Biodiversity for the cities of the future
Biodiversity for the cities of the future
Goal 11 of Agenda 2030 sets the following objective by this date: Make cities and human settlements inclusive, safe, resilient and sustainable.
In particular, objective 11.4 is aimed at “Strengthening efforts to protect and safeguard the world’s cultural and natural heritage”.
For the mitigation of emissions, the fight against global warming and for the better living conditions of citizens, biodiversity will play an important role in the cities of the future; but current models of urban development often reinforce the disconnect between man and nature.
For this reason, the cities of the future (which is already relevant for Agenda 2030) will have to invest in the conservation and expansion of urban natural ecosystems.
Cities around the world are responsible for around 75% of global greenhouse gas (GHG) emissions: transport, buildings, energy and waste management are among the largest contributors to emissions. Cities, therefore, have a fundamental task to carry out in the fight against climate change and in the global effort to achieve the goal of zero-emission generation.
Even more so because today cities around the world are increasingly suffering the effects of climate change which generates periods of drought, rising sea levels, heat waves, landslides and strong storms; in fact it is estimated that at least 130 port cities with more than one million inhabitants will be affected by coastal flooding and the billion people in informal urban settlements are particularly at risk.
Many cities and communities around the world are already taking steps to build climate resilience and identify effective pathways to reduce greenhouse gas emissions.
A study carried out by McKinsey’s “Thriving amid turbulence: Imagining the cities of the future, 2018” finds that out of 2,600 cities analyzed globally, approximately two-thirds are subject to three types of resource stress:
– Chronic or persistent stress on water, energy and food resources, endemic in some parts of the world, is spreading rapidly. By 2030, water demand is expected to dramatically exceed supply in several cities in India, China, Africa and the Americas. By 2025, many cities in the developing world are also likely to suffer from insufficient energy supplies, due to an expected increase in demand, as well as low access to electricity
– Acute. This type of stress results from exposure to weather events and is concentrated in Asian cities and coastal cities in the Americas. In particular, coastal China is at risk of floods and hurricanes, while northern India is vulnerable to floods and droughts. Latin America’s Pacific coast is exposed to flooding, and the coastal United States faces both hurricanes and floods
– Social. Social stress can result from poor governance, excessively rapid urbanization, unequal distribution of wealth and youth unemployment.
To reverse this situation, cities must plan a series of changes which we can summarize as follows:
– Reprogram urban space;
– Create new green infrastructure in every city;
– Develop a new generation of water management tools;
– Plan a new mobility system based on bicycles, feet and public mobility;
– Develop new heating systems based only on electricity;
– Develop a sharing city of goods;
– Enhance mobility on demand;
– Go back to redesigning the city to promote social inclusion without being subjected to projects anymore;
– Start sustainable urban agriculture (social gardens and more).
In this contribution we will focus on the point: creating new green infrastructures in every city.
In fact, in addition to all the possible technological innovations that could be introduced in the cities of the future, biodiversity plays an important role; but current models of urban development often undermine biodiversity and reinforce the disconnect between man and nature.
Most cities contribute largely to land use change, climate change, nitrogen deposition and the introduction of invasive species, which then lead to biodiversity loss.
The objectives of Agenda 2030, and the constitutional reforms of many countries around the world, on the conservation and protection of nature, require us to invest instead in the conservation of urban natural ecosystems to reduce air pollution, prevent floods and adapt to climate changes.
According to the study “Biodiversity and Health in the Urban Environment”, regarding human health, there is a relatively large literature that identifies various links between urban biodiversity and physical health.
A direct mechanism for the beneficial role of biodiversity on human health is associated with the so-called microbiome biodiversity hypothesis. Symbiotic microbes within the human microbiome help explain the healthy development of the immune system and the healthy functioning of the digestive system. The diversity of an individual’s microbiome is strongly related to their lifestyle, environment and exposure characteristics. People living in urban areas tend to have fewer opportunities to come into contact with beneficial microorganisms whether through diet, respiratory, or skin exposure routes.
Regarding social aspects, environments rich in biodiversity, such as neighborhoods with more trees, can provide an environment for social interaction with others, which probably has a positive aspect towards social cohesion.
Finally, regarding mental health, there is some evidence that species richness of plants or animals may have a positive association with mental health and well-being.
To carry out this reconversion, cities must adopt 7 principles:
– The first principle is to identify and protect areas of high biodiversity (both current and potential) in and around cities;
– The second principle is to maintain or re-establish connectivity between habitat areas to allow the movement of animals and the propagules of fungi and plants;
– The third principle is to build ecological features that can provide habitat for a range of plant and animal species;
– Cycles: the management of biogeochemical cycles at a local scale to improve biodiversity in urban environments;
– Biological interactions including competition for resources, symbiosis, herbivory, predation, pollination and parasitism are important processes that shape the biodiversity of a given place;
– New planning to modify current design practices and standards by incorporating ecological knowledge and evidence to help mitigate the impacts associated with the hostility of built structures;
– New ecological communities and new ecosystems characterized by the presence of new combinations of native and exotic species, without historical analogues.
However, we note, from some studies carried out in various cities around the world and in the policies of various countries, that the objectives towards this transition are still vague, poorly correlated and, unfortunately, still linked to a lack of awareness on the topic.
Just think of what you notice in many Italian cities, namely:
– poor management of public green areas, often with the elimination of previously inserted vegetation, with unjustifiable practices of pollarding trees, with further consumption of soil instead of its recovery, etc.
Evidently there is a lack of a political class that is sufficiently aware of the negative social, ecological and economic relations linked to this reverse trend compared to what is indicated by Agenda 2030.
The PNRR itself, with its calls for proposals, does not seem to outline a clear objective on urban biodiversity, risking squandering public funds and defeating the reason for its establishment.
Furthermore, outside of the National Recovery and Resilience Plan, many administrations continue, with the few funds available, to adopt measures that are insufficient if not, as mentioned, even against the trend.
Yet when faced with official data, released by various national and international agencies or by various scientific meta-analyses, it is extremely clear that we are faced with an ecological catastrophe without precedent in the history of the planet.
Approximately 25% of the 93,579 species for which conservation status is assessed are currently threatened with extinction – that is, listed in the IUCN (International Union for Conservation of Nature) Red List as vulnerable, endangered or critically endangered). The following are threatened globally: 41% of amphibian species, 13% of bird species, 7% of bony fish species, 25% of mammal species and 19% of reptile species (Report Ipbes 2019). Based on the IUCN Red Lists for Europe (the region with the best data), it is also estimated that around 10% of insect species are at risk of extinction. In Europe, 9.2% of bee species, 8.6% of butterflies and 17.9% of saproxylic beetles are threatened with regional extinction. The same IPBES Report (2019) reports a situation that is no better for plants. At risk are 36% of dicots, 17% of monocots, 40% of gymnosperms and 16% of pteridophytes.
Which, precisely if we want to look at the thing from the aspect that is most congenial to this crumbling civilization, that is, in money, is a real bankruptcy.
In fact, as stated recently by former IPCC president Robert Watson, “The loss of biodiversity causes damages amounting to 145 thousand billion a year.”
A value that should inconvenience the national and global Courts of Auditors to reject all policies and investments that are heading towards social and ecological catastrophe.
Before entering politics we should perhaps take an ethical oath preceded by a long process of raising awareness and forming consciences.
Guido Bissanti