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Créditos: CML

Sérgio Barroso coordinated the Metropolitan Climate Change Adaptation Plan for the Lisbon Metropolitan Area. An important document in the management and coordination of measures that, on the one hand, mitigate damage, and on the other, protect from risks these cities that gravitate around the Tagus estuary and its tributaries. During these days of heavy rain and flooding, there has been much-veiled criticism from the mayors of the various municipalities, with mutual accusations. Not everything is true, nor is everything false.

Sergio Barroso
Sérgio Barroso, the coordinator of the Climate Action Plan for the Lisbon Metropolitan Area. Photo: DR

There are many interdependencies, but there is also something that unites all these politicians, in the opinion of the geographer and urban planner director of the Center for Studies and Regional and Urban Development and coordinator of the ClimAdaPT.Local initiative: they are all guided more by the interests and concerns of the moment than by the long term. And that’s why, although there are already some actions that allow minimizing the risks of events like those of these weeks, much remains to be done in adapting the territory to what’s coming. Particularly in riverside areas and in construction in flood plains. And there, the Lisbon area sets a very bad example. 

After all, is the high rainfall and the recent flooding we are experiencing the effect of climate change or not?

Climate change is not measured in one day. It is measured in a series of 30 years. And that’s how you can tell. What we have now are very high rainfall events, but they are not out of the seasonal pattern in the Lisbon Metropolitan Area. What these events tell us is what climate change will be in the future.

In what terms?

We will have events like this with shorter time intervals. What used to occur every 100 years will occur every 50 or 30 years. And this has very big implications. One example: is the commerce in downtown Algés. It is one thing to deal with a flood every 20 years. This has direct costs and others. Insurance companies, for example, and others can make it unaffordable to have commerce in those places.

And I call your attention to one thing: in a climate change scenario, as a result of the rise in the average sea level, the flooding in these low points will be even worse. Where we complain today that we get the high tide, it’s going to be even higher. And all these places are going to be even more affected. Rising waters maximize the results of flooding. So the best way to prepare for climate change is to deal with what we’ve seen in the last few days.

They are a good lesson.

It’s an extraordinary opportunity to see what we have to become more resilient. 

And what would you say is essential?

The most urgent and cheapest measure is to have prevention systems and a higher precautionary structure. We have to have response protocols that are not: kids go to school in the morning and stay home in the afternoon. Or don’t even know. We have to be much more prepared. It is not acceptable that cars are parked in the downtown areas when there is an alert like this. We have to have clear protocols that protect people and their lives. Even if it then becomes unnecessary. And this implies a very big culture and self-protection. And this has to be taught in schools.   

Algés suffered flooding in several streets, and the station tunnel, and caused panic. If the rain is frequent, it can end up increasing costs to such an extent that shopkeepers cannot stand it, argues Sérgio Barroso. Photo: Inês Leote

Imagine that I live in a basement in Alcântara or Algés.

It means that there’s going to have to be a rehousing response of intervention and prevention.

This implies a change of mentality. And when it’s not possible to predict – is it true that the system is so changed that sometimes it’s not possible to predict?

That’s not because the system is so altered – it’s because that’s the way it is. Because our basins are very small. The floods in the Tagus or the Douro can be managed. They are big basins, you manage the dams. In the case of the northern part of AML there is no possibility to have reliable alert mechanisms. They are small basins that fill up very fast. This means that the prevention culture has to be more zealous. 

Have the city councils been incautious? 

I think that globally we all are. There isn’t a culture of concern in Portugal. But it is a path that is being taken. The work is being done. And in Lisbon, I admit that the machine was perhaps not so well prepared for the political transition. I, for example, this week received an alert from civil protection – it means that we are already learning.

Yes, but the way it is written… “Stay tuned”! 

It doesn’t work! It has to be very clear. It has to be: leave your house, don’t leave your house! Things have to be defined in advance and very clearly. 

Cruz quebrada praia jamor oeiras poluição verão turistas
O rio Jamor. Foto: Inês Leote

Right. What about the other measures?

They are more expensive. Reduce the inflow of flows to low points. This involves barriers, retention basins, the tunnels in the Drainage Plan, and de-waterproofing – everything that reduces the inflow of water to these sites.

