Historical planning impacts on climate

When a floodplain is approved for housing, who decides it is a good idea to put people in areas where water naturally wants to go? If the flood risk model says “1-in-100 years,” the houses get built. But here’s the problem - those models are often based on historic data in a non-historic climate. They assume yesterday’s weather patterns will predict tomorrow’s reality. A drainage plan is submitted. A flood wall is proposed. The project moves forward. And just like that, what was once a wetland becomes a postcode that floods every other year. Developments get the green light because the “risk zone” maps haven’t been updated in over a decade - ignoring sea-level rise, extreme rainfall events, and the compound effects of urbanisation. Water doesn’t read planning approvals. It doesn’t respect council boundaries. And climate change doesn’t wait for a local plan update. What this reveals is a time-lag problem disguised as a safety check. We’re using outdated, narrow-scope data to make permanent decisions about dynamic, interconnected systems. If we want climate-resilient communities, we need to fix how risk is measured in the first place: Real-time climate data in planning decisions. Scenario modelling that accounts for 2050, not just 1950. A shift from “how do we protect this development?” to “should this development exist here at all?” If we think some of the costliest climate risks aren’t caused by nature, they’re authorised by paperwork that assumed nature would stay the same. Picture - Avi Steinberg for The New Yorker Cartoons

What's the link between #colonialism & #climate #vulnerability in the #Caribbean? In this new article that uses Georgetown, Guyana as a case, my Colby College students & I make 6️⃣ arguments: 1️⃣ Colonial-era economic activity & territorial control led to the establishment of Georgetown at its current site – a port built on a coastal flood plain that lies up to 3.5 m below sea level that is extremely vulnerable to flooding. 2️⃣ Georgetown's geographic characteristics & its vulnerability to climate risks & impacts are fundamentally a product of the complex colonial history of the Guyanese coast. 3️⃣ Georgetown's urban form is bound up with social hierarchies originating from its construction under the Dutch & perpetuated by the ‘divide-and-rule’ policies of the British. 4️⃣ Specific colonial-era institutions (laws & policies) relating to housing & town planning (e.g. Colonial Development & Welfare Act, the Town & Country Planning Act, the Housing Act) have had significant but not sole impacts on the extent of modern-day adaptive capacity in Georgetown. 5️⃣ Poor economic conditions & prospects have impacted many of the living conditions in the city & inhibited the local municipality's ability to moderate related issues such as water, sanitation & waste management. 6️⃣ Georgetown's adaptive capacity is the result of long-term processes & deep transformations relating to knowledge- & meaning-making & financing & strengthening local institutions are required. FREE access to the full article here ➡ https://lnkd.in/edrGD_x8

Climate change is the flavour across policy, research, civic action amongst other domains and rightly so. For nearly a decade now, a small team of planners at INDÉ (Integrated Design) is researching and evolving bottom-up climate responsive planning frameworks. While our work started with evolving bottom-up planning frameworks as a complement to the dominant top-down planning approach, very soon we realised that rapidly urbanising cities are caught unawares – even as historic challenges of basic service provision are mounting, newer challenges of changing climates have exacerbated existing inequities and inequalities. In engaging with multiple cities across India we gained an incremental understanding of climate impacts – especially on the urban poor. Climate hazards lead to varying degrees of vulnerability dependent on varied factors – physical, socioeconomic, environmental, geographical and political. Yet, a careful unpacking of conversations (conducted as part of various action research projects ) pointed to, in many cases, vulnerabilities mounting on account of shoddy urbanisation For instance, in Dharwad, flooding occurred in a slum abutting the main road when ‘slum-redevelopment’ led to a level difference between the newly tarred road that is at a higher level than the houses that abut this road.  https://lnkd.in/ggUXqpB5 Similary in a settlement in Bangalore, heat is exacerbated with increasing concretisation driven by the increasing demand for housing the migrants. In yet another settlement, inundation is frequent as the path of water is now blocked with a built foot print. In yet another instance, 'heat is unbearable when the highway replaced the trees.'  https://lnkd.in/gQyycdES In Ranchi agriculture pockets in numerous tribal hamlets in the city are quickly transitioning to rental housing as it 'provides higher income and is less backbreaking.' https://lnkd.in/g6ApnZZG There are numerous such vocabularies that we gathered through lived experiences around changing climates. As we unpack and analyse these vocabularies there is mounting evidence on urbanisation induced fragmentation of landscapes, embedded livelihoods, open spaces and everyday living that is exacerbating vulnerability. Addressing this vulnerability, we argue, requires a whole systems view that incorporates a course correction of urbanisation patterns and trajectories. This is getting further evidenced in our most recent work around Decoding Climate Science that builds on our earlier experiment around the decoding of heat concepts https://lnkd.in/gFABbc2e Cities across the country have an opportunity to address historic and contemporary challenges through Local Area Plans, Ward Plans -a scale ideal to addressing the intrinsically linked challenges of urbanisation and changing climates.

