i.e. the idealistic or utopian)
In its Kantian sense, realism is contrasted with idealism. In a
contemporary sense, realism is contrasted with anti-realism,
primarily in the philosophy of science.
Scientific realism is, at the most general level, the view that the
world described by science is the real world, as it is,
independent of what we might take it to be.
Realism (or naturalism) in the arts is the attempt to represent
subject matter truthfully, without artificiality and avoiding artistic
conventions, implausible, exotic and supernatural elements.
‘Realism’ No. 1: Flood warnings. The reality is
that there are many ‘alerts’ and ‘warnings’, but research
continues to show that people at risk continue to
consider they are not warned well enough, or even at all.
Priest S J, Parker D J, Tapsell S M 2011. Modelling the damage reducing
effects of flood warnings using European cases, Environmental Hazards,
10, 2, 101-120
‘Realism’ No. 2: Flood insurance. The reality is
that Flood insurance is widely available – internationally
unique - but (a) the poor have far less cover and (b) the
main beneficiaries of flood ‘defence’ expenditure are the
shareholders of insurance companies.
Penning-Rowsell, E.C. and Pardoe, J. (2012) Who benefits and who
loses from flood risk reduction? Environment and Planning ‘C’, 30, 448466. doi:10.1068/c10208..
‘Realism’ No. 3: Flood ‘victims’. The reality of
flood victim’s experiences need careful attention, but we
also must be aware that victims’ pressure on politicians
and others can seriously distort decision making.
Harries, T. and Penning-Rowsell, E.C. (2010) Victim pressure, institutional inertia and climate
change adaptation: the case of flood risk. Global Environmental Change 21(1) 188-97, DOI:
10.1016/j.gloenvcha.2010.09.002
‘Realism’ No. 4: Spatial planning. The reality is
that – in a small and crowded island - there will always
be development in areas at risk of flooding. Such
decisions need to be properly understood.
Pardoe, J., Penning-Rowsell, E.C. and Tunstall, S. (2011) Floodplain conflicts: regulation and
negotiation, Natural Hazards and Earth System Sciences, 11, 2889–2902.
DOI:10.5194/nhess-11-2889-2011
‘Realism’ No. 5: Risk assessment. The reality
is ….
1.
2.
3.
4.
5.
6.
First review: Three anonymous peer
reviewers (September 2012)
The results presented at the Rotterdam
2012 conference (November)
Second review: Two anonymous
reviewers plus Prof. Paul Bates (Jan
2013)
Third review: Prof. Paul Bates (August
2013)
The results discussed with senior EA staff
(2013): Ian Meadowcroft; Stefan Laeger;
Ronan Palmer
Paper accepted January 2014 and
published on-line 20th March 2014
A ‘realist’ approach to the extent of flood risk* in
England and Wales
Edmund C. Penning-Rowsell
Flood Hazard Research Centre, Middlesex University, London, UK
Why is a national economic**
assessment of flood risk
important?
• It informs the whole UK
discourse and debate about
floods, risk management and
climate change
• It therefore affects policy to a
significant extent
• It also affects capital and
revenue budgets for flood risk
management
* Fluvial and coastal ONLY here
** Not financial losses
(‘Rotterdam 2012, plus’)
Who said annual average flood damage was
approximately £1bn in England and Wales??
Document
Foresight Future
Flooding (Ex. Sum.)
Foresight Future
Flooding (Volume 1)
Flooding in England
(the EA)
£1bn
Quotation
“…even with the present flood defences, we experience an (annual) average of
£1,400 million of damage (£1,040 in England and Wales).”
“Within the NAFRA 2002 study it was estimated that the annual average
economic damage due to flooding is, on average, in the order of £1billion pa”.
“The expected annual damages to residential and non-residential properties in
England at risk of flooding from rivers and the sea is estimated at more than
£1 billion.”
“The annual costs of flood damage in England are estimated to be at least
£1.1 billion”.
