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David Fogarty

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Typhoons Are Only Getting More Powerful as the Planet Warms

Posted: 01/17/2014 11:22 am

The intensity of tropical cyclones striking East Asia has sharply increased over the past 30 years and major cities and ports such as Shanghai in China could face a greater threat from more powerful storms in future, a study published on Thursday shows.

The study by South Korean scientists says more powerful storms have been sweeping further north and maintaining their intensity right before landfall along the coast of East Asia, particularly China, Japan and South Korea.

If the trend continues, which many scientists say is likely as sea surface temperatures rise, millions of people in low-lying coastal cities, vital trade ports, billion-dollar tourist beach-fronts and farmlands are at greater risk from flooding, wind damage and storm surges.

That possibility worries insurers, aid agencies and national disaster relief bodies, particularly after the death and devastation caused by Typhoon Haiyan in the Philippines late last year. Cyclones are known as typhoons in East Asia.

"If the past changes of large-scale environments are evidence or a result of global warming, it can be assumed that, in the future, more catastrophic tropical cyclones will strike East Asia than ever before," one of the authors of the study, Chang-Hoi Ho of Seoul National University, said in a statement.

To find out just where they might strike, he said the next stage of his team's research was to use climate models to predict future tropical cyclone landfall intensity in these regions.

The study's findings bolster the work of major reinsurers such as Swiss Re and Munich Re, which have been warning about the rising risks from flooding and storm surges to Asian megacities and coastal factory zones. As Asian economies continue to grow, more people and assets are in the path of storms and rising seas.

The authors of the study analysed five separate data sets that documented the evolution of tropical cyclones across the north-west Pacific between 1977 and 2010. They found the storms reached their maximum intensity more frequently just before landfall in East Asia.

"That is to say, tropical cyclones could intensify or sustain their strength up to the brink of landfall," they write in IOP Publishing's journal Environmental Research Letters. Haiyan, for example, was a maximum category five storm when it stuck and was one of the strongest cyclones ever recorded.

The coastlines of China, Korea and Japan in particular have experienced increasingly stronger cyclones, which the researchers have attributed to increasing sea surface temperatures and a change in atmospheric circulation patterns in the region.

Changes in sea surface temperature and wind flows meant that cyclones were more likely to track along coastal seas from the South China Sea upwards, meaning that by the time the cyclones hit the coastlines along northeast Asia they had gathered more energy and were at their maximum intensity.

The researchers also found that in waters near Taiwan and Vietnam, there was no substantial change in the intensity of tropical cyclones. While they found an increase in the number of storms, many formed in the South China Sea too close to land to reach maximum intensity.

In addition to increasing sea surface temperatures in the western Pacific, the scientists found that more powerful storms were being fed by a strengthening of the Walker circulation -- a major ocean-based atmospheric circulation system that drives weather in the tropical Pacific.

According to the researchers, the Walker circulation strengthens as the difference in sea surface temperature between the warmer western Pacific and the colder central-eastern Pacific increases. This leads to changes in wind flows that push storms towards the northeast coast of Asia.

The findings complement other studies and confirms the likely trend of more intense storms if mankind keeps pumping large amounts of greenhouse gases into the atmosphere. Warmer sea surface temperatures lead to more moisture evaporating into the atmosphere and more fuel for storms.

A major climate study in 2010, based on the results of a range of computer models, concluded there was likely to be a substantial increase in the number of storms globally in the severe category range of three to five. Overall, storms would be between 2 and 11 per cent more intense by 2100 and rainfall would increase about 20 per cent near the centre, it predicted.

The 2010 study also found that, with the exception of the Atlantic, there might be a drop in the number of storms in the Pacific and around Australia, but the storms that did form would tend to be more dangerous.

Swiss Re last year published a flood hotspot assessment for China. It found that of all the high-growth markets, China had the biggest flood loss potential. The country's most at-risk manufacturing centres were Shanghai and the Pearl River Delta near Hong Kong.

It said 52 per cent of China's industrial production centres were at risk of river flooding and 25 per cent from storm surges caused by cyclones. For the Pearl River Delta, the threat of storm surges and river flooding could cause insured losses of $35 billion and $9 billion respectively.

