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Rotterdam: Adapting to climate change

Flood events are becoming more frequent and intense in many cities around the world, with coastal cities at river mouths particularly vulnerable to extreme weather and rises in sea level.


This case study is the third in a series, which also includes New York and Vancouver, and looks at the policy and preparedness of cities.

Following on from ICE's State of the Nation report, they are not so much interested in how to build physical / technical solutions, but how policy is developed and resilience is planned and delivered. Rotterdam's intention is to adapt to its considerable climate challenges and to use this to market itself and its businesses as flooding and climate adaptation experts.


Rotterdam, the Netherlands' second city with a population 619,000, is one of the most urbanised parts of the country. It also contains the Port of Rotterdam, which extends over 40km2, and is Europe's largest port.

The Rotterdam municipality covers an area of 326km2 and has a population density of 7,690/km2. Around 80% of the municipality is at or below sea level. As much as 6.7m is below, which is one of the lowest points in the Netherlands.

Rotterdam has lived with the threat and effects of both river and coastal inundation for centuries, including severe flooding in 1953. As a consequence, the city has led the way in developing flood and storm surge defence systems with much of Rotterdam and the surrounding Rijnmond urban conurbation protected by a network of surge barriers, dikes and dams.

However, around 40,000 people in the city live in homes located outside the dikes and therefore have more limited range of protection against sea-level rise.

Due to climate change, Rotterdam now faces a further threat. The predicted sea-level rise is likely to have a significant effect on the city. Moreover, the forecast increasing extremes of precipitation are likely to cause both flash-floods and droughts.

This combined threat has led Rotterdam to be a relatively early adopter in climate resilience planning, but in a way that places as much emphasis on realising opportunities, as minimising risks.


Much of Rotterdam's economic success and development is linked to its location on the agriculturally rich Rhine–Meuse Delta, where the River Maas meets the North Sea, offering shipping links to the Atlantic and inland to Germany, France and as far as Switzerland. However, as the city's setting has provided opportunities, it also represents a threat.

The coastal and tidal-riverside location, combined with relatively high population density, makes Rotterdam vulnerable to climate change-linked extreme weather events - such as storm surges and sea-level rise.

Rotterdam city and the wider Rijnmond area are protected by a series of dikes, dams and surge barriers, much of which was constructed as a response to the 1953 flood that devastated swathes of south west Netherlands, inundating 165,000 hectares of land and killing 1,800 people.

Rotterdam's population has increased relatively slowly, with a growth of around 6% over the past two decades. The city has a lower GDP per capita, economic growth and employment rate than the national average, and is more economically dependent on its port than most comparable cities.

The susceptibility of Rotterdam to flooding is increased as significant parts of its economic infrastructure including power stations, railways and water purification plants are located outside the protective dikes. As a result, there is a greater likelihood of damage and economic losses if flooding were to occur than for many coastal cities.

The climate outlook for Rotterdam for the remainder of the century is not good. The city is in the top ten ranking for most vulnerable cities. The Dutch meteorological office recently modelled scenarios that have shown that climate change could result in sea-level rise as high as 40cm by 2050 and up to 1m by 2100.

Additionally, the Netherlands has seen an increase in annual precipitation of 14% between 1951 and 2013 and this is forecast to continue. As much of this is in the form of short-lived, intense rainfall, it would not only result in a greater likelihood of flooding in lower-lying urban areas such as Rotterdam, it also means there will also be longer periods of no rainfall.

The risk of warmer, drier summers leading to lower river levels may result in pressures on electricity, agriculture and drinking water supplies. However, such drought may also increase flood risk for Rotterdam - many areas of Rotterdam are built on peat which is settling and compacting, increasing subsidence, and further lowering ground in relation to sea level and destabilising dikes.

Policy approach

As might be expected from a country with its topography, the Netherlands has significant experience in developing flood-resilience policies. Initially, these focused solely on flood prevention. The main example was in response to the 1953 floods where a Delta Commission was inaugurated to develop and execute the Deltaplan for developing a series of protective dams, dikes and surge barriers along the coast and its inlets.

More recently, there has been a gradual shift in national policy, incorporating climate change adaptation and mitigation. A series of documents - beginning with a revised National Spatial Strategy in 2006 - noted the potential effects of climate change on the country, particularly around extremes of precipitation and advocated changes to water management.

It also had decentralisation as a core principle, shifting responsibility for spatial development to provinces and municipalities. The 2007 Programme on Climate Adaptation and Spatial Planning outlined the importance of climate-proofing for the Netherlands, noting that "climate change cannot be prevented, even with all the good intentions in the world…the space in the Netherlands must be adapted such that the effects of climate change are 'acceptable'".

