uhi effects and strategies to improve outdoor thermal comfort in dense and old neighbourhoods

Abstract Modelling techniques have received growing attention as a tool to investigate the thermal comfort within a city, on the basis of which decision makers can set-up appropriate mitigation strategies. This research aims at studying the effectiveness of strategies for reducing the urban heat island-associated effects in dense and old neighborhoods considering, in particular, green roofs, cool roofs, cool pavements, green areas and urban renewal actions. Computer simulation was selected as the major methodology in this research; ENVI-met software was used under different scenarios for a case study consisting in an old neighborhood in the city of Avola. The investigation focused on evaluating the efficacy of each strategy for a condition corresponding to a typical summer heat wave. The results highlight that the cool pavements allow relevant improvements at the height of 1.50 m, with a temperature decrease up 1.15°C, whereas the other scenarios, given the relatively high density of the buildings, are able to improve outdoor conditions only at higher elevations. Reported results represent a guideline for the choice of UHI mitigation method that can help stakeholders involved in new urban assessment of old neighborhoods in Mediterranean climate

Energy and the city

<p>Spatial planning should have a key role in creating urban environments that support less energy-intense lifestyles. A wise consideration of energy in urban land use policies should play an important role considering that, in spite of having a land occupation of 2% and accommodating 50% of the world population, cities produce 80% of GHG emissions and consume 80 % of the world’s resources.</p><p>In the building industry, the green economy is already part of the designers’ approach. This has already produced several energy efficient buildings that also feature high architectural quality. Now is the turn of cities to take the same direction in developing the capacity of formulating sounded urban policies. This will contribute to develop adequate new tools for achieving the energy efficiency goal.</p><p>Climate change concern, the dominating environmental paradigm, is permeating the political scenario worldwide, producing a plethora of formal documents. The most recent one is the COP21 agreed in Paris in December 2015, after the failure of the Copenhagen summit in 2009, and formally signed in April 2016 in New York. The challenge for land use planning now is to translate these general commitments into actions that modify planning practices at all levels, from cities to regions.</p><p>In this field, the current situation is extremely varied. EU has issued several documents focussed mainly at building level but also sustainable transports are considered a key issue. However, a further step is needed in order to increase the level of integration among all land use approaches, including the idea of green infrastructure as a key component of any human settlement. (European Commission, 2013). </p><p>The relationship between urbanisation and climate change has become key worldwide but looking at it from a Mediterranean perspective arises some specificities, considering also the political strain that this part of the world is facing. Both Southern Europe and Middle East and North Africa (MENA) countries will face stronger heat waves in the near future (Fischer and Schär, 2001). Their cities, often poorly planned for decades, will be considerably affected by these temperature upsurges.</p><p>A further complexity arises from the fact that the energy approach in land use plans is not direct. Including energy considerations in urban and regional planning is hardly a technological issue. On the contrary, it requires a deep change in the mind-set of urban planners that have to think at the whole city structure wearing the new “energy glasses”.</p><p>It is possible to trace the energy issue in land use planning back to its history. Spatial planning has a long lasting tradition in defining the shape of urban fabric and the layout of buildings, taking into account the role of the sun and the wind. This tradition has evolved from the seminal experiences of modernist planning to the new sustainable districts, recently developed in several countries like Germany, the Netherlands, France and Sweden,  including the ones described by Peter Hall (2014) in his last book.</p><p>But Mediterranean countries have an even longer tradition in building cities and houses that were capable of facing hot temperatures, without any of the electric appliances that are consuming now a considerable share of energy. As part of this long-established tradition, it is worth remembering the inspiring contribution of the Egyptian architect Hassan Fathy. Looking back at the city history is not a mere exercise based on nostalgia. Making greener Mediterranean cities, as they were up to a recent past, is a complex task but it will become unavoidable in order to guarantee forms of sustainable cooling.</p><p>This is especially true in those cities that have grown considerably in the second half of the 20^th century, according to high-density models.</p><p>Urban planning has been also concerned with defining the proper mix of land uses, taking into account the key role of transports. Compact and walkable cites, rich of activities, are naturally energy efficient. The lesson taught by Jane Jacobs in her seminal book <em>Death and Life of Great American Cities</em> remains relevant also assuming the energy approach. More recently, emerging planning themes are including the containment and retrofitting of urban sprawl by integrating transport and land use planning. Applying Transit Oriented Development (Tod) principles can induce a change in mobility choices of inhabitants of this unsustainable form of urban settlement, by giving them more mobility opportunities.</p><p>Land use planning will also play a relevant role in accommodating new forms of distributed sustainable energy production in the urban fabric. The recent 2015 Snapshot of Global Photovoltaic Markets, by the International Energy Agency, confirms that economic incentives, like feed-in tariffs, are not enough to guarantee a stable diffusion of this type of energy production. After the phasing out of this incentives there diffusion of PV, reduces considerably. This is case of Italy that installed only 300 MW of PV systems in 2014, compared to 9,3 GW in 2011, 3,6 GW in 2012 and 1,6 GW in 2013. Integrating energy production in the city as part of urban design will increase the opportunity of making sustainable energy production an inherent feature of the city design, including energy production devices in the city realm and using them for retrofitting poor quality buildings.</p><p>In addition, planning tools have to incorporate incentives aimed at favouring higher energy standards, both for new and existing buildings. The costs of these actions should be covered by planning normative tools. Several techniques, like the Carbon Offset Fund in Great Britain, have been tested but there is a great need of new research in this field, at national and local level, since these tools are not easy to implement without taking into account site-specific norms and approaches. In addition, the exclusive use of the market leverage risks to confine these tools to wealthy communities, excluding the poor ones.</p><p>These new attitudes require not only new planning tools but also a great capacity of devising urban policies capable of involving communities with different cultural backgrounds and planning traditions. A wise mixture of tradition and innovation is central to innovate the urban planning discipline in the direction of sustainability.  A lot of <em>mental energy</em> has to be devoted to the difficult but stimulating objective of improving the energy awareness of our cities.</p

