SUMMER holidays could soon become too hot to handle with experts predicting temperatures will continue to rise, driving vacationers to explore new destinations. And pensioners who have retired in search of warmer weather in places such as Florida and Queensland might become environmental refugees driven back to colder climates. Already this summer, tourists have been returning from Mediterranean resorts where temperatures hit 47 degrees Celsius in Spain and 43 in Turkey. With reports of heart attacks at the Acropolis in Athens and more than 70 people dying in Turkey after falling off rooftops as they tried to find cool places to sleep, some holidaymakers were cutting their losses and returning home. 'I know I won't be going there again,' said a Vicky, a young marketing executive returning to Britain from Turkey. 'We thought we were going to come up in heat blisters.' Experts who have studied records in Europe and China and examined tree rings and ice cores going back 1,000 years have been unable to find a hotter century and believe it will get even warmer. 'A whole body of different events is taking place which will mean it's not just going to get warmer, it's going to get a lot warmer,' senior research scientist at the University of East Anglia's climate research unit, David Viner, said. Experts believe temperatures will rise between 1.5 and 4.5 degrees over the next century unless steps are taken to reduce carbon monoxide emissions. The increase might not appear dramatic but the difference between the last Ice Age and now is only four degrees. Dr Viner said the changes might lead some to move out of warmer climates and others to reschedule holidays. But chairman of the World Travel and Tourism Council Geoffrey Lipman said holidaymakers would always go in search of sun and sand. 'Quite serious attempts are being made to try to open up the polar regions but the average person is still going to go after the sun,' he said. RECORD HIGH THE first seven months of this year equalled the hottest recorded by the Hong Kong Observatory since monitoring began in 1885. The mean temperature of 23.2 degrees Celsius, equalling the record set in 1973, was attributed to the El Nino effect.