For these reasons, and following the recommendation of the City of Rotterdam's International Advisory Board, the city needed to address climate change, and set up the Rotterdam Climate Initiative (RCI) in 2007. RCI is run jointly with the Port Authority, the Rijnmond Environmental Protection Agency (DCMR) and the port and industrial companies' trade association (the Deltalinqs). It has two main goals, one regarding climate change mitigation and the other on adaptation.

The mitigation target is to reduce the city's and port's Co2 emissions by 50% of 1990 levels by 2025. This is accompanied by the slightly more esoteric adaptation goal to make Rotterdam 'climate proof' by the same year. Rotterdam's plan to reduce carbon emissions is based on three areas - energy efficiency, sustainable energy and carbon capture and storage (CCS). At present, mostly due to industry in-and-around the port area, 16% of the Netherlands' carbon emissions are from Rotterdam, despite it having less than 7% of the population.

The policy is to halve emissions from 24mtpa (million tonnes per annum) to 12mpta. The Co2 emissions in Rotterdam in 2013 were 28mpta - slightly lower than in 2012 but still representing a 16% increase on 1990 levels. In part, this is due to increased operations at the Port of Rotterdam, including those associated with the continued construction of the Maasvlakte 2 extension, increasing the port's size by around 20%.

The programme to manage the second target - to be climate-proof by 2025 - is detailed in Rotterdam Climate Proof (RCP) and the Programme on Sustainability and Climate Change. They were published in 2009 and 2010, respectively, and have had series of annual updates.

Here, climate proofing is defined as measures taken "to ensure that each specific area is minimally disrupted by and maximally benefits from climate change". In addition, all spatial development will "structurally take into account the long-term, foreseeable climate change…and is also a pre-requisite for achieving the city's more wide-reaching aims".

The intention is to ensure not only residents safety, but also their perceived safety from extremes of precipitation, water-level fluctuations, drought and heat, and groundwater salinisation.

RCP is based on "three theme-transcending and mutually reinforcing pillars" - knowledge, actions and marketing communication. The pillars show RCI's aim to turn the city's vulnerability to climate change to its advantage by casting itself as a world leader in adaptation strategy and technology. The purpose is for Rotterdam to be, and be seen, as a protected city that has adapted to its challenges through innovation, research and co-operation.

As such, RCP is unusual in climate change adaptation policy in that it not only aims to prevent the damaging affects climate change might have on Rotterdam, but also stresses the benefits such measures can have on the attractiveness of the city and the potential for economic benefits, such as developing a thriving research and climate-adaptation technology sector.

As part of RCP in 2013, RCI published its Climate Change Adaptation Strategy. It details the main methods Rotterdam intends to utilise to achieve a climate-proof city. The priority for outer-dike areas of the city is to 'build with nature', providing flood protection including 'flood-proof' buildings and public areas, and floating buildings. Inside the dikes the emphasis is more on prevention than adaptation. For example, optimising storm-surge barriers and existing dikes, and incorporating new embankments into the fabric of the city.

The objectives of the adaptation strategy are to protect the city and the port against flooding; ensure the city remains attractive, liable and accessible; minimise the effects of extremes of precipitation; raise awareness of climate change; and ensure adaptation strengthens the city economically and enhances its strong delta city image.

In addition to the broad-brush approach of the adaption strategy, there are separate reports covering more specific themes such as water systems, urban climate and infrastructure. These are informed by the Delta Program, a national programme involving central and local government, water boards and social organisations, and Knowledge for Climate - an academic research programme run by Wageningen University and the University of Utrecht. Both are due to be completed in 2015.

As with the preceding RCP document and programme, there was little, if any, public involvement in drawing up the adaptation strategy. Rather, both were reviewed by internal stakeholders and then adopted by the City of Rotterdam Council as the official policy of the municipality.

Policy criticism

A recent study looking at climate change in land-use planning in Rotterdam concluded the concept of resilience had only lately begun to feature in policy-making. Where it does, urban resilience is usually seen in terms of adaptation rather than mitigation (not that the two concepts are necessarily in opposition).

This is perhaps because, as some commentators have argued, gaining public and politicians' support for adaptation measures is easier, particularly in a small country such as the Netherlands where even drastic domestic changes would have little impact on global climate change.

When it comes to municipalities rather than national governments, the focus on adaptation is sensible. Mitigation is mostly related to the reduction of greenhouse gas emissions, which means local governments simply do not have the necessary reach to have any real correcting effect. Nevertheless, many cities, including mid-sized ones such as Rotterdam, have publicly committed to carbon reductions. Rotterdam's policy is to reduce carbon emissions to 50% of 1990 levels by 2025.

The RCI's sustainability monitor annual updates show emissions from the city (including the port) are actually greater than in 1990 and, indeed, are forecast to rise further in the next few years before reducing dramatically as new schemes such as district heating using residual industrial heat come on line. It should be noted this only appears in the full version of the update – the summary version does not mention current lack of progress on 1990 levels, preferring instead to give the more positive contrast with the previous year's emission levels.

While it is accepted that it is difficult for officials to get clear messages across in summary documents and that there is a desire to accentuate the positive, it also appears slightly disingenuous not to make clear the current lack of progress, even if it were expected.

The RCP places importance on developing a climate barometer, which is designed to help assess and describe Rotterdam's "climate resilience performance relative to the ideal situation and in comparison with other cities". Despite being developed, the climate barometer, has not been published but, instead, is used as an internal tool by RCI. While the annual sustainability monitors are public, the non-publication of the climate barometer seems like a missed opportunity to not only demonstrate Rotterdam's progress towards its 2025 goals but also assist other cities to make similar efforts. Moreover, the lack of willingness to share this information would seem to contradict the emphasis placed on developing a sector of the city's economy based on being an adaptation leader through knowledge, action and marketing communication.

With its networks of dams, dikes and surge barriers, Rotterdam has extensive and longstanding experience in adapting to risk of coastal flooding. In the areas outside the protective dikes, the practice is to elevate buildings to be able to withstand a 1:40,000-year flood event. Rotterdam's long history of adaptation to flood threats means that in spite of the threats most residents and business owners have little direct experience of flooding, and, as such, there is little public call for - or involvement in - developing new measures.

Despite the international profile of Rotterdam in developing climate change adaptation technologies and policies, including leading roles in groups such as Connecting Delta Cities and C40, and the praise the city has received, there was no public consultation in drawing up neither RCP nor the Climate Change Adaptation Strategy. It''s a decision which, in part, is attributed to a discerned lack of interest stemming from the ubiquity of flood prevention measures in Rotterdam.

The perceived public attitude may well be the case - studies have demonstrated residents will only begin to take action after they have experienced flooding themselves. Nevertheless, another potential reason of neglecting flood risk could be the paucity of communication - more than half of Rotterdam residents do not know if they are living inside or outside the dikes.

The goal to climate-proof Rotterdam would suggest the aim is to ensure that the city is not affected negatively by climate-related factors such as extremes of precipitation or sea-level rise. However, "proofing" is actually defined as minimising negatives and maximising positives. This is more realistic but, as the minimum and maximum are not determined, it leaves questions around how to assess whether the 2025 goals are reached.

It would be more useful if the RCI defined metrics across the six objective areas to allow clear assessment of progress – doing so would also make it easier to see when lessons can be learned and best practice developed and disseminated and, therefore, help to meet cross-cutting knowledge, action and marketing communication themes.


Adaptation planning is, in many ways, more difficult than building infrastructure - it is equivocal. Traditional infrastructure resilience planning is based on a linear view of reacting to events in an attempt to prevent them happening again. However, with climate change affecting areas in different, often unpredictable, ways, such incremental and predictable responses are becoming less suitable.

In developing their climate change policy, the City of Rotterdam and its partners in the RCI, have chosen to pursue two main policies – to halve carbon emissions by 2015 and climate-proof the city and its port

In a sense, the former - the mitigation element - is more straight-forward, as there are a wide range of technologies and methods available, and their application is well understood. The RCI has chosen to apply a programme of pursuing energy efficiency, sustainable energy and CCS. While progress in reducing emissions is currently negative, RCI maintains this cycle was expected and they remain on-target for 2025.

Whether the mitigation goal is achieved will be clear and can be independently verified. This, however, cannot be said of the adapting, climate-proofing goal to take measures to ensure minimal disruption and maximally benefits from climate change by 2025. There is no definition of minimum and maximum in this context, but even if there was, because it is difficult to measure absence, it would only be known if they had been achieved after a (or a series of) climate change related events.

This said, because the aim of making Rotterdam climate-proof by 2025 is qualitative and aspirational rather than quantitative, it is not necessarily a problem. Particularly in a field such as climate change adaptation, where there are many shifting unknowns, having an inspiring goal can be galvanising and motivating.

RCI has also set out for the city and the port to be a leader in climate change adaptation through knowledge, actions and marketing communication.

Here, there are many innovative developments both in flood defence and 'working with nature'. Nevertheless, there remains a certain vagueness, or at least a lack of dissemination.

Few citizens know of the policy, or the even longstanding adaptation measures (such as dikes) in place, and information on achieving targets is not explicit. Addressing these issues would help ensure Rotterdam's turns its risk into an asset.

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