Otporni gradovi: Kako se gradovi mogu prilagoditi učincima klimatskih promjena?

Globally we are seeing the catastrophic effects of climate change. With more frequent, more severe and previously unforeseen events, such as wildfires, hurricanes, flooding and drought, the need for resilient cities, and in particular infrastructure to be redesigned and/or rebuilt for climate resilience, could not be more apparent.

Što je otporan grad?

Prema OECD-u, otporni gradovi su gradovi koji imaju sposobnost apsorbiranja, oporavka i pripreme za buduće šokove (ekonomske, ekološke, društvene i institucionalne). Otporni gradovi promoviraju održivi razvoj, blagostanje i uključiv rast.

Resilient Cities are often considered the next chapter in sustainability. With energy and water conservation, we need to be doing more to ensure our cities and structures can withstand a climate event.

Priprema, adaptacija, oporavak

Zašto su nam potrebni?

Ujedinjeni narodi predviđaju da će do 2050. godine 70% svjetske populacije živjeti u gradovima. Uz 60% novih urbanih naselja koja tek treba izgraditi, postoji velika prilika za izgradnju otpornih gradova.

Prema Svjetska zabranak, 4.2 trilijuna dolara moglo bi se uštedjeti ulaganjem u otporniju infrastrukturu. S Program Ujedinjenih naroda za ljudska naseljae forecasting that by 2030, without significant investment to make cities more resilient, natural disasters may cost cities worldwide $314 billion per year and climate change may push up to 77 million more urban residents to poverty. 

Ovo su zapanjujuće brojke.

With the building industry responsible for 40% of global carbon emissions – we have an undeniable responsibility to reduce our impact on climate change and pursue sustainable and climate-resilient construction to create, build and shape our cities into resilient cities. 

Agenda Ujedinjenih naroda za održivi razvoj do 2030. (SDGs).) ističe potrebu za otpornim gradovima u nizu svojih ciljeva, eksplicitno i implicitno:

• Do 2030. „izgraditi otpornost siromašnih i onih u ranjivim situacijama te smanjiti njihovu izloženost i ranjivost na ekstremne događaje povezane s klimom i druge ekonomske, društvene i ekološke šokove i katastrofe” (Cilj 1.5, Ujedinjeni narodi 2030 SDG)

• „Učiniti gradove i ljudska naselja uključivima, sigurnima, otpornima i održivima” (Cilj 11, Ujedinjeni narodi 2030 SDG)

• „Ojačati otpornost i sposobnost prilagodbe na opasnosti i prirodne katastrofe povezane s klimom” (Cilj 13, SDG Ujedinjenih naroda)

Izgradnja otporna na klimatske uvjete

Climate resilience takes into account both acute events (heat waves, heavy downpours, hurricanes, or wildfires) and chronic events (rising sea levels, worsening air quality, and population migration). Climate resilient construction involves designing, inženjering and building infrastructre that can withstand these acute and chronic events. It could mean passive ventilation to prevent overheating, expanded water storage, off-grid back-up power or mitigation of flood risks to name just a few.

It is generally considered that very few cities are currently equipped to deal with more frequent extreme weather events. There are some cities that have taken proactive measures to adapt their cities to protect against the effects of the climate crisis.

Barcelona, Greater Manchester, Helsingborg and Milan were unveiled in November 2021 by the Učinimo gradove otpornima 2030 kao prva četiri europska grada koja su prepoznata kao „centri otpornosti” zbog svoje politike i rada na zagovaranju u rješavanju rastućih rizika od klime i katastrofa.

Možda je to jedan od najznačajnijih klimatskih utjecaja na grad izgrađeno okruženje is the urban heat island (UHI) effect which essentially amplifies global warming, with temperatures rising significantly in cities. UHI is caused by the high thermal capacity (heat absorption) of concrete, asphalt and other dark coloured materials in the built environment.

Some cities are designing infrastructure to specifically combat UHI: Copenhagen, Denmark (which has pledged to become the first city to go fully carbon neutral by 2025, despite a rastuće stanovništvo) is cooling the city with seawater from the harbour; Four cities in Poland are using rainwater to combat the UHI effect with Green Bus Stops; Urban green spaces and green roofs can be seen in a number of cities such as Fukuoka, Japan and Paris, France.

Around the world, we can see many examples of how resilence can be embeeded at the core of design and construction:

• The Philippines has adopted dome-shaped roofs to withstand strong winds and typhoons. Strong winds can also be combatted with slopes with multiple roofs, central shafts to reduce wind force and pressure to the roof by sucking in air from outside, and using frangible architecture to prevent structural damage.

• In China, the Sponge Cities Project is piloting eco-engineering solutions to absorb and reuse rainwater in over 30 metropolises to reduce flooding risks.

• Miami is raising street levels and developing green infrastructure.

• Bangladeš ima plutajuću višenamjensku zgradu koja bi se oslanjala na stupove s plutajućim spremnicima koji je podižu tijekom poplava.

• Za prilagodbu hladnoj i umjerenoj klimi umjesto betona mogu se koristiti vodeni zidovi. Vodeni zidovi sadrže bačve s vodom za pohranu topline i osiguravaju toplinsku masu i bržu izmjenu topline od betona ili zida.

Na ove primjere, kao i na mnoge druge, možemo gledati kao na modele za to kako potencijalno možemo modificirati i ojačati naše izgrađene okoliše i zaštititi urbana središta od utjecaja zagrijavanja planeta.