The rain band near the equator that determines the supply of freshwater
to nearly a billion people throughout the tropics and subtropics has
been creeping north for more than 300 years, probably because of a
warmer world, according to research published in the July issue of Nature Geoscience.
If the band continues to migrate at just less than a mile (1.4
kilometers) a year, which is the average for all the years it has been
moving north, then some Pacific islands near the equator – even those
that currently enjoy abundant rainfall – may be drier within decades
and starved of freshwater by midcentury or sooner. The prospect of
additional warming because of greenhouse gases means that situation
could happen even sooner.