Posted
The ever-expanding, online archive of natural disaster footage has produced some surreal and disturbing images.
Video of last month's floods in Venice, however, seemed to reach a new level of dark absurdity. Waiters in gumboots waded through knee-high water, serving sodden diners pizza, while elsewhere people in wetsuits swam laps through Piazza San Marco — the city and the surrounding sea, indistinguishable.
Of course the presence of water, floods and high tides in Venice is a historical reality, a fact woven into the fabric of the city itself.
That today Venice is only one of many sinking cities, the speed at which those cities are sinking and the threat to urban populations, is altogether new.
The map of the world, climate scientists tell us, will be radically redrawn by the end of the century.
Video: Venice hit by high tide (ABC News)
The most recent IPCC Report revealed that the difference between 1.5 and 2 degrees warming, in terms of sea level rise, was about 10cm by 2100. The UN warns, the world is now on course for 3 degrees warming so global metropolises face an unprecedented threat.
"There are many cities around the world vulnerable to sea level rise ... Shanghai and Guangzhou, Jakarta, Bangkok, Dhaka, Alexandria, Lagos, New York, Miami, London and Cairns," says Professor Mark Howden, Director of the Climate Change Institute at ANU and Vice Chair of the IPCC.
"In many of these cases catchment development, groundwater extraction (which lowers land levels) and the sheer weight of the buildings is making the situation worse."
"The difference between, say 1.5C and 2C seems small within this century, but if temperatures are stabilised at those levels, over a few hundred years this difference could amount to several metres of sea level," he says.
Unsustainable urbanisation
Cities around the world are sinking for a range of reasons; what they have in common is a stark lack of preparedness and a pattern of unsustainable urbanisation, says Ashley Dawson, author of Extreme Cities: The Peril and Promise of Urban Life in the Age of Climate Change."Cities... are at the forefront of the coming climate chaos, their natural vulnerabilities heightened by social injustice," says Dawson, who is Professor of English at CUNY Graduate Center in New York City.
"Cities are both encountering extreme forms of weather as a result of climate change, from drought to inundation.
Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume.
"But in addition ... cities are extremely unequal. And you have to think about [the convergence of those] two different things to really understand what we are confronting."
Most global cities have large numbers of people living in so-called informal circumstances.
"[They're living] basically in slums, and those slums tend to be located in some of the most environmentally vulnerable parts of these cities," Professor Dawson says.
"That's going to have a major impact, particularly in tropical cities of Asia which are the ... centre for global urbanisation.
"A lot of cities in places like Australia and North America aren't necessarily centres of industrial production so their carbon footprint isn't because they are doing a lot of production, it's because of the way in which they're laid out with sprawling suburbs.
"That means you have a huge footprint as people drive around and emit a lot of carbon."
In the face of increasingly dire warnings and severe weather events much of today's urban development and infrastructure investment appears anomalous and decidedly counter intuitive.
"In the US there is a flood insurance program that pays people to rebuild in coastal areas after natural disasters like Hurricanes Harvey and Maria last year came through and destroyed parts of the US and Puerto Rico," Professor Dawson says.
He describes such processes as "completely dysfunctional", and nowhere is that dysfunction starker than in Miami, Florida.
"You get these luxury condos going up in places like Miami Beach where development should not be happening," he says.
"The problem of Miami is particularly grave and very different from other cities in the US ... the whole bottom part of Florida is built on limestone which is essentially like Swiss cheese.""So that means you can't build a wall or a dyke to hold back the ocean because it will just come up underneath.
"In fact what's happening in Miami and most of Southern Florida is that the ... drinking water for people in cities is getting pushed up higher and higher as the ocean intrudes underneath. And that means that drinking water sources for the city are increasingly threatened."
Water water everywhere but not a drop to drink
Climate change throws up many apparent paradoxes — the simultaneous occurrence of rising sea levels and drought is particularly challenging. Lack of water, as Australia knows all too well, can be as devastating as its excess.
Cities around the world are suffering through unprecedented drought. Germany's Rhine has been at record low levels, affecting vital shipping routes, while earlier this year drought pushed Cape Town dramatically close to 'day zero'.
Sao Paolo, Brazil has been particularly hard hit.
"Sao Paolo is a megacity ... and if you look at where it is on the map and look at other similar latitudes the ecosystems are much drier at that same point," Professor Dawson says.
"The reason that Sao Paolo has significant rainfall is the Amazon rainforest ... the trees in the rainforest are these kind of giant lungs that breathe in air that's pushed off the Atlantic ocean and then transpire a huge amount of water into the air — they are literally rivers in the air, which the Amazon rainforest creates.
"When there was a bad drought three or four years ago, scientists began looking at the connection between the drought and deforestation in the Amazon showing how there was a direct correlation."
The promise made recently by Brazil's far-right President-elect, Jair Bolsonaro, to champion the country's agribusiness sector and open up vast areas of the Amazon to development, does not bode well for the prospects of recovery.
"It's a really bleak scenario," says Dawson.
Rethinking urban design
In Sao Paolo, as in Miami and in urbanised coastal cities throughout the world, a radical new approach is required. Dr Rob Roggema, landscape architect and Director of Cittaideale, argues that we need to rethink the kinds of cities we are building."I think planning and design of our cities needs to be structurally and fundamentally done differently in order to increase the flexibility of the city to deal with [these] events.
"[This] requires flexible protection of the coast so that the impact of a storm or a storm surge or a sea level rise is not that [great] on the coastline. But we also need to look at the whole urban system that we tend to fix and there is not much space in the city at the moment to ... accommodate the impact of a storm."
Crucially, this kind of urban planning and transformation, he argues, has to happen in a decentralised way and requires planning now to avoid a potentially catastrophic future.
Professor Dawson says there is "a lot of amazing work" being done locally in cities, such as energy micro-grids in New York City that generate renewable power while providing income to marginalised communities.
"There's a lot of exciting ferment going on at the grassroots and on urban levels around the world," he says.
But he says a "fossil fuel-based, national populist wave is washing around the planet," making wider adoption of these kinds of forward-thinking solutions difficult.
"We really face a big challenge to scale this up."
No comments:
Post a Comment