Mr Appl,

Mr Maier,

Ladies and Gentlemen,

when, at the end of a private trip abroad, I fly back home to Hamburg in the springtime, and if the weather is reasonably good, I have a wonderful view as the plane comes in to land: a big, beautiful, and remarkably green city is spread out beneath me. Isn’t that a sight to double the pleasure of coming home?

And when this view greets me returning from official travel, it makes me happy to be mayor of this city and I dare to think ahead a bit. Let us suppose it is May 2030, and the plane is on its final descént: but now a majority of the roofs in the city centre also display varying shades of green, a pretty sight. From today’s standpoint, in 2013, that would be an unusual colour for a roof.

But in 2030 the mayor also sees sunshades, awnings and garden furniture on the roof terraces where Hamburg residents relax after work. And enjoy unhindered views of an assortment of roofs and roof-top landscapes created by the next-door houses, and of the familiar neighbourhood below. There are many districts in Hamburg that the city’s residents love for their magnificent urban flair and for their greenery and recreational qualities, with green roofs making a crucial contribution.

Ladies and Gentlemen,

that is still a vision, but the aim of our munícipal policy should be to make this image a reality. Hamburg is a green city, and it is to stay green and become even greener - at all levels. And the roofs will play their part.

Hamburg is now a growing city, and has many construction sites. We are building 6,000 apartments a year to create urgently-needed new homes, which have to be affórdable and must remain affordable. As the city grows, we will see its dénsity increase - and we also intend to build a little higher; as the city grows, we must chart a new, innovative course leading to sustainable urban development that conserves resources and is in the interests of our citizens. 

It seems a logical step to focus on the city’s roofs and see them as more than just the part that goes 

on top of a house, regarding them instead as an important, usable reserve of space. 

Bringing Nature Back to Town” is what your congress is about. It could also be a good motto for the green roof strategy which the Senate is to introduce and that is now being prepared for implementation. The green roof strategy aims to transform the way we treat the city’s roofs - by creating roofs

• that contribute to measures to mitigate the consequences of climate change;
• roofs that can be planted in such a way that natural biotopes emerge in places where most people would not have thought it possible;
• roofs that can be used for recreation;
• roofs that are - all in all - truly multi-purpose.

I have asked the government departments responsible to flesh out the details of this concept. The green roof strategy is based on the objectives Hamburg’s climate policies are designed to attain and on goals for sustainable, climate-friendly urban development.

Every resident of Hamburg knows that our metropolis is in a flood-prone área. In the interests of the residents of this dense urban área, Hamburg’s government will have to plan to meet the challenges that - as far as we can tell now - climate change seems likely to bring, and take steps to cope with the effects of heavy rainfall and storms.

We shall optimize our flood defences and take precautions to cope with hot spells in summer - perhaps a problem we would quite like to have at the moment, but heat waves can also have serious consequences for city dwellers. Green roofs will be an important part of the planning. 

Rain water management starts on the roof. With so many different uses competing for space in the growing city, greening existing roofs and putting green roofs on new buildings can be one method to gain more space for rain water control. At the same time we can do something to ease the shortage of space in the city - by reducing the área needed for rain water detention basins and retention systems. 

Green roofs can thus help cut the infrastructure investment costs of, for example, new developments, where it would be possible to reduce the size of drains and storm water detention basins. And they can help to mitigate the impact of intervention in natural surroundings, and aid conservátion measures.

We want to combine building green roofs with saving energy: in new building and refurbishment projects, and in the advancement of renewable energy supplies. And green plants have no problem sharing a roof with photovoltaic arráys and solar thermal panels.

As I said: Green roofs open up spaces atop Hamburg’s houses that can be used for leisure and relaxation, as outdoor areas closer to nature and as places to meet the neighbours.

It is also hoped that the green roof strategy will give further impetus to academic research in Hamburg in the fields of climatólogy and adaptation to climate change. We shall close the gaps in our knowledge about the amounts of water green roofs can detain, depending on the various technical solutions suggested and the weather in Hamburg.

One other point is important: green roofs trap dust and pollútants, they provide a habitat for plants and small creatures - many of them already are city dwellers like us and green roofs increase species divérsity, enhance the network of biotopes and improve the appearance of our city.

Ladies and Gentlemen, 

So, as you see, I have great expectations of green roofs. I wish you had every success with this congress and I am hopeful that the people involved in urban development in Hamburg, in whatever capacity that might be - in politics, government, planning offices or the housing industry - and every one will have gained important insights that take us a step further. Thank you very much. 

The spoken word applies.