Per citt\ue0 pi\uf9 resilienti : progetto urbano per l\u2019efficienza energetica e i cambiamenti climatici

Il workshop ha esplorato la dimensione progettuale della citt\ue0 resiliente attraverso la rilettura critica di esperienze di pianificazione e di progettazione dello spazio urbano, elaborate in ambito nazionale e internazionale, significative sia sul fronte della mitigazione che dell\u2019adattamento, attraverso un repertorio di buone pratiche riferite a strumenti di pianificazione e progetti di spazi aperti, nella duplice prospettiva della mitigazione e adattamento ai cambiamenti climatici e dell\u2019efficienza energetica delle citt\ue0. In particolare, la sfida per l\u2019efficienza energetica della citt\ue0, che richiede di andare oltre la scala edilizia, obbliga a uno sguardo olistico, attento alla citt\ue0 come luogo dove integrare politiche di riduzione dei consumi energetici e di produzione di energia da fonti rinnovabili. Obiettivo del workshop era la verifica di questa impostazione indagando aspetti e pratiche di pianificazione e progetto che riguardano la mobilit\ue0, le infrastrutture verdi nonch\ue9 forme di compensazione e di incentivazione che fanno leva sui meccanismi di mercato. In questo senso la resilienza \u2013 il successo che l\u2019uso del termine ha nella letteratura disciplinare lo dimostra \u2013 pu\uf2 diventare un paradigma potente, capace di costruire un quadro interpretativo e di sintesi in cui il complesso di progetti e strategie di contrasto e adattamento ai cambiamenti possa collocarsi. Come i lavori dell\u2019atelier hanno efficace- mente mostrato, perch\ue9 questo accada bisogna tuttavia riflettere pi\uf9 e meglio sul senso del termine e sulle sue possibili implicazioni, evitando che esso resti un grande ombrello entro il quale, pi\uf9 o meno tutto pu\uf2 essere facilmente collocato

Gibellina, Salaparuta, Poggioreale and Montevago: about built environment underutilization and possible urban future

Disasters like earthquakes affect dramatically the construction of place identity. Urban settlements generate complex social structures: they are not just scenarios where the functioning of city takes place. ‘Interrupted landscapes’ cannot be merely reconstructed. Post-earthquake reconstruction lies in between community social identity protection and urban planning approaches to renewal or rebuilding. This paper focuses on the four urban centres of Gibellina, Montevago, Salaparuta and Poggioreale that were reconstructed in a different place, after the Belìce earthquake in Western Sicily in 1968. Next to a brief review of planning events that characterized the post-earthquake reconstruction, this paper analyses the built environment in these four settlements with regard to built up volumes, land uses and inhabitants. The most relevant outcome is an impressive underutilization of the reconstructed dwellings and evident trends of depopulation and ageing. Literature and data analysis trigger critical considerations on urban strategies and choices that drove the reconstruction, and long term effects caused by the 1968 event. The case study presented reflects on directions for the revitalisation of these area from a town planning perspective, taking into account the present and future challenges for resident communities and local authorities, facing the risk of progressive abandonment of these settlements

"Passata è la tempesta …”. A land use planning vision for the Italian Mezzogiorno in the post pandemic

The Covid-19 pandemic event can activate a comprehensive reflection on the change of development models, overcoming the current unsustainable ones. Present events in Italy are mainly affecting Northern Regions but also the Southern ones will suffer from economic consequences, related to the pandemic. This is particularly relevant for the marginal areas of the Italian Mezzogiorno. The article highlights issues that are deemed relevant for including inner areas of Italian Southern regions into the process of economic recovery after the pandemic, in order to avoid the deepening of the long lasting North South imbalance, in the light of the growing depopulation of this part of the Country. The focus is on the role of Health Services, Education, Built up Environment and Transports, systems considered as key elements for promoting a well-balanced use of existing territorial assets. The real challenge is to reverse this terrible threat into an opportunity, introducing effective changes into the way we waste our limited planetary resources, especially the territorial ones. In this direction, Southern regions can play a fundamental role for increasing the resilience of the entire nation