Scientists have long projected that areas north and south of the tropics will grow drier in a warming world -- from the Middle East through the European Riviera to the American Southwest, from sub-Saharan Africa to parts of Australia.
These regions are too far from the equator to benefit from the moist columns of heated air that result in steamy afternoon downpours. And the additional precipitation foreseen as more water evaporates from the seas is mostly expected to fall at higher latitudes. Essentially, a lot of climate scientists say, these regions may start to feel more like deserts under the influence of global warming.
Now scientists have measured a rapid recent expansion of desert-like barrenness in the subtropical oceans -- in places where surface waters have also been steadily warming. There could be a link to human-driven climate change, but it's too soon to tell, the scientists said.