Dhaka: Unrestrained climate change could have serious consequences by forcing Asian temperatures drastically upwards and it could limit economic growth and reverse recent human advances for hundreds of millions, according to a new study.

The Asian Development Bank and the Potsdam Institute for Climate Impact Research say in a new report that if humans continue to burn fossil fuels under the ‘business as usual’ scenario, then global average temperatures could rise by 4°C.

But over the landmass of Asia, summer temperatures could rise by 6°C and high mountain nations such as Afghanistan, Tajikistan, Pakistan and north-west China could register summer rises of 8°C above historic levels. Heat-related deaths among the elderly are predicted to rise by 52,000 cases by 2050.

These devastating temperatures would be accompanied by more rain – although Pakistan and Afghanistan could become much drier – and greater vulnerability to flooding as typhoons and tropical cyclones increase in intensity.

Global flood losses, set at $6bn a year in 2005, could rise to $52bn by 2050, and 13 Asian cities are among the 20 worldwide that can expect the greatest flood losses in the next 30 years.

Food production could be hit and rice yields in south-east Asia, for example, could drop by 50%.

The report, received from London, said food shortages could increase the count of malnourished children in South Asia by 7m.

Coral reefs in the region could be devastated by mass bleaching. Sea levels could rise by 1.4 metres by 2100 and go on rising over the centuries by more than five metres.

‘The global climate crisis is arguably the biggest challenge human civilisation faces in the 21^st century, with the Asia and Pacific region at the heart of it all, Bambang Susantono, of the Asian Development Bank, was quoted as saying in a report received from Climate News Network on Friday.

‘Home to two-thirds of the world’s poor, and regarded as one of the most vulnerable regions to climate change, countries in Asia and the Pacific are at the highest risk of plummeting into deeper poverty—and disaster—if mitigation and adaptation efforts are not quickly and strongly implemented.’

Over the last 25 years, per capita income in Asia and the Pacific has grown tenfold: so too have the cities. The world has 71 cities with more than 5m inhabitants, and 33 of these are in Asia.

These 33 are now home to 348m people. By 2030, they could be sheltering 483bn, a 40% growth in 15 years. By 2030, there could be another eight megacities, four in India.

But as wealth has increased, so has inequality. The poorest are most likely to be the greatest victims of unrestrained climate change.

‘The Asian countries hold Earth’s future in their hands. If they choose to protect themselves against dangerous climate change, they will help to save the entire planet,’ said Hans Joachim Schellnhuber, director of the Potsdam Institute.

‘Yet even adapting to 1.5°C temperature rise is a major task. So, on the other hand, Asian countries have to find strategies for ensuring prosperity and security under unavoidable climate change within a healthy global development,’ Professor Schellnhuber said.