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Petteri Taalas

Petteri Taalas: “Change is already taking place and its direction is clear”

The impacts of climate change can already be seen in cities. According to the Secretary-General of the World Meteorological Organization WMO Petteri Taalas, built environment requires standards that ensure the correct approach to facing and combating climate change.

Heatwaves, poor air quality, floods, rising sea levels, storms. When the Secretary-General of the World Meteorological Organization WMO Petteri Taalas lists the impacts of climate change on cities and their residents, he starts with the most essential fact: natural disasters and climate change will have a greater impact in urban environments than in the countryside.Cities do not cool down during heatwaves, as the asphalted surfaces and building masses conserve heat. Extreme heat also deteriorates the air quality, since the air mass and emissions stay in place.“Heatwaves are killing older people and people with illnesses even in Finland. Hot nights in the cities have a significant impact on people’s health. According to the World Health Organization, the amount of people suffering from heatwaves has multiplied by ten in the past 20 years. In recent years, over 200 million people have suffered from extreme heat each year,” Taalas explains.

The floods caused by climate change are generated by increased evaporation in seas. The air is more humid than before, which enables increasingly heavy rains. The impermeable environment in cities poorly absorbs large quantities of water, making them vulnerable to flooding.

Cities must both adapt to and combat climate change

Taalas explains that climate change poses two different challenges to the design and construction of cities and living in them. On the one hand, we must adapt to the challenges of climate change, and on the other hand we must actively combat it.

“Climate change is a slowly progressing phenomenon, meaning that it is a hard one to tackle. However, climate change is already showing signs of itself, since heatwaves and heavy rains that cause flooding are occurring more frequently than before,” Taalas says.

Taalas points out that the past winter and spring in Finland are a good example of how rains have increased and winters become milder. We had heavy rains in the south and extreme amounts of snow in Lapland.

“Finland is located in a region where the impact of climate change will be two to three times higher than the world average. If on a global level, we are talking about a temperature increase of 1.1 °C, it is a matter of 2.5 °C in Finland, even more during the winter season. The change is already taking place and its direction is clear.”

According to Taalas, meeting the 1.5–2 °C target of the Paris Agreement would mean an increase of 3–7 °C degrees in Finnish temperatures, 5–9 °C in winter.

Cooled apartments and protection against rising waters

In the future, cities must be better able to control flood water, i.e. manage stormwater and absorb water in the environment. In Geneva, Switzerland, where Taalas currently lives, green roofs and uncut lawns are already popular. In Toronto, Canada, green roofs are required in buildings of a certain size.

“The ability of built, asphalted and concreted terrain to absorb water is worse than that of undeveloped environment. The question is how much and what kind of vegetation we need to retain in order to control water. We also need new stormwater dimensioning.”

Adaptation is also required by the cooling of buildings and the rise of sea levels. According to Taalas, residential cooling is not only a matter of comfort but also, in the worst case scenario, a matter of life and death. Taalas has an example from 2005 of the rise of sea levels in coastal cities. Then, water levels in Helsinki rose by 1.5 metres, reaching the Market Square.

“Tunnels containing electrical and data networks in Helsinki city centre could afford a water level rise of 1.7 metres. This means that we were only 20 centimetres away from the city centre being without electricity and data communications. We must remember, however, that the Baltic Sea is exceptional in its water levels and amounts.”

Large drivers in energy solutions, transport and construction

In urban development, Taalas feels that the big questions of climate change mitigation are related to energy solutions, transport and construction.

“These are the big questions. Sometimes we toy with the idea of planting trees in cities to act as carbon sinks. In Finland, however, this would not be particularly significant. Forests in the Finnish countryside act as a big carbon sink but are insignificant on a global scale.”

How do we produce energy and heat our homes? Giving up fossil energy would mean decentralised energy production and bio and nuclear energy. Furthermore, circular economy solutions can harness waste energy to good use. Heat recovered from wastewater could heat apartments.

“The variety of energy solutions ranges from solar energy to offshore wind and bio and nuclear energy. The increase in pedestrian and bicycle traffic is a definite trend, and the electrical development of traffic and the implementation of biofuels are also imminent. We need to be able to reduce combustion engine driving,” Taalas lists.

In construction, the essential thing is to support wood construction. Steel and concrete production causes extensive carbon emissions, whereas carbon is stored in the wooden structures.

Where should cities be located in the first place?

The costs of climate change are constantly increasing. Taalas feels that part of the problem is that people have moved into areas that are vulnerable to change. Coastal cities, for example, are typically more vulnerable to the impacts of climate change than cities located inland. On the other hand, low-lying inland areas are vulnerable to floods.

“Pori is one of the most vulnerable cities in Finland, and Copenhagen in Denmark has lately suffered from extreme flooding. We should also consider what kind of areas are suitable for residential use in the first place.”

In the United States, the city of New Orleans has been destroyed roughly every 50 years throughout its history. In 2005, Hurricane Katrina wiped out over half of the city’s buildings.

“If the world was a rational place, we might concur that it is not a suitable location for living. On a global scale, beautiful locations on the coasts are found increasingly attractive, but they also have their downside,” Taalas says.

The direction is correct, but the pace is still slow. This is how Taalas summarises the situation of the built environment. Solutions for the cooling and heating of buildings already exist, for example, but they could be used more frequently.

“A certain conservatism is typical for the construction sector. We have built out of steel, concrete and glass, whereas wood construction is often only an experiment. Land use planners should create standards that lead us in the correct direction.”

Petteri Taalas is a keynote speaker at the Edelläkävijät Tampere customer seminar. The virtual seminar is held on 15 September 2020. Read more about the event (in Finnish) >> 

We need to make our urban structure denser while adapting to the impacts of climate change, such as floods and heatwaves – Read more from our Urban Insight reports:
Neighbourhoods of Tomorrow
Building resilience to a hotter future