China's new 'Great Wall' not so great

China's second great wall, a vast seawall covering more than half of the country's mainland coastline, may be a foundation for economic growth but it can also result ecological disasters that can extend beyond China, says a study.

"These coastal areas are a perfect example of coupled human and natural systems," said one of study authors Jianguo "Jack" Liu from Michigan State University.

"The decisions being made in China are having enormous consequences to people and ecosystem services in China and the rest of the world. We must bring ecosystem services to the business table for a sustainable future," Liu added.

To create extra land for the rapidly growing economy, coastal wetlands have been enclosed by thousands of kilometers of seawalls, whose length exceeds that of China's famous ancient "Great Wall".

This new "Great Wall", covering 60 percent of the total length of coast-line along mainland China, caused a dramatic decline in internationally shared biodiversity and associated ecosystem services and will threaten regional ecological security and sustainable development, the researchers noted.

They found that the wetland ecosystems support a daunting number of birds, millions of which rely on the coastlines as they migrate.

The coastlines produce 28 million tonnes of fishery products, nearly 20 percent of the world's total.

Looking deeper reveals abundant biodiversity and a support system that also provides other invaluable but underappreciated services for people.

The authors note that while there are laws aimed at protecting coastal wetlands, they lack teeth, and are inadequate in face of the immediate profits.

The study appeared in the journal Science.