Flood risk
management in
England (NAO)
CCRA, main document “Present day Expected Annual Damage (EAD) to residential and nonresidential
(flooding)
properties from tidal or river flooding is of the order of £1.2 billion in England
and Wales. The EAD is an estimate of the average annual damage to property
and contents. The total damage could be much higher if other assets and
indirect and intangible losses are included.”
The EA’s Long Term
“The average annual cost of damage from flooding in England is estimated at
Investment Strategy
more than £1 billion. These costs are borne by householders, businesses,
central and local government and others including insurance companies”.
CCRA Executive
“Annual damage to UK properties due to flooding from rivers and the sea
Summary
currently totals around £1.3billion (and) is projected to rise to between
£2.1billion and £12 billion by the 2080s.”.
CCRA: Floods and
“On average, annual damage to properties and their contents due to river and
Coastal Erosion,
tidal flooding in the UK currently totals around £1.3billion”
Sector Perspective
GoS
2004
Evans
2004
EA
2009
NAO
2011
Defra
2011
EA
2011
Defra
2012b
Defra
2012b
(Other than terrorism & other malicious attacks)
Coastal
flooding
Inland
flooding
2010
2013
2010
2013
From ‘NAAR’ in 2000/2001 to ‘NAFRA’ 2008 (£ billions)
….. modelling flood risk to gauge AAD
Coverage
Damages p.a.
(England)
Damages p.a.
(Wales)
Damages p.a.
(total England
and Wales
(£bn)
Properties
affected
(England)
Properties
affected
(Wales)
Properties
affected (total
England and
Wales)
NAAR
2000
NAAR
2001
RASP
2002
NAFRA
2004
NAFRA
2005
NAFRA
NAFRA NAFRA 2008(B)
2006
2008(A)
England
England and
Wales
England
and Wales
England
and Wales
England
and Wales
England
and Wales
1.149
But
without any
significant calibration
0.262
0.626
0.801
1,797
England and Wales
1,909
1.060
1,741
Results
not
available
2.332*
Results
not
2,218++
available
1.411
5.136
1.281
2,137
2,400
2,400
169
225
225
2,306
2,625
2,625
…. all accompanied by myriad changes in method and data, but with the same aim
NAAR = National Assessment of Risk.
NAFRA = National Flood Risk Assessment
From ‘NAAR’ in 2000/2001 to ‘NAFRA’ 2008 (£ billions)
….. modelling
to gauge
AAD unstable and unreliable
Conclusion
No. flood
1: therisk
model(s)
appears
Damages p.a.
(England)
Damages p.a.
(Wales)
Damages p.a.
(total England
and Wales
(£bn)
Properties
affected
(England)
Properties
affected
(Wales)
Properties
affected (total
England and
Wales)
NAAR
2001
RASP
2002
NAFRA
2004
NAFRA
2005
NAFRA
NAFRA NAFRA 2008(B)
2006
2008(A)
England
England and
Wales
England
and Wales
England
and Wales
England
and Wales
England
and Wales
0.626
1,797
New flood
0.262spreading model
5
0.801
4
England and Wales
1.149
6
Annual average flood
damage (£billions)
Coverage
NAAR
2000
1.411
5.136
3
2,137
2,400Based
2,400
2
169
on the
WAAD
225method225
1
1,909
0
1.060
Results
not
available
c. £1bn
1,741
NAAR
2000
2.332*
Results
not
2,218++
available
NAAR
2001
RASP
2002
NAFRA
2004
NAFRA
2005
2,306
NAFRA
2006
2,625
1.281
2,625
NAFRA NAFRA
2008(A) 2008(B)
…. all accompanied by myriad changes in method and data, but with the same aim
Doubts about
coastal flood
risk: Foresight
2004 (The only
mapped RASP
result)
Doubts about
coastal flood
risk: Foresight
2004 (The only
mapped RASP
result)
24m
23m
£10 millions
annual average
damage??
Most of Blackpool is well above current
extreme sea levels if defences are breached
14m
9m
Doubts about
all flood risk:
The IBM
analysis (2006)
They concluded that
“the NAFRA model
over-states the
exposure of the UK
economy (to flood
losses)” (IBM, 2006, 1).
