Global Water Supply Shrinks in Rainier World

Even in a world with more intense rain, communities could begin to run short of water.  New research has confirmed that, in a warming world, extremes of drought have begun to diminish the world’s groundwater – and ever more intense rainstorms will do little to make up the loss in the global water supply.

And a second, separate study delivers support for this seeming paradox:  worldwide, there is evidence that rainfall patterns are, increasingly, being disturbed.  The number of record-dry months has increased overall.  And so has the number of record-breaking rainy months.

Both studies match predictions in a world of climate change driven by ever-higher ratios of greenhouse gases in the atmosphere, from ever-increasing combustion of fossil fuels. But, unlike many climate studies, neither of these is based on computer simulation of predicted change.

Each is instead based on the meticulous analysis of huge quantities of on-the-ground data.  Together they provide substance to a 40-year-old prediction of climate change research:  that in a warming world, those regions already wet will get ever more rain, while the drylands will tend to become increasingly more arid.

As global temperatures creep up – and they have already risen by 1°C in the past century, and could be set to reach 3°C by 2100 – so does the capacity of the atmosphere to absorb more moisture.  It follows that more rain must fall.  But at the same time more groundwater evaporates, and the risk of damaging drought increases.

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