High levels of urbanisation characterise the Maltese islands. Urban green areas are a rare sight in Malta, making up only 181.1ha. Such unsustainable urbanisation has led to a number of undesired negative impacts, including flash flooding, an exaggerated urban heat island effect, air and noise pollution, reductions in biodiversity and poor well-being.

Malta has the highest level of soil sealing in Europe, measuring 16.15 per cent in 2015. This means that much of the land is impermeable to the high intensity and short duration rainfall experienced locally during the cooler months, resulting in flash flooding. In addition to this, Malta’s highly urbanised eastern harbour areas also experience an exaggerated urban heat island effect, with temperatures usually being 1.5°C higher than other less urbanised areas. 

Additionally, the percentage of people being exposed to air pollution in Malta is much higher than the European average. In 2017, 26.5 per cent of the Maltese population was exposed to air pollution when compared to the 14 per cent of the European population. While sulfur dioxide (SO2) has seen significant reductions in recent years, particulate matter (PM10) and ozone (O3) concentrations are still high.

Locally, air pollution has been responsible for approximately 576 premature deaths annually. Air pollution not only negatively impacts the well-being of those who live in urban areas but is also a burden on the local economy. In 2012, nitrogen oxide emissions from transportation alone cost the local economy €594,000 in healthcare and crop yield losses, among other things.

Urban life brings along with it higher noise levels. In fact, in 2017, approximately 22.4 per cent of the Maltese population was exposed to higher noise levels from road traffic than that considered safe by WHO.

Over the years, the Maltese islands’ natural environment, which harbours a variety of species, has diminished and become fragmented. While there have been some improvements in the status of particular species, some are in decline, such as the Baroni’s ants nest cricket (Myrmecophilus baronii) and the Maltese door snail (Lampedusa melitensis).

Physical and mental well-being has also been negatively impacted by urban life across Europe. For those living in urban areas, there is an increased risk of developing mental health issues, such as depression and anxiety due to the increased perceived social stress. Urban areas characterised by grey infrastructure do not encourage people to exercise either, leading to higher levels of inactivity and, thus, poor physical well-being.

Air pollution kills 576 people prematurely in Malta- Naomi Vella

Air pollution also contributes to poor physical well-being, whereby the number of premature deaths in Europe is expected to reach anywhere between six and nine billion by 2060. In 2014, air pollution in Europe accounted for large economic costs, including healthcare costs and absenteeism in the workplace, costing €4 and €8 billion, respectively.

Green roofs are one of the many ways in which nature can be introduced within the urban fabric to mitigate the negative impacts associated with unsustainable urbanisation. International as well as local studies, such as the Life Med Green Roof project, have demonstrated the green roofs’ potential in retaining stormwater and delaying any stormwater runoff. In fact, local studies show that green roofs can retain up to 90 per cent of rainfall. 

Green roofs are also effective at mitigating the urban heat island effect through evapotranspiration, decreasing ambient temperatures by 1°C to 4°C, depending on time of day, among other factors.

Green roofs also drastically reduce energy demands for heating and cooling, especially in non-insulated buildings, resulting in moderate energy savings of approximately €0.14/m2 per year for the average household, from cooling only.

Naturally, the introduction of green roofs within the urban environment increases species diversity. Due to its many different layers, a green roof also provides sound insulation. Air quality is also improved, especially through the sequestration of carbon and removal of air pollutants such as ozone, nitrogen dioxide, sulfur dioxide and particulate matter.

While there have been many urban greening initiatives in recent months, it is clear that there are opportunities for improvement, through, for example, the implementation of green roofs within the Maltese residential sector. However, as with any new sustainable building practice, there are barriers to overcome when implementing green roofs within this sector, one of which is financial feasibility.

A financial analysis of an extensive green roof system has demonstrated that, since initial costs are too high to bear by many within the Maltese residential sector at present, their implementation may be encouraged through economically feasible government incentives. After all, can you put a price on better quality sustainable urban living?

Naomi Vella has recently finished reading for a Master of Science in sustainable urban management at Heriot-Watt University, in Edinburgh, Scotland.