Scientists have warned that global warming will soon hit us where it hurts the most: kidneys. In their new study published in Proceedings of the Natural Academy of Scientists journal Tuesday, two Texas University urologists Margaret Peale and Yair Lotan say that as world temperatures rise, more and more people will develop kidney stones.

They said a hotter climate will make people more and more dehydrated, leading to them to develop kidney stones. Explaining the looming health hazard, the two urologists said that urine keeps the body clean by carrying chemical waste out of it. But in warmer temperatures people will get dehydrated easily, reducing their urine production.

With not enough urine to wash mineral salts out of the body, these chemical wastes will develop into stones, they warned. To back up their study, they cited the example of the so-called kidney stone belt in the US - from Louisiana to Florida and then up north to Tennessee. This hot and humid part of the US, they said, reported more cases of kidney stones than elsewhere in the country.

With temperatures forecast to rise appreciably in the coming decades, the two urologists said the so-called kidney belt will expand up north, sweeping more US states and reaching Canada. As part of their study, they compared kidney stone cases reported from different regions of the US. Then they compared the number of these cases with temperature records of those regions, concluding that the rate of kidney stones was higher in comparatively hot and humid states.

Using computer models, they predicted that the warmer climate will push the kidney stone belt northwards, increasing kidney stone cases in those areas by as much as 30 per cent by 2050. Statistics show that one in every 10 men in North America develops kidney stones in their lifetime.