Unprecedented disasters or underwhelming action?

I flew to S?o Paulo in January from Auckland New Zealand in the middle of fatal and destructive flooding from the greatest daily and monthly rainfall ever recorded in Auckland (249mm in 24hrs).?The journey ended up lasting 56 hours, including camping out on carpet in the flooded airport. Within three weeks, the coast nearby in S?o Paulo was also breaking records with more tragic effects.

You’re looking at maps showing flooding of Camburi and Barra do Sahy on S?o Paulo’s North Coast (Litoral Norte), site of the recent disaster.?

However, this is not the flooding of February 2023 that rocked the coastal communities here, taking some 46 lives, but publicly available maps of likely flooding, whose mapping started nearly 20 years ago.? The images above are just two of many in the region from recent years.?

On 18 February, S?o Paulo’s north coast experienced a range of natural disasters, landslides collapsed houses, floods filled streets and dwellings and transported cars. At latest count 46 have lost their lives.

682mm of water fell in coastal town Bertioga, the greatest amount recorded in 24hrs in Brazil’s history.?For perspective, this single-day downpour exceeds the rain received annually in a “rainy” European capital like London.?The flooding was described as completely unprecedented.?But was it?

Through a lens of landscape and development, the coast is a curious place.

The dramatic Serra do Mar ranges form the backdrop for beach after beautiful beach of laid back surf-towns, where community dwellings cluster around houses and condominiums, award winning modernist architecture sits alongside more eclectic hippy era self-built homes that come down to lap the sea (pé na areia).?

The signs of accelerating development are there, with dense modern apartment constructions an increasingly common site and aerial maps showing brutal geometric patterns cutting away swathes of forest.?

60% of Brazil’s population lives in coastal cities, ?and local concentrations can be much greater (e.g. 82% of the population of the city Recife, in Brazil’s North, lives within 30 meters of the coastline).?Many of the locations where these cities are sited were flat floodplains and marshes, easily developed or reclaimed.

While not necessarily visible, the informal nature of land occupation becomes quickly obvious too. ?The Ministry of Urban Development estimates that half of Brazilian dwellings have no legal property tenure, transcending class, occurring in poor and rich communities alike.?S?o Paulo’s North Coast is no exception; schools, waste-systems and water supplies frequently would not happen without community initiatives.?40% of the inhabitants aren’t connected to a wastewater system, 26% have no central water supply.?Land title is rare and building work is more likely to start based on availability of money or labour than building standards and permits. ?

S?o Paulo’s coast is one of the most beautiful places in Brazil.?It’s a place with white beaches backed by palms, friendly and creative communities and a much slower pace than the neighbouring city of 12 million. ?Beach towns in the S?o Sebasti?o municipality, like Barra da Sahy, Baleia and Camburi (all affected by the recent weather) owe much of their beauty to their landscape, flat marsh and floodplain areas convenient for development, squeezed close to the sea by dramatic mountain chains, lush with forest and biodiversity. ?

Much of that lushness comes from a healthy does of rain that hammers the coast between those blazing hot beach days. As moisture comes in off the sea it thumps the?North coast’s sharp ranges and rapidly climbs, forming clouds and inevitably rain, the water flowing urgently down the ranges’ steep relief. The coast is no stranger to rain. Look closer at existing areas and you’ll see occasional flood damage or provisions, like private water-tight flood gates.

Regular visits and a technical curiosity led me some years ago to seek out disaster maps and water quality reports for the coast (municipalities the world over generate these, to varying levels of accuracy).?Data from water monitoring drew me to Camburi’s pristine waters, while flood mapping warned that large portions of its neighbourhoods would readily be under water, lashed by the red and orange tongues stretching across the chart.?The pattern repeats itself, the bulk of coastal towns sit bang in the next flood or landslide.

According to IPCC scenarios, your average Brazilian could see sea-levels rise up to a metre (worst case) by the time they reach old-age.?Beyond sea-level rise and atmospheric warming, dramatic weather is expected to accompany climate change, making it more complex than merely checking you have an extra metre to spare before the tide can creep over your beachfront boundary.?

Rivers seeking a path to the sea are met with higher tides and more dramatic sea surges coming the other way, pushing problems upstream.? 2005’s Hurricane Katrina infamous flooding was accompanied by only a fraction of the rainfall that S?o Sebasti?o received in February but winds and a massive storm surge slammed into Louisiana, combining with rainfall to cause direct devastation and stress levee systems to disastrous effect.?

The capacity of natural and manmade drainage systems is already strained on the coast. ?The constant march of development (more people, intense condominium living, paved roads and areas, increasing tourist visits) and the slow but inevitable crawl of climate change means the historic patterns on which local communities rely for their judgement of risk are no longer reliable. I was regularly told I would not find a place if I wanted to avoid a little flooding, reflecting a general complacency and stoicism - unfortunately, a few years experience navigating sodden streets is not a great predictor of how bad it could have been, or how bad it will become.? With climate changing, systems designed decades ago to fail only under a 50-year rainfall event are now likely to be overwhelmed in an event of decade or two. As we go forward, much less. ?

So was the tragedy on the North coast foreseen or preventable? ?

Engineer Xico Graziano, former secretary of Environment for Sao Paulo, state thinks so.?He said years have passed since risks in the relevant areas have been mapped and their potential consequences known. ?Climatologist and General coordinator of CEMADEN (National Alert Center) Jose Marengo describes these events as “a film that keeps repeating itself” pointing to local planning controls as the way forward.?

For me there is a deeper connection here with Brazil, and the world’s overall readiness for climate change.?That weekend’s tragedy speaks to threats and to development we can already touch and feel, and yet have not been responded to structurally.?Many regions of Brazil do not have adequate assessments and planning of climate change and those that do have acknowledged fundamental gaps in the data needed to forma. Response. ?

With climatic change bringing more volatile rainfall patterns, sea level rise and extreme events, the forecast is unfortunately ever clearer. ?

Brazilian response to climate change: 2022 - https://earthjournalism.net/stories/brazil-needs-to-strengthen-its-response-to-climate-impacts-in-coastal-zones