Keeping Shanghai Above Water in a Changing Climate

It's the most evocative image of this China on the move.
Built on a piece of land that three decades ago was only mud
this forest of skyscrapers reflects how far can the human ambition go.
But also, as a symbol of the times to come,
this urban landscape reveals how we trapped ourselves.
The menace for this postcard is called 'climate change'.
The polar edges of the Earth are sweating.
Upstream of the Yangtze river, the Himalayan glaciers are melting.
And as temperatures increase, the oceans expand their volume.
Slowly, the raising level of waters is noticeable, also here in Shanghai.
Zhang Zhenyu knows how serious the problem is.
His work at this room is to make sure that water doesn't go beyond the safety levels.
The screens register each change at major water ways, locks and reservoirs
with dozens of monitoring stations spread all around the city.
Zhang Zhenyu, Deputy Director Shanghai Flood Control Headquarters
"Shanghai is a low lying city surrounded by the Donghai sea
the Yangtze River and the Taihu Lake, in the North.
The altitude average is only 3 to 4 meters.
But the highest tidemark registered reached 5.72 meters
which means that Shanghai would be all flooded by more than 2 meters
if we didn't have the control measures.
That, in a city like Shanghai, would be a total catastrophe."
This is the site of the world's most important and busiest cargo port.
Shanghai is also China's economic engine
and a serious contender for the title of Asia's main financial center.
But in the same way as New York, London, Mumbai or Amsterdam
its success is menaced by the growing global warming.
Almost a quarter of the world's population live in coastal low-lying areas
the first to be wolfed down by rising tides.
Soon, they will be more and more, as cities become mega-cities
with the arrival of those looking to make progress.
In China, this urbanization process not only has been fast and at an enormous scale
but it has also followed a clear pattern:
from the rural and poor West to the Coast
urban, dynamic and at full steam.
Twenty million have already carved out a place for themselves in Shanghai
a name that, ironically, means 'Over the Sea'.
Ren Wenwei, Head of Shanghai Conservation Program World Wildlife Fund (WWF) China
"Shanghai, in the 1980's faced a serious problem of sediments, of sinking
since they used ground water.
But, later, the government realized this is a serious problem
so they stopped using this ground water.
So the sinking slowed down. But currently, it's still a little bit sinking."
Ren and his team have estimated that temperatures across the Yangtze River Basin
will increase between 1.5 and 2 degrees Celsius during the next 50 years.
The heat will make thunderstorms and floods more frequent
as well as droughts in a highly-populated area
that is considered the country's granary.
Typhoons already agitate the waters of the Huangpu river each year.
But according to the experts, climate change will push their trajectory northwards.
To target right at the heart of Shanghai.
"The water level is going to rise by 11 centimeters by 2030.
By 2050 and from now, it's going to rise 21 centimeters.
From our studies, we have registered that during the last 3 decades
Shanghai's sea level has already raised by 11.5 centimeters."
These are conservative numbers when taking into account other studies
that estimate increases of between one meter and 1,5 meters by the end of this century.
And in its way, the sea water taints the freshwater supplies as it turns it salty
slows the drainage of the flood basin and eats away the Delta's shores.
South of Shanghai, the erosion is a cause of concern.
"This Yangtze River Delta has played a very important role
in China's economic development.
So, if Shanghai realizes that climate change is a very big stress
they will take a lot of adaptive measures".
This 100-meter long barrier regulates the amount of water that slips into Shanghai.
Twice a day, the lock goes up or down
according to the sea-tides or the weather conditions.
At almost 6 meters height, it was designed
just over the highest increase of water levels registered in the last century.
When a powerful typhoon made the Huangpu overflow more than a decade ago.
Shanghai also has its own Great Wall, a 523-kilometer long
stretch of walls to protect itself from flooding. Will that be enough?
"In order to react tot he influence of the rising sea level
if we just increase the height of the protection walls or build new ones
this will cost a lot of money.
So now, we have a better and more economical way
which is to build a new waterlock in Wusongkou
right at the entrance of the sea
to avoid replacing the whole system.
We think this is a more economical and reasonable solution."
Once the barrier is down, the signal is received by the boats
and the gate remains open for the next couple of hours, until the next tide.
But opening and closing the net of waterways or surrounding ourselves with walls
is not enough for everybody.
"We want the government to take a more natural solution.
We call it "work with nature".
Since the dykes are not enough, we should use the wetland
and the natural habitat, to protect us.
Not using the dykes".
Apart from reducing the impact of humans on the wetlands
the environmental group claims that Shanghai
needs to reinforce its energy and transportation infrastructure.
Because the same way nature does
adaptation to climate change is part of the solution.
The bill will be big, though.
The Copenhaguen meeting will debate if the payment should come from the ones that polluted first
from those who are suffering the consequences or, if otherwise
we should all share the cost of living with the menace of rising tides.
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