A sharp rise in shipping emissions in east Asia is killing tens of thousands of people in the region every year and adding to global warming, a study said Monday.
The manufacturing and export hub has the world's fastest-growing rate of particle and carbon dioxide (CO2) pollution from shipping emissions, it said.
This is likely to grow as China pursues a policy of reviving the ancient Silk Road trade with Europe -- yet very little is known about the damage done by east Asia's shipping emissions.
A team of Chinese and American scientists used records of more than 18,000 vessels observed in the region in 2013 to calculate emissions and their likely effect.
They found that ship traffic in east Asia more than doubled since 2005.
Resulting emissions accounted for 16 percent of global shipping CO2 in 2013 -- up from about 4-7 percent from 2002 to 2005.
The region, which holds eight of the world's top ten container ports, now accounts for more than a sixth of global shipping activity and emissions, which are not controlled, the team reported in the journal Nature Climate Change.
"Increased emissions lead to large adverse health impacts with 14,500-37,500 premature deaths per year," they wrote.
The estimation was based on the known, relative contribution of air pollution to total deaths in a given population.
The team calculated that particle pollution from shipping fumes was responsible for about 18,000 deaths in mainland China, 3,600 in Japan, 1,100 in Taiwan, Hongkong and Macau, 800 in South Korea and 600 in Vietnam.
This was "an important though small fraction of the more than one million total premature deaths attributable to ambient air pollution in the same region," said the study.
Previous research had shown that about 70 percent of emissions from international shipping occur within 400 kilometres (216 nautical miles) of the coast.
"As a large fraction of vessels are registered elsewhere, joint efforts are necessary to reduce emissions and mitigate the climate and health impacts of shipping in the region," the researchers pointed out.
According to the International Maritime Organization, shipping contributed about 2.8 percent of global manmade greenhouse gas emissions between 2007 and 2012.