The rain in Wales may be getting warmer

(Letter to the South Wales Evening Post)

For the benefit of Liz Eales (‘Mysteries of Wales’ water’, Have Your Say, Thursday 13 September) and others who seek to imply that the wettest summer since 1912 is evidence against the idea of man-made climate change; this is how it works.

The increase in (man-made) greenhouse gases in the Artic region has lead to a record thaw this summer.  Dr Edmund Hansen of the Norwegian Polar Institute describes this summer’s melt as “unprecedented in at least as much as 1500 years”.

This melt has released billions of tons of fresh water into the North Atlantic, thus significantly reducing the salinity of the northern ocean.

The reduction in salinity has lead to greater volumes of water vapour being taken up by the prevailing winds into the atmosphere.  These prevailing winds move this water vapour across the Atlantic and deposit it as rain on the first landmass they encounter – either the British Isles or Northern Europe.

More water in the atmosphere means more rain for us.  Simples.

The wet summer we have just encountered is strong evidence in support of man-made climate change; and the bad news is that further melting of the polar ice could lead to a southward shift in the Gulf Stream, which would mean more rain for the British Isles in future.

But perhaps we can draw some comfort from the fact that if all the windy-nimbys and climate change deniers have their way, at least it will be warm rain!

Yours,

Keith M Ross

Advertisement