Fadri Campell
As the world population is estimated to hit the 10 billion mark in 2050, cities are going to grow larger and larger. One says that 70% of the people will live in cities by 2050. This shows how important the development of sustainable cities is. With mega cities emerging really fast as we’ve seen it in India the main focus is on creating infrastructure for a fast growing population. However some things very often are left out of consideration: nature based infrastructure. Leaving out on nature and the important ecosystem services it provides can confront us with new problems involving the health of the inhabitants and the productivity of the city.
The past was green
History has shown that big cities always emerged in areas where humans had good access to water (e.g. near lakes or rivers), fertile land and were protected from extreme weather events. In these conditions communities could thrive profiting from ecosystem services such as clean water and good air quality (WEF, 2022). With globalization these conditions were not necessary to the growth of cities anymore, because the emerging cities didn’t have to supply themselves anymore. As a result, nature was let behind in the fast growing metropoles. Climate change has brought some problems to these newly built metropoles: air pollution and rising temperatures in the cities have a bad impact on the health of it’s inhabitants. In mega cities such as New Delhi it has come to the point where children can’t go to school anymore for some days in the year, because of untenable air quality (Akanksha Khatri, 2022). Climate change impacts and rising temperatures only tighten these problems. The cities themselves strengthen these effects, because they have a big impact on biodiversity loss due to land degradation in and around cities. Today urban areas make up over 75% of global carbon emissions even though they only make up a small part of the earth’s surface. With climate change advancing, extreme weather events are becoming more common. Flooding has been declared the most common risk in urban areas. Big flooding events not only are a direct threat to the inhabitant’s lives, but also bring big economical risk. Digitalization plays a lead role in this, as private and public infrastructures are increasing in their value a lot. It is estimated that in 2030 capital stock damage due to flooding events is doubled.
Other very big urban risks are droughts, urban heat and poor air quality all of them affect the cities productivity. Accounting for all of these problems, 44% of GDP created in cities is at risk due to loss of biodiversity and natural spaces as we can see in fig. 1. Therefore stabilizing urban centres is an urgent matter for the economy and also for the goal to reach climate change mitigation goals (WEF, 2022).
Figure 1: Estimated disruption of GDP due to loss of biodiversity and nature (WEF, 2022)
The benefits of nature based infrastructure
Investing in nature based infrastructure could lead cities into a more sustainable future and balance economic, sociological and ecological needs again. Green rooftops and walls could lower temperatures in city centers and even help with food production (e.g. Urban Gardening), maybe enabling some sort of self-supply again and spare other lands wich are used for food production. Urban gardening practices can also make our food systems more resilient again (S. Barthel et al., 2013). In Urban Gardening almost every space available in the city is used to grow Food, this strengthens the food supply and can be very important if a drought or other event destroys crops in conventional agriculture. It also shortens the supply chain between producer and consumer. Green areas such as parks or belts of forests could increase air quality and reduce the risk of floods and landslides by increasing the water infiltration rate into the soil during periods of strong rainfall. Planting Trees upstream or restoring mangroves can slow down excess river flows and prevent floods in cities (L. Schipper et al., 2022). Looking at economical risks, investing in nature based infrastructure can be seen as a good insurance.
Parks and green spaces have a high value for recreational purposes, interacting with nature or just going outside is crucial to the mental health of the city’s inhabitants. If the inhabitants of the cities don’t have to go outside of the city to connect with nature, they spare much free time. Another thing that makes local green spaces sustainable are the short distances travelled by the people, if everything is closer to them many emissions created by public or even private transport can be spared.
Investments in nature based infrastructure are sustainable, because they not only restore nature and ecosystems, but also create great economic and social value. By investing in this, a vast amount of jobs can be created in the future. Mostly natural based infrastructure even costs 50% less than grey infrastructure alternatives, but bring significantly more value in because they increase productivity (WEF, 2022). They also bring positive side effects on the environment and recreation of the people. Reforestation of urban and peri-urban watersheds for example not only improve water security in the city, but also conserve wildlife and restore degraded landscapes around the city and create a lot of new jobs (WEF, 2022). These kind of solutions bring great opportunities to all of the three pillars of sustainability and can improve global city centres in the future.
Problems to face
One big problem is that investing in nature based infrastructure can be very costly, this brings socio-economic problems. Studies have shown that high earning neighborhoods more likely contain green areas other than less wealthy parts of cities, thus temperatures are up to 1.5 ° C higher in low-income areas (R.I.McDonald et al., 2021). Therefore it’s harder for less wealthy people to live a healthy life in the city, this is just a new problem in the growing inventory of social injustice. So economic aspects have to be accounted for by the deciding parties (e.g. mayors), to make this right by investing in low-income neighborhoods. Another problem is that the parties involved in the development of city infrastructure either don’t know about ways to invest in nature based infrastructure or don’t have the economic incentives at hand to do so. At this moment only about 0.3% of money that is invested in cities infrastructure is spent on nature based solutions (WEF, 2022).
Take home message
If we want to tackle the big problems of our time such as climate change, hunger or social injustice, we have to invest in sustainable urban areas. To improve live in cities and to maintain a high productivity we have to consider nature based infrastructure as an alternative to existing grey infrastructure. To do so, the leading people have to be informed correctly as to what is possible and sustainable in economical as well as ecological aspects. This is the political part, but people can make an effort on their own by using their private spaces to implement urban gardening or just design them more naturally to cool the city centres.
References
WEF. (2022). BiodiverCities by 2030: Transforming Cities’ Relationship with Nature. World Economic Forum. https://www.weforum.org/reports/biodivercities-by-2030-transforming-cities-relationship-with-nature
Akanksha Khatri. (2022). World view, Message to Mayors: cities need nature. Nature, Vol 601, 20 January 2022
R.I.McDonald et. Al (2021). The tree cover and temperature disparity in US urbanized areas: Quantifying the association with income across 5,723 communities. Robert I. McDonald , Tanushree Biswas, Cedilla Sachar, Ian Housman, Timothy M. Boucher, Deborah Balk, David Nowak, Erica Spotswood, Charlotte K. Stanley, Stefan Leyk (2021). https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0249715
Schipper et al. (2022). Five key points in the IPCC report on climate change impacts and adaptation. L. Schipper, V. Castan Broto, W. Chow. (2022). https://theconversation.com/five-key-points-in-the-ipcc-report-on-climate-change-impacts-and-adaptation-178195
S. Barthel et al. (2013). Food and Green Space in Cities: A Resilience Lends on Gardens and Urban Environmental Movements. S. Barthel, J. Parker, H. Ernstson (2013). https://journals.sagepub.com/doi/full/10.1177/0042098012472744?casa_token=GcW07zyIgUkAAAAA%3ASzsxhZdJXrH5VwQw_fi5szMPJ1cGeX3Ck8Y-RQY9OlarVyOwppf5ox9VFlVvRG_cazhwOtxqbIM