Nature in the City – an adaptable tool to cope with future climate change
Future Cities Insight #1 Nature in the City – an adaptable tool to cope with future climate change
In urban communities across the world people are drawn to each other to share experiences, to exchange goods and services, to gain inspiration, to work or for social interaction. Our cities stand for hope and opportunities.
However, there are many indications that we are moving towards an increasingly extreme climate with a future consisting of extreme heat, prolonged drought and severe weather. Extreme heat, in addition to our increased energy consumption, can lead to serious implications for our health. The consequences of climate change are set to continue to hit our cities hard and therefore an holistic approach, responding to the complexities of our cities, is required to combat these risks – what we plan for today’s cities must work tomorrow, for the cities of the future and for forthcoming generations.
Our densified cities need their nature, now more than ever. A large part of today’s urban planning is already underpinned by the knowledge of how greenery relates to ecosystems, such as increasing biodiversity, improving air quality, reducing carbon dioxide levels and contributing to the important social and recreational values for people in cities. Whilst these underpinnings need to develop further, we can however now actively and strategically use nature to buffer against the predicted extreme climate and to create sustainable cities.
In the cities of the future, there will be an increased need for climate regulation to balance what is known as the Urban heat island effect, which occurs when heat is stored in a city’s densified areas in hard elements such as buildings, parking areas and roads. It is apparent even today that these areas can differ by several degrees when compared to larger green areas in the city, especially at night where they cool at a slower rate.
Our urban forests, parks, trees and vegetation play a key combined role in regulating the city’s temperature and thus need to be planned, implemented and retained through the various overriding green strategies. We need to see a re-prioritisation of the city’s surfaces, with a smaller proportion given over to hard areas that absorb heat and instead begin using a brighter and more reflective palette for building facades, roofs and ground materials in addition to an increase in permeable materials and green areas. On a smaller scale, shade needs to be provided in our cities to create environments which cater for people to pause, meet and play. The planting of new trees and creation of smaller parks can significantly improve conditions in our cities, and when partnered with a palette of robust, varied and flexible vegetation help to respond to the challenges posed towards our urban environments. Thus, the measures mentioned above provide an important base for reducing the Urban heat island effect.
Urban greenery also contributes to an increased level of water absorption in the case of heavy rain. For example, a larger tree can ‘drink’ several hundred litres a day. Actively leading rainfall to an urban environment’s low-lying vegetated areas is another way to successfully mimic nature and therefore create an more resilient city.
Together, we need to further understand and continue to explore the valuable opportunities that nature provides for our cities. Urban vegetation is fundamental for dealing with the problems and challenges we have created in our cities. We owe it to the cities of tomorrow.
AFRY, together with Växjö kommun, are developing the new area of Bäckaslöv. Robust tree avenues, sustainable urban drainage solutions situated at low points caterering for 100 year’s rain and a wide esplanade street section are examples of how nature can be used to buffer against extreme weather.
Helena Paulsson, Emma Ekdahl and Fanny Rading-Heyman