And that this
conclusion “is
supported by the views
of the relevant experts
within Defra and the
EA who, from the
outset of this (IBM)
project, noted that the
NAFRA predictions
seemed high” (IBM,
Conclusion No. 2: some RASP/NAFRA predictions look
badly
2006,
2). exaggerated
The flood damage record:
What have been the historical damage values?
Date
Economic
losses at 2010
values
1947
1953
2000
2007
£0.45bn*
£5bn
£0.79bn+
£3.2bn
How can the annual average be
c. £1bn if there have only been
two (maybe three) floods since
1894 with losses greater than
that value ?
* £12m at 1947/8 prices (the £0.45bn may well be too low); + 2000 prices
The flood damage record:
ABI data on flood insurance claims (£ billions)
0.8
From the ABI Press
Release of Nov. 2010
we get an inflation
adjusted average for
the period 1990-2009
of just
0.6
£0.226bn
1.2
1
0.4
0.2
£0.272bn
0
The simple average (£0.226bn) has
been up-rated by 20% to reflect
less than compete insurance
penetration (c. 90%) and an
element for underinsurance
The flood damage record:
Environment Agency data on the number of
houses flooded
60,000
50,000
40,000
30,000
20,000
10,000
0
The houses > total AAD is factored by the proportion of 2007 losses
attributable to the residential sector, adjusted to economic values
At an average of
£30,000 per event,
this gives a
grossed-up
(economic) AAD of
£0.261 bn
The flood damage potential:
London’s flood risk (£ billions)
£0.70
£0.60
AAD
£0.50
£0.40
£0.30
NAFRA value
for the TE2100
area + all the
Thames region:
£0.66bn
TE2100
value:
£0.07bn
£0.20
£0.10
£0.00
EA Thames TE2100 non- TE2100 nonTotal
TE2100 area Thames area
region
Thames
Thames
Thames
AAD
outside
areas:
areas:
Region plus
TE2100 area
Southern
Anglian
all the
(50%)
(50%)
TE2100 area
Implied AAD in
the rest of the
Thames region
of £0.59bn: This
is simply not
credible
‘Reversing’ the WAAD analysis: What event losses
are ‘needed’ to get to the ‘target’ AAD of £1bn?
18
16
Eight times the huge
2007 losses of £1.84bn
Residential flood losses, 100-year event
Flood event losses (£bn)
14
Residential flood losses, 50-year event
12
10
Residential flood losses, 25 year event
8
6
WAAD =
4
2
0
SOP 25 years
SOP 10 years
c. £0.38bn
SOP 25 years
SOP 10 years
SOP 25 years
c. £0.25bn
National residential AAD 'targets' at the national SOPs above
SOP 10 years
c. £0.10bn
Weighted
Annual
Average
Damages
If residential AAD is £0.38bn (to get a total AAD of £1bn), these are the event losses that are
needed for the 100- and 50-year events, assuming a ‘national’ mean SOP of 1:10 and 1:25 years
Summary results: Not £1bn+ but less than a
third of that (averages = £0.26bn to £0.30bn)
Sources of data
Environment Agency NAFRA 2008
(adjusted by Area teams)
National Audit Office (2011)
EA residential property numbers
flooded (Harmar, 2011), grossed up
ABI press release (ABI, 2010) covering
1990-2009
ABI claims average 1998-2009
IBM risk profile (adjusted NAFRA model
to historic data)
‘Reversing’ WAAD calculations
Simple averages of items in bold (2
significant figures only)
Annual average loss [£bn]: financial
values
Annual average loss [£bn]:
economic values
N/A
1.281
N/A
1.1
0.491
0.261
0.360
0.192
0.606
*
0.268
From residential-only figure of
From residential-only figure of
0.272
0.141
N/A
0.500
N/A
0.263
0.49
0.25 [0.26*]
0.30
with the NAFRA-informed IBM
result included
* Corrected in the Circulation Note to 0.322 and 0.26 to allow for insurance penetration
Counter-arguments
Conclusion No. 4: Counterarguments are at best weak
and at worst misinformed
£1bn?