Third issue: you have to consider that on some of these sites eventually, the first floors have to be vacated. You also have to separate the drainage systems, rainwater, and sewage, so that water doesn’t enter through the pipes. This involves large investments. 

To repeat the question: taking into account that all this is not new, heavy rain and flooding, which we know is a usual risk in the city, that there will be more… Do you feel that the municipalities in the Lisbon area have been very incautious in dealing with the issue?

There are two dimensions of this being incautious. One is that urban planning allows the spreading of artificial areas and flood beds. This is a fact – even more so in the surroundings of the city of Lisbon. As far as the intervention in the water lines is concerned, I wouldn’t say that they do anything. It is insufficient, as we have seen… Now, there are critical points. This has become evident. For example, in the Trancão, in Loures, in downtown Loures. There is no drainage worth a damn – although work has been done in that direction. It is a heavily built-up area in the flood zone. Perhaps we can build dikes, or constructions to protect it… but this is difficult.      

Loures is now an extremely urbanized area – it’s impossible to contain the waters of this estuary, says Sérgio Barroso. Photo: DR

Many of the risks are indeed inter-municipal.

The hydrological risks in the northern part of Lisbon are. The hydrographical basins are practically all inter-municipal. They cover more than one municipality, which means that the response to the problem where flooding occurs is necessarily an inter-municipal intervention. The Algés River starts in Amadora, the Jamor in Sintra. The Trancão starts in Mafra. Where the water is concentrated are small basins, which is why it concentrates so fast, and it is difficult to have forecasting systems.

What can be done? 

Everything that does slow down, slows down the speed of the water that reaches the lower area. 

What accelerates the speed of the water?

Everything that does slow down, slows down the speed of the water that reaches the lower area.

What accelerates the speed of the water? Everything that waterproofs – roads, buildings – increases the amount of water that is there and the speed that it reaches. What slows it down? Retention basins, walls, dams, and ponds, alleviate flooding. 

Are the mayors of the coastal areas right in saying that they are taking on issues that start in the neighboring municipalities?

In theory, yes. But what are the situations? Downtown Cascais – the critical point is within the municipality and is the result of a very large artificialization process since the 1950s, around the town, which caused large floods. Oeiras, a large part of Algés, Miraflores, was brutally artificialized and all the conditions for this were created. Even on the side of Amadora and the Central State. The Portuguese Environment Agency itself is in this canal, on top of the flood bed. In Alcântara, the basin comes from Amadora and Sintra, and it is a case of an improper occupation of a channel. Loures, ditto. Even downtown Lisbon. Much of the surrounding area was built and occupied. Nobody can be free of responsibility.

The municipalities have the will to solve this together – did you notice this when you made the AML Climate Action Plan?

In the elaboration of the plan, there was support. It was a huge process of training technicians from all the municipalities with workshops in the municipalities, a mobilizing process. I felt the will to know the dimensions of the problem. But there are many inconsistencies in these processes.

Is this concern evidenced in the decisions of the municipalities? No! When we were discussing the plan, several projects were being approved and promoted on the Tagus bank: in Lisbon, Algés, Barreiro, and Almada. We have several projects planned for areas highly affected by the rising sea waters. 

The Porto Cruz development is being developed near the mouth of the Jamor River, which has now filled up. Photo: DR

Why? Why haven’t we experienced consequences so catastrophic that they scare us?

Political power reflects the inconsistencies in society as a whole. Contradictory interests: development and sustainability, building and housing needs, and releasing soil. We have contradictory forces here. 

Depending on the issue that is under discussion, politicians take a position. Depending on the circumstances politicians react to concrete problems. Some days they have to defend local commerce, other days they think there can’t be any because of the flood bed. But, for example, with fires…

Yes, there you are, we have already experienced this catastrophe. 

Right, but even so we saw the negative reaction of the mayors when ICNF proposed to make risk cartography! Overall, we don’t have a culture of precaution. You saw people who, when faced with a flood, drove their cars forward. And they stayed there. Land use planning has evolved quite well. You can see that we had no human losses because of the floods. 

That’s because the population has evolved, there aren’t so many shantytowns anymore…

Of course! And climate vulnerability is immediately a socioeconomic vulnerability. One of the things that worries me most in the LMA is the Torrão and Cova do Vapor neighborhoods. Re-housing is a priority because that place is critical and a community with fewer resources lives there.

