The balance sheet between blue and green

‘A thin blue line’. Of policemen edging a protest march? The blue halo of Earth’s fragile atmosphere as seen from space? No – in this case, a blue line that Robert Alcock painted along a sea-wall in Bilbao in 2011, one metre above high water mark.

He, like me, has spent part of his life guddling amongst the ecosystems of the sea shore: the rhythm of our lives – like those of the marine fauna and flora – ruled each day, week, month, by the changing levels of the sea. (Somebody once asked me whether my shore-walks – to the lower shore – were always at 9am. Since then, I have always taken a print-out of the daily highs and lows of the tide on the Solway shore.)

The tides at Silloth: daily highs and lows (from the EasyTide website)

The tides at Silloth: daily highs and lows (from the EasyTide website,

Robert, who describes himself as a “faint-hearted activist”, writes about the blue line, his “small act of civil disobedience” in a post on the Dark Mountain website, and I’ll return to the point of his protest shortly.

The form and shape of our coastline is a net result of the balance sheet, the plus and minus, of the relative levels of the sea and the land at any particular time. Those levels were consequences, not causes, the result of the changing interplay between the thick glaciers that weighed down the land-mass, and the effect of the ‘thin blue line’ of the atmosphere on the temperature of the land and sea. When glaciers melted, fresh water caused sea-levels to rise: but the land, freed of the crushing weight of ice, rose too – ‘glacioisostatic rebound’ – and the balance sheet kept shifting between loss and gain.

The effects of these changes in recent geological time are clearly visible on the South shore of the Solway Firth: the so-called ‘25-foot beach’, raised above the shore near Beckfoot, marks one of the periods when the rise in sea level overtook that of the rise of the land. The submerged forest on the mid-shore is a tangible indicator of a time of low sea-level, before the Firth even existed – a mere 8000 or so years ago – when the land was poorly-drained carse, with sparse forests and raised, peaty mires. Now, the peat and the spongey wooden trunks and roots of the forest appear and disappear, revealed or hidden according to the winds and ebb and flow of the tides.

Peast and tree: with grateful thanks to Joan Thirlaway for this photo

Peat and tree. My grateful thanks to Joan Thirlaway for this photo.

As I wrote in my own Dark Mountain guest post, the red sandstone cliffs of St Bees’ and the even older Carboniferous coal-bearing sandstones stretching out beneath the Firth from Whitehaven are evidence of more ancient geological periods, of rivers and richly-vegetated equatorial land raised above the sea. Although the mines have closed, coal still remains in rich seams, and the possibility has been recently raised that the mines may be worked again to provide “coking coal for industrial use”.

This brