Renaturing Cities and Restoring the Natural Water Cycle Through Green Infrastructure

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I live in Brussels, in Belgium. I am Italian, from southern Italy and my wife is British, from North Wales. Every summer we travel from North to South, South to North to visit our families. Each year, at the end of our holidays, we delight in reflecting on the beautiful diversity of cultures, the stark differences in food and weather, and very diverse approaches to grandparenting of Nonna and Naini & Taidi; our parents. I always enjoy sharing these moments of curiosity and nostalgia with our children. 

This year however something changed. Our discussions were not fun and frivolous, they were serious. They were not centered around favorite meals, the best beaches or my daughter’s annual ice-cream league table. This year the 2500 km between our holiday destinations made very little difference because of one sobering commonality; the climate. This year we saw and felt the negative consequences of climate change on our everyday life. In Italy, temperatures reached 48.8 ℃: a peak that made the country break the European record. There were days where we could literally not set foot outside, the heat in the city intensified by the hot air pumping out of the air-conditioning units on the balconies. Wales recorded its highest ever temperature at 37.1℃, for the sake of comparison I usually like my body warmer on my summer holidays than my in-laws.

Rotterdam, The Netherlands, June 3, 2018: close-up of some of the shops and the public park on top of them at Dakpark.

In July, the European Commission’s Joint Research Centre published the “Drought in Europe - July 2022” report, an assessment of Europe’s drought situation based on the European and Global Drought Observatory. The report showed that a staggering portion of Europe was exposed to warnings (44 per cent of EU+UK) with serious consequences ranging from vegetation stress to severe impacts on farming and the energy sector (for both hydropower generation and the cooling systems of nuclear and thermal plants). The report anticipated that warmer and drier than usual conditions were (and they actually are) likely to occur in the western Euro-Mediterranean region until November 2022 with some precipitation, in many cases associated to thunderstorms, foreseen to alleviate drought conditions while causing damages and further losses. Driving around Brussels in September I can see daily evidence of this in the burnt-out parks and green spaces. 

According to the VI Assessment report of the Intergovernmental Panel on Climate Change (IPCC), it is clear that the climate crisis makes extreme weather events such as floods, storms and heat more frequent and more intense. There is evidence showing that in urban areas hotter heatwaves, longer droughts and heavier precipitation and storms, are connected to each other. The good thing is that we have solutions to mitigate these extreme phenomena. One of these solutions is investment in urban green infrastructure. In cities we must and can restore the natural water cycle with existing technologies. We must renature densely populated areas with blue-green infrastructure on roofs, allowing water infiltration, rainwater harvesting, evapotranspiration, urban heat island effect mitigation and decentralised stormwater management.

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From a policy perspective, the green infrastructure agenda is advancing but decision makers are still too slow to acknowledge the seriousness of the situation. In June the European Commission proposed legally binding urban biodiversity targets within its proposal for a Natural Restoration Law

On September 14 the European Parliament backed with a large majority the proposal of an Energy Efficiency Directive which recognises for the first time in the EU legal framework the water-energy nexus creating space for measures such as green roofs that can save energy required for cooling buildings and through decentralised stormwater management can significantly reduce the energy needed by urban waste water treatment plants to manage runoff and urban flooding. 

Water running over bricks after a heavy rain storm in a city. Storm runoff.

On the same day, the European Parliament passed the motion for the resolution “Consequences of drought, fire, and other extreme weather phenomena: increasing EU's efforts to fight climate change”. This resolution calls on the European Commission to support increased Member States efforts to increase the use of green roof technologies; supports the set up of an EU platform for urban greening; calls on the Commission to set ambitious and specific binding targets for urban biodiversity, nature-based solutions, ecosystem-based approaches and green infrastructure, which would benefit both humans and wildlife and contribute to the overall biodiversity targets; stresses the need to include measures such as a minimum share of green roofs on new buildings, support for urban farming; and increasing the number of green spaces in line with the number of inhabitants. 

We are now looking forward to seeing the publication of the European Commission proposal for the revision of the Urban Waste Water Treatment Directive (UWWTD), a more than 30 years old directive. The UWWTD is due to be published on October 23, 2022. The evaluation preparing the revision of the directive identified the need to improve stormwater overflow and urban run-off. During a phase of public consultation with stakeholders, the European Commission showed interest and asked about these issues. The benefits to deploy green infrastructure including green roofs in urban areas to address these issues are well known. If and how the Commission proposal will approach the problem is still to be seen. 

The policy and regulatory framework are evolving and the awareness of an increasing number of decision makers at European and national level is growing. Given the urgency of the situation, policy makers could do more and should instigate more profound changes in our cities. The next few weeks provide good opportunities to do so. Let’s wait and see. 

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Luigi Petito, 45, father of two, is an expert in European public affairs. He is based in Brussels, cross-roads for international affairs and the European Institutions. In 2019 he was invited to establish and lead the European (EU) Chapter of the World Green Infrastructure Network. Since then, he follows EU policy and regulatory developments related to green infrastructure and advocates for a systematic integration of green infrastructure in urban areas.

Luigi Petito

Luigi Petito, 45, father of two, is an expert in European public affairs. He is based in Brussels, a cross-roads for international affairs and the European Institutions. In 2019 he was invited to establish and lead the EU Chapter of the World Green Infrastructure Network. Since then he has followed policy and regulatory developments related to green infrastructure and advocates for a more systematic integration of green infrastructure in urban areas.
luigi.petito@wgin.org / @WGINetwork

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Water and Plants for Wet, Mesic, or Xeric Green Roofs

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Cooling the Urban Heat Island