CORRECTED-World's major cities to face 'unknown' climate conditions by 2050

A fifth of the world's major cities will face "unknown" climate conditions by 2050, researchers warned on Wednesday, as rising temperatures heighten the risks of drought and flooding.Climate scientists at the Crowther Lab, a research group based at ETH Zurich, a science and technology university, analysed 520 cities across the world, including all capitals and most urban centres with a population of more than 1 million.Looking at current climate conditions in these cities - including precipitati