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  • Survivors bring bags of rice from a warehouse which they stormed due to shortage of food at typhoon-ravaged Tacloban city, Leyte province central Philippines on Monday, Nov. 11, 2013. (AP Photo/Aaron Favila)

  • Personnel of the Philippines Army 51st engineer corps load water for victims of Typhoon Haiyan at Villamor Air Force Base in Manila, Philippines, Monday, Nov. 11, 2013. (AP Photo/Wally Santana)

  • Residents queue up to receive treatment and relief supplies at Tacloban airport Monday Nov. 11, 2013, following Friday's super typhoon Haiyan that lashed this city and several provinces in central Philippines. (AP Photo/Bullit Marquez)

  • Residents queue up to receive treatment and relief supplies at Tacloban airport Monday Nov. 11, 2013, following Friday's typhoon Haiyan that lashed this city and several provinces in central Philippines. (AP Photo/Bullit Marquez)

  • Residents queue up to receive treatment and relief supplies at Tacloban airport Monday Nov. 11, 2013, following Friday's typhoon Haiyan that lashed this city and several provinces in central Philippines. (AP Photo/Bullit Marquez)

  • Residents queue up to receive treatment and relief supplies at Tacloban airport Monday Nov. 11, 2013, following Friday's typhoon Haiyan that lashed this city and several provinces in central Philippines. (AP Photo/Bullit Marquez)

  • Residents queue up to receive treatment and relief supplies at Tacloban airport Monday Nov. 11, 2013, following Friday's typhoon Haiyan that lashed this city and several provinces in central Philippines. (AP Photo/Bullit Marquez)

  • This aerial photo taken from a Philippine Air Force helicopter shows the devastation caused by Typhoon Haiyan in Guiuan, Eastern Samar province, central Philippines, Monday, Nov. 11, 2013. (AP Photo/Bullit Marquez)

  • An aerial image taken from a Philippine Air Force helicopter shows the devastation of the first landfall by typhoon Haiyan, Monday Nov. 11, 2013 in Guiuan, Eastern Samar province, central Philippines. (AP Photo/Bullit Marquez)

  • Soldiers prepare to load food supplies to a Philippine Air Force helicopter at Tacloban airport Monday Nov. 11, 2013, following Friday's typhoon Haiyan that lashed this city and several provinces in central Philippines. (AP Photo/Bullit Marquez)

  • A young survivor carries a bag of rice from a warehouse which they stormed due to shortage of food at Typhoon Haiyan-ravaged Tacloban city, Leyte province, central Philippines on Monday, Nov. 11, 2013. (AP Photo/Aaron Favila)

  • A man walks home with his son Monday Nov. 11, 2013 following Friday's devastating typhoon that lashed Hernani township, Eastern Samar province, central Philippines. (AP Photo/Bullit Marquez)

  • This aerial photo taken from a Philippine Air Force helicopter shows the devastation caused by Typhoon Haiyan in Tacloban city, Leyte province, central Philippines, Monday, Nov. 11, 2013. (AP Photo/Bullit Marquez)

  • Residents walk past the debris as others rebuild their houses Monday Nov. 11, 2013 following Friday's devastating typhoon that lashed Hernani township, Eastern Samar province, central Philippines. (AP Photo/Bullit Marquez)

  • Survivors move past the damages caused by Typhoon Haiyan in Tacloban city, Leyte province central Philippines on Monday, Nov. 11, 2013. (AP Photo/Aaron Favila)

  • A survivor walks beside a ship that was washed ashore hitting makeshift houses near an oil depot in Tacloban city, Leyte province central Philippines on Monday, Nov. 11, 2013. (AP Photo/Aaron Favila)

  • Residents rebuild their homes Monday Nov. 11, 2013 following Friday's typhoon Haiyan, that lashed Hernani township, Eastern Samar province, central Philippines. (AP Photo/Bullit Marquez)

  • Government troopers secure a downtown street to maintain order as reports of rampant looting spreads in Tacloban city, Leyte province, central Philippines on Monday, Nov. 11, 2013. (AP Photo/Aaron Favila)

  • A man, holding a boy, walks past dead bodies along the streets in typhoon-ravaged Tacloban city, Leyte province central Philippines on Monday, Nov. 11, 2013. (AP Photo/Aaron Favila)

  • A mother cries in relief upon boarding a Philippine Air Force helicopter, Monday Nov. 11, 2013 following Friday's typhoon Haiyan which lashed Guiuan township, Eastern Samar province, central Philippines. (AP Photo/Bullit Marquez)

  • Residents watch as others throw goods from a warehouse in Guiuan, Eastern Samar province, central Philippines Monday, Nov. 11, 2013, after typhoon Haiyan devastated the town Friday. (AP Photo/Ted Aljibe, Pool)

  • Residents rebuild their homes Monday Nov.11, 2013 following Friday's typhoon Haiyan that lashed Hernani township, Eastern Samar province, central Philippines. (AP Photo/Bullit Marquez)

