SCOTTISH Natural Heritage (SNH) proposes spending large sums to protect the Firth of Clyde coastline from the potential impact of global warming (“Coastline ‘must be realigned’ to protect it as sea levels in the Firth of Clyde rise”, The Herald, September 21).

The suggested impact on the coastal communities was a limited exercise based on a guess that the sea level in the Firth of Clyde would rise by 18 inches over the next 60 years.

However, a recent article published in the Geological Society of America (GSA) evaluated sea levels around the UK using, among other information, data from the Nasa Scientific Data Purchase Programme.

Its conclusion was that the sea level changes around Britain had marked variations.

The largest change calculated by the GSA was in the Firth of Clyde, with a significant lowering of the measured sea levels caused by the land rising.

This agrees with my observations over the past 70 years.

I live in Craighouse, Isle of Jura, just outside the Firth of Clyde, in a house on the beach.

Over this period the sea level has been slowly falling, not rising, especially over the past 40 years.

Donald McSwein,

Lag -na-bruaich, Craighouse,

Isle of Jura, Argyll.