You are ignoring climate change
Well, we cannot detect ANY ‘signal’ on rivers such as the Thames of
increasing flood flows and hence higher losses now to affect current AAD
Current floods are likely to be more damaging than floods 20-50 years ago, so
you cannot use data from the past (e.g. 1947 and 1953)
Yes: a good point BUT there has also been huge investment over that
period that should have drawn down losses!
You are missing the key “intangible” losses
True, but we ARE comparing like with like, as NAFRA ignores these too
You have ignored “surface water flooding” which is a major hazard
True: BUT insurance data include these in claims, so the amount remaining
from claims totals for NAFRA type fluvial/coastal floods is even less
Even a long record misses extremes that add significantly to AAD values
Well, we go back to 1947 and to 1894 (Thames). And Merz et al.’s (2009)
work in Germany shows that only 20% (2%) of AAD is generally attributable
to floods over a 100 (500)-year return period. Floods that are unlikely to
show up in a 50- to 100-year record will never add hugely to AAD.
1.2
0.8
Raw data from ABI
Deflated to economic values + 22%
(see text)
0.6
0.4
0.2
0
*
Penning-Rowsell, E.C. (2014) What do the 2013/14 floods tell us
about overall flood risk in England and Wales? Circulation, 121, 5-6
Caveat: the
ABI does not
represent the
whole market
(c. 82%)
£0.146
1
£0.147
£bn at 2010 prices (except 2011 to 2013/14
which are at prices then ruling)
Up-date
The Circulation* Note’s extension of
economic damages (residential only)
Up-date
Paul Samuel’s analysis of the
Circulation Note’s economic damages
(residential only)
Conclusion No. 4b: Up-dating
for 2013/14 floods, correcting
one small error, and a
changed residential/NRP ratio
does not change the results to
any marked extent
The
2007
flood
Up-dated residential
fraction of damages:
2000 (45.2%); 2007
(37.9%) & 2013/14
(64.9%). Weighted
mean = 41.8%.
Calculated Residential
AAD = £0.144bn
Total ADD
= £0.34bn
£0.25 [0.26*]
£0.30 billion
PS (12.6.2014): “I have played with the data and supposed 2007 would be the highest damage if we had 50 years of record. Assuming
my use of the Gamma function is correct (need to check this), this changes EAD to £144 M from £178 M to give you an idea of the
importance of this particular event in the bigger picture. I have ideas for other ways of exploring sensitivities, we should also explore
some of the temporal and spatial differences of the 2007 flooding to understand the impact of the event”
A ‘realist’ approach to the extent of flood risk in
England and Wales: Conclusions
Conclusion No. 1: the model(s) appears
unstable and unreliable
Conclusion No. 2: some RASP/NAFRA
predictions look badly exaggerated
Conclusion No. 3: The likely AAD is £0.26£0.30bn, not £1.0-£1.3bn
Conclusion No. 4: Counter- arguments are
at best weak and at worst misinformed
Conclusion No. 4b: Up-dating does not
change the results to any marked
extent (maybe to £0.34bn)
Conclusion No. 5: This exaggeration must
not continue; we must be realistic and
honest about the risks that we face
(‘Rotterdam 2012, plus’)
A ‘Reality’ approach to flood risk
management research
1. Assessing risk
2. Flood warnings
3. Flood
insurance
4. Flood victims
5. Spatial
planning
A concern for fact or reality and
rejection of the impractical and
visionary (i.e. the idealistic or
utopian)
Edmund Penning-Rowsell
Member: Flood Hazard Research Centre http://www.fhrc.mdx.ac.uk
Member: Oxford Water Security Network www.water.ox.ac.uk
Editor: Environmental Hazards (Taylor and Francis) http://mc.manuscriptcentral.com/ehaz
Copyright (text) FHRC
FCERM.net Heriot-Watt University, 19th June 2014