Coastal adaptation measures must consider both sea level rise and extreme sea levels

A scientist specialising in coastal risks and climate change at the University of Southampton, UK, has reported that, while our understanding of sea level rise is growing, further information is needed about extreme sea levels—effects due to storm surges, high tides, and waves.

Our understanding of the impact of sea level rise on flood risk is growing. In fact, recent results are quite shocking. For the US coast, Buchanan et al (2017) concluded that events that currently have a one per cent chance of occurrence in any given year (so-called 100 year events) may occur 25 times as often by 2050 under a moderate scenario of climate change, and 40 times as often under a high-end scenario. They also pointed at different impacts of sea level rise on the occurrence of relative frequent (moderate) and rare (extreme) flood events: On the east coast, cities like Charleston or New York will experience a strong increase in the number of moderate events, while a city like Seattle on the west coast will experience a more rapid increase in the number of rare extreme events.

Climate Change Post summarised this study in their article ‘Current once-in-a-hundred-years flood levels along US coastline may occur every few years by 2050’. Similar results were shown in a study by Vitousek et al (2017), summarised in Climate Change Post’s article ‘Just a few cm of sea level rise may double the frequency of coastal flooding’.

Sea level rise, however, is a gradual process that can be anticipated. Extreme sea levels due to storm surges, high tides, and waves, on the other hand, occur randomly and accurate forecasts become only available a few days or hours before the impacts occur. Recent events like Hurricanes Harvey and Irma have revealed how vulnerable and ill-prepared many coastal communities are for such extreme events. Therefore, adequate adaptation has to take into account sea level rise and extreme sea levels as well as the uncertainties inherent to both of them.

Little is known about future extreme sea levels at continental and global scales. In the IPCC assessments, for instance, a lot of information is presented on sea level rise but the information on extreme sea levels is limited. Uncertainties in these extremes are at least as important as uncertainties in projections of sea level rise. Hence, both these contributions to flood risk need to be integrated to fully assess impacts and adaptation needs.

Future changes in storm surges may add to sea level rise or damp the effects of sea level rise. According to a study by Vousdoukas et al (2016) projected storm surge changes strongly vary along Europe’s coastline: An increase in Northern Europe, no change or a slight decrease in the South (summarised in the article ‘Storm surge levels increase along Northern Europe’s coastline’).

Thus, recent studies point at strong impacts of both sea level rise and storm surge on flood frequency, that strongly vary along the US or Europe’s coastline, and the combined effect of which is highly complicated. Clearly, these combined impacts need to be accounted for in coastal management and adaptation plans.

The article first appeared on Climate Change Post and is a digest of a scientific paper by Wahl, 2017. Environmental Research Letters 12.

 
Articles you may be interested in
In Detail
Exploring frontiers in sustainability: Bringing futures literacy to financia...

As part of EIT Climate-KIC’s Long-termism Deep Demonstration, Riyong Kim, Director of Decision Metrics and Finance at EIT Climate-KIC, has co-authored a new report,...

Exploring frontiers in sustainability: Bringing futures literacy to financial services in Ireland and France
Opinion
Long democracies
Dark Matter
Long democracies
Opinion
Long financing in a volatile world
Dark Matter
Long financing in a volatile world
Opinion
Long welfare
Dark Matter
Long welfare
Opinion
Abstracted to entangled organisation
Dark Matter
Abstracted to entangled organisation
Opinion
Persistent things
Dark Matter
Persistent things
Opinion
Persistent selves
Dark Matter
Persistent selves
Opinion
Futures in long-termism
Dark Matter
Futures in long-termism
In our community
Strengthening community ties and supporting each other through the COVID-19 ...
Strengthening community ties and supporting each other through the COVID-19 crisis
Opinion
The Corona canvas: How to deal with the crisis as a founder
Marc Mogalle & Anje Kluth Business Buddies & EIT Climate-KIC
The Corona canvas: How to deal with the crisis as a founder
In The News
Lilium completes funding round worth over €224 million

EIT Climate-KIC supported Lilium, a Munich-based aviation company developing...

Lilium completes funding round worth over €224 million
In The News
TWAICE raises €11 million series A to power internationalisation efforts and...

EIT Climate-KIC supported TWAICE, a Munich-based battery specialist, has...

TWAICE raises €11 million series A to power internationalisation efforts and scaling
In our community
Madrid: A city turning eco-fictions into eco-futures through systems innovat...
Madrid: A city turning eco-fictions into eco-futures through systems innovation
In The News
EIT Community shines on Forbes 30 under 30 Europe list

Eight EIT Climate-KIC innovators are featured in the prestigious...

EIT Community shines on Forbes 30 under 30 Europe list
Opinion
Trees as infrastructure: Part two
Dark Matter
Trees as infrastructure: Part two
Opinion
Trees as infrastructure: Part one
Dark Matter
Trees as infrastructure: Part one
Opinion
Could COVID-19 usher in massive systemic change?
EIT Climate-KIC Italy
Could COVID-19 usher in massive systemic change?
Opinion
Working during corona lockdown: EIT Climate-KIC Italy sets an example
EIT Climate-KIC Italy
Working during corona lockdown: EIT Climate-KIC Italy sets an example
Innovation Spotlight
How to improve building energy performance without up-front capital

Air-conditioning equipment, office furniture, lighting systems and even floor coverings are being leased, so why can’t a...

How to improve building energy performance without up-front capital
In The News
EU Taxonomy shows the way to net zero by 2050

The Technical Expert Group (TEG) on Sustainable Finance has...

EU Taxonomy shows the way to net zero by 2050
In The News
Regine Kreitz new EIT Climate-KIC Director of Marketing and Communications

Regine Kreitz will join EIT Climate-KIC, the European Union’s...

Regine Kreitz new EIT Climate-KIC Director of Marketing and Communications
In The News
KICs tackling water scarcity in Southern Europe

How EIT and KICs are working to address one...

KICs tackling water scarcity in Southern Europe
In The News
EIT Climate-KIC and partners launch Massive Open Online Course on e-waste

EIT Climate-KIC, together with its partners the UN, the...

EIT Climate-KIC and partners launch Massive Open Online Course on e-waste
In The News
Five EIT Climate-KIC innovators featured in Global Cleantech 100

Five EIT Climate-KIC supported innovative ventures included in the...

Five EIT Climate-KIC innovators featured in Global Cleantech 100
In The News
The journey to zero-emissions transport – part three

The transport sector already accounts for a quarter of...

The journey to zero-emissions transport – part three
In The News
The journey to zero-emissions transport – part two

The transport sector already accounts for a quarter of...

The journey to zero-emissions transport – part two
In The News
The journey to zero-emissions transport – part one

The transport sector already accounts for a quarter of...

The journey to zero-emissions transport – part one
In The News
Malaysia and Estonia win Climathon Global Awards at ChangeNOW summit

The city of Penang, Malaysia, and a team of...

Malaysia and Estonia win Climathon Global Awards at ChangeNOW summit
Opinion
Redesigning venture capital (part III): A hypothesis
Dominic Hofstetter Transformation Capital, EIT Climate-KIC
Redesigning venture capital (part III): A hypothesis
Opinion
The Long Time
Beatrice Pembroke & Ella Saltmarshe Co-founders, The Long Time Project
The Long Time