What is your assessment, after having made the plan for the AML, where we stand in facing the problems of climate change?

The answer to the problem of climate change has two arms: one is called mitigation. We emit fewer greenhouse gases because that causes the problem. The other is that even if we mitigate a lot we are going to live with a changing climate and therefore we have to know how to deal with it.

How are we doing in both?

On the mitigation issue, we are the most ambitious because we have a lot of renewable energies and also Portugal is not a particularly polluting country, due to our industrialization which is not so strong. 

The problem lies in mobility – namely in metropolitan areas, where it is a key factor. I find it difficult that the investment that has been made in the area will be very successful because people are very dispersed in the LMA and it is very difficult to offer public transportation with the quality and efficiency that they are used to with their car. 

On the issues of change what concerns me most is heat waves. It’s what kills more – it’s more invisible, it’s not in the media… We have a great vulnerability in our demography, a building with terrible thermal performance and poorly planned cities in terms of building and with a fragile tree structure that does not allow for the reduction of heat island effects.        

Does it worry more than floods?

Yes, because these events may occur from year to year, but heat waves occur every year. And floods have a more specific location. It’s in that place. And heat waves are more diffuse. You can’t move people out of one place. Maybe the elderly. In other words, it’s a broader problem. Look at the healthcare facilities that are not prepared for cooling systems. In these floods, one person died. In a heat wave, hundreds die. These are the problems of the present.

And those of the future… The people of Lisbon feel that there is no front view on this and there is a lot of politicization. There are things here that should be national emergencies… For example, not building in riverside areas… should be national legislation. 

And there is one thing that people like me who work all over the country noticed: Lisbon is a very bad example of that. It is very difficult for me to impose a restriction in the rest of the country on a risky waterfront, and for people to see that in Lisbon you can build the MAAT, the Champalimaud Foundation, a huge development in Algés… People don’t understand that you can do things in Lisbon and not in Régua, for example. 

And what is the explanation?

It’s because we can’t go ahead with the Tagus estuary management plan. Everything is an exceptional situation and everything is allowed – APL is in charge of the management. And this generates a feeling of disrepute? and injustice. Lisbon had an added obligation here because it is very emblematic. What is done in Lisbon is followed. And it’s like that everywhere. I see this in many meetings with many mayors. 

But this will fall on Lisbon too.

In the future, it will. Surely it will. For example, something that is not yet very evident but in the future will be a gigantic challenge is the rising sea level in the Tagus estuary.

On the coastal front, it is from Cova do Vapor to Fonte da Telha. Because it will sink – the rising waters will be added, with an energetic sea, and fewer sediments than we already have. In the case of the estuary, it doesn’t have this dynamic, but we can have for example situations where the Cascais line is interrupted.    

What is the forecast?

By the end of the century, it’s 80 cm. Now, in a thunderstorm, it is to see what that gives, besides coastal erosion. And then this potentiates the problems of flooding. 

Maybe that’s the point, we don’t feel it yet.

London doesn’t feel it but is already preparing to make dikes on the Thames. But this is not possible on the Tagus. 

What is fundamental to do is not to allow buildings in places that can be underwater. I coordinated the Coastal Zone Management Program for AML and the West. And we established prohibitions on construction. 

Are they being enforced?

Yes, they are. They were carried over to the PDMS (Municipal Master Plans). 

Belem Trafaria Barco Transtejo TST Margem Ferry Eletrico Carro Amolador Bicicleta Mobilidade Plataforma intermodal praia
The ferry boat that makes the route Belém – Porto Brandão – Trafaria – one of the areas most at risk. Photo: Inês Leote


There was a plot planned in Costa da Caparica where the Barbas restaurant used to be in Polis, it was a hotel. We interdicted it. In the camping parks, three large lots were planned for hotels. They were also rejected. They manage to establish rules.

Not in Lisbon. 

Not because the POOC (Coastal Zone Management Plan) ends in the Municipality of Oeiras. And there is no management instrument.  

And Lisbon wants to live closer to the river, it has reconciled. 

But this reconciliation is a little strange because what was foreseen was that there would be open space and gardens, and now more and more it is the privatization of the riverfront. That they don’t find any kind of resistance in the municipalities. 

You can read this article in Portuguese.

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