  • Survivors carry bags of rice from a warehouse which they stormed due to shortage of food at typhoon-ravaged Tacloban city, Leyte province central Philippines on Monday, Nov. 11, 2013. (AP Photo/Aaron Favila)

  • Survivors move past the damages caused by Typhoon Haiyan in Tacloban city, Leyte province central Philippines on Monday, Nov. 11, 2013. (AP Photo/Aaron Favila)

  • Residents queue up to receive treatment and relief supplies at Tacloban airport Monday Nov.11, 2013, following Friday's typhoon Haiyan that lashed this city and several provinces in central Philippines. (AP Photo/Bullit Marquez)

  • This image provided by NASA shows Typhoon Haiyan taken by Astronaut Karen L. Nyberg aboard the International Space Station Saturday Nov. 9, 2013.

  • Residents look at bodies brought inside a damaged chapel Saturday, Nov. 9, 2013, a day after powerful Typhoon Haiyan slammed Tacloban city, in Leyte province in central Philippines.

  • A boy walks past the devastation brought about by powerful typhoon Haiyan at Tacloban city, in Leyte province in central Philippines Saturday Nov. 9, 2013.

  • A man sits in the debris with an uprooted tree seen in background, after powerful typhoon Haiyan slammed into Tacloban, central Philippines on Saturday, Nov. 9, 2013.

  • Survivors walk along a dark city as electricity has been cut after powerful Typhoon Haiyan slammed into Tacloban city, Leyte province, central Philippines on Saturday, Nov. 9, 2013.

  • A Philippine flag stands amongst the damage caused after powerful Typhoon Haiyan slammed into Tacloban city, Leyte province, central Philippines on Saturday, Nov. 9, 2013.

  • A woman stands amidst the devastation brought about by powerful Typhoon Haiyan at Tacloban city, in Leyte province, central Philippines Saturday Nov. 9, 2013.

  • A survivor carries relief goods amongst the devastation after powerful Typhoon Haiyan slammed into Tacloban city, Leyte province central Philippines on Saturday, Nov. 9, 2013.

  • A resident sifts through the rubble of his damaged house following a powerful typhoon that hit Tacloban city, in Leyte province, central Philippines Saturday Nov.9, 2013.

  • Tacloban city, devastated by powerful Typhoon Haiyan, is seen in Leyte province, central Philippines Saturday, Nov. 9, 2013.

  • Soldiers load relief supplies for airlift to affected areas Saturday Nov. 9, 2013, a day after powerful typhoon hit Tacloban city, in Leyte province in central Philippines.

  • In this image provided by NOAA Friday Nov. 8, 2013 which was taken at 12:30 a.m. EST shows Typhoon Haiyan as it crosses the Philippines.

  • A resident walks past high waves pounding the sea wall amidst strong winds as Typhoon Haiyan hit the city of Legaspi, Albay province, south of Manila on November 8, 2013.

  • A house is engulfed by the storm surge brought about by powerful typhoon Haiyan that hit Legazpi city, Albay province Friday Nov.8, 2013.

  • Residents clear a road after trees were toppled by strong winds at the onslaught of powerful typhoon Haiyan that hit the island province of Cebu, Philippines, Friday Nov. 8, 2013.

  • Soldiers make the rounds to enforce the evacuation of residents as powerful typhoon Haiyan hits Legazpi city, Albay province about 325 miles south of Manila, Philippines Friday.

  • Fisherman repair their outrigger on the shore of Manila bay as Typhoon Haiyan approached on November 7, 2013. (JAY DIRECTO/AFP/Getty Images)

  • Fisherman repair their outrigger on the shore of Manila bay as Typhoon Haiyan approached on November 7, 2013. (JAY DIRECTO/AFP/Getty Images)

  • Fisherman repair their outrigger on the shore of Manila bay as Typhoon Haiyan approached on November 7, 2013. (JAY DIRECTO/AFP/Getty Images)

  • Fisherman's outrigger are anchored on the shore of Manila bay as Typhoon Haiyan approached on November 7, 2013. (JAY DIRECTO/AFP/Getty Images)

  • Fisherman's outrigger are anchored on the shore of Manila bay as Typhoon Haiyan approached on November 7, 2013. (JAY DIRECTO/AFP/Getty Images)

  • This image provided by the U.S. Naval Research Lab shows Typhoon Haiyan taken by the NEXSAT satellite Thursday Nov. 7, 2013 at 2:30 a.m. EDT. (AP Photo/US Naval Research Lab)

 

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