Floods are seemingly unavoidable these days. Florida, North Carolina, Nigeria, Tunisia, Mexico, India, Nepal, Vietnam, Poland and Austria are among the places that have experienced flooding in the last month. Those floods should no longer come as much of a surprise. Climate change leads to more frequent and intense rain almost everywhere on the planet, and most infrastructure, from roads and bridges to canals and hydroelectric dams, is simply not built to withstand such extremes.
That’s where Vienna stands out. The floods that have deluged central Europe over the past two weeks caused plenty of disruptions in Lower Austria, including to a newly built train station meant to connect the burgeoning suburbs to the city. But aside from some disruption to Vienna’s otherwise well-functioning subway system, Viennese homes were largely spared. Why? It’s not because Vienna sits on higher ground than the surrounding areas (by and large it does not). The reason the city escaped the worst of the floods is because of human engineering and political foresight dating back to the 1960s, which emerged in response to earlier floods that devastated parts of the city.
The train station that was damaged, which sits to the west of Vienna, was built in 2012 and is itself a sign of the growing problem. Lower Austria’s own flood maps show how the Tullnerfeld suburbs are particularly vulnerable to flooding, yet thousands of new single-family homes have been built in suburban areas surrounding the station. Continued Bodenversiegelung – German for “soil sealing”, where green fields are concreted over for development – all but ensure that flooding is going to get worse for years to come.
One problem is that the yardstick for sensible flood protection is changing fast as the climate crisis accelerates. In the 20th century, a “100-year” flood was so-called because it might have only happened once in 100 years. Now, such extreme events are more regular. A months-long cleanup once a century may be a risk worth taking, but doing the same clean-up every decade, or even once a year, is not. All that makes Vienna’s own flood protection all the more impressive. Built along the Danube, Vienna had endured its share of floods over the years. The largest in recorded history happened in 1501, when the Danube carried about 20 times as much water towards Vienna than in an average year. The biggest flood in the last century was in 1954, and devastated parts of the city. Years of political handwringing followed about what to do to protect it.
In 1969, Vienna’s city council voted to build what has since become known as the Donauinsel, a 21km-long island in the middle of the Danube. The island effectively created a dam and a relief channel north of central Vienna that was able to hold enough water to help protect the city against the kind of flood that occurred in 1501. So far, it has held up its promise.
Then there are the wider political questions raised by Vienna’s experience. Initially, when parliament voted to build the Donauinsel, Austria’s conservative People’s party (ÖVP) opposed the new island on the basis that Vienna had more “urgent” tasks to solve. Vienna’s conservatives might since have come around to seeing the error in their opposition. But the national party is as opposed to climate action as it has always been, and is now only surpassed in its zealotry by the far-right Freedom party. The latter just emerged as the strongest force in Austria’s parliamentary elections. And the right’s opposition to climate action, of course, extends well beyond Austria.
There are ample steps cities the world over must take to protect themselves against the climate crisis. Building “1,000-year” flood protections is only the beginning. In a world where fossil fuel emissions anywhere can lead to a drastic rise in Arctic lightning, where Arctic “zombie viruses” could spark pandemics and where Canadian wildfire smoke turns New York City’s skies orange, adapting to climate change goes well beyond building dams.
Yet a dam – the simple piece of engineering that has so far protected Vienna – has numerous benefits. Dams can double as a low-carbon source for hydropower (Vienna’s dam doesn’t produce any electricity, although Austria gets two thirds of its own electricity from hydropower, accounting for most of its low-carbon generation). There are plenty of other steps that are triple-wins: good for cutting greenhouse-gas emissions, adapting to climate change and the economy. Particularly in Britain, this could start with insulating homes against the elements, to cut down on heating and cooling costs and associated emissions.
It also extends to smart spatial planning. It seems obvious that we should cease building more suburban houses on floodplains – or more suburban houses in the first place, for that matter. After all, it is far easier to protect homes within a city such as Vienna than the sprawling enclaves surrounding the city, and dense urban neighbourhoods allow for much lower-carbon living than suburban subdivisions. That’s a win for flood protection, and a win for cutting carbon emissions. Vienna frequently ranks among the world’s most livable cities for good reason. Protection against climatic extremes does not yet figure into these rankings. It should, and Vienna would once again come out on top.
Gernot Wagner is a climate economist at Columbia Business School. He is a member of the scientific advisory board of the Wiener Klimarat, Vienna’s climate council
• This article was amended on 2 October 2024 to correct the caption to a picture showing the Donauinsel.