"Climate Change Demands a Reassessment of Flood Return Periods" Recent years have shown a dramatic increase in record-breaking rainfall and frequent extreme weather events, strongly suggesting that our traditional flood return periods 10, 25, or even 100 years may no longer reflect current reality. Around the world, we're constantly hearing news of "once in a century" rainfall and historic floods. This is a clear signal that the concept of the "100 year flood," which is based on historical data, can no longer keep pace with the reality of our changing climate. This raises a critical question for the design of civil infrastructure that underpins our society's safety. Our design standards have long been based on the principle of "climatic stationarity" the assumption that the future will look much like the past. Climate change has shattered this assumption, and relying on historical data alone to predict future risk is no longer viable. 🔹 Increased Risk for Permanent Bridges: Permanent bridges are typically designed to withstand 100 year or even 200-year flood events (Q100-Q200). But what if today's climate has turned the old 100-year event into a 30 or 50 year event? Our bridges will face their design limits far more frequently than anticipated, posing a serious threat to their safety and durability. 🔹 Greater Vulnerability for Temporary Structures: The problem is even more acute for temporary works, such as construction bypass bridges. For efficiency, these are often designed for much shorter return periods, like 2 year or 5 year floods (Q2-Q5). As rainfall intensity increases globally, the risk of catastrophic failure for these structures during their short service life has grown exponentially. A single "unexpected" storm can lead to immense loss of life and property. We need a paradigm shift. We can no longer rely solely on the records of the past. We must actively integrate forward-looking climate change scenarios and predictive models into our design standards. This means updating our design flood levels to reflect the potential for future extreme rainfall. This is about more than just increasing safety factors; it's about building resilient infrastructure that can adapt to a dynamic climate. #bridge #trestle #collapse #civil #engineering #construction #climate #flood

𝗜𝗻𝘁𝗲𝗴𝗿𝗮𝘁𝗶𝗻𝗴 𝗖𝗹𝗶𝗺𝗮𝘁𝗲 𝗖𝗵𝗮𝗻𝗴𝗲 𝗥𝗶𝘀𝗸𝘀 𝗶𝗻𝘁𝗼 𝗜𝗻𝗳𝗿𝗮𝘀𝘁𝗿𝘂𝗰𝘁𝘂𝗿𝗲 𝗗𝗲𝘀𝗶𝗴𝗻 𝗮𝗻𝗱 𝗠𝗮𝗶𝗻𝘁𝗲𝗻𝗮𝗻𝗰𝗲 Climate change increases not only the likelihood of hazards such as floods and storms but also their intensity and spatial reach. Since most infrastructure projects are designed for lifespans of up to a hundred years, it is essential to integrate climate risks into both design and maintenance planning. Traditionally, engineers have relied on historical data to estimate future risks. For example, the likely 100-year flood was calculated from past records, assuming that natural patterns remain constant. The core assumption behind this approach was that the future would behave like the past. This assumption held true until the late 20th century, when climate change began to invalidate it. The climate is now shifting too rapidly for the past to serve as a reliable guide. Therefore, climate change must be considered when estimating design parameters such as flood magnitude or peak discharge. For instance, the design flow for a dam spillway or the capacity of stormwater drains should account for future climate projections. Ignoring these changes can result in under-designed structures that fail under new conditions. As flood intensity increases, so does its spatial extent. Higher floods affect broader areas, expanding floodplains and putting new zones at risk. This expansion raises the cost of infrastructure development since higher safety factors or stronger materials are now required. Governments and institutions must allocate larger budgets for both constructing new infrastructure and maintaining existing ones. Existing infrastructure faces similar challenges. Structures built decades ago are now exposed to higher stresses than they were designed for, which increases the risk of deterioration and failure. This not only raises maintenance costs but also threatens human lives and economic stability. The dam break in Libya in 2023 is a tragic example. Beyond flooding, climate change alters river flows, reduces water availability, and increases the duration of dry seasons, affecting irrigation systems and hydropower generation. Urban drainage networks can be overwhelmed by intense storms, while rising temperatures reduce road lifespan and raise energy demand for cooling facilities. To conclude, it is now clear that the future will not resemble the past. Relying solely on historical data for infrastructure design is no longer practical. Engineers and policymakers must integrate climate projections into every stage of the infrastructure lifecycle. Doing so not only prevents failures but also protects public finances and ensures the sustainability of investments. Building climate-resilient infrastructure is therefore not only a technical requirement but also an economic necessity. The cost of inaction will always exceed the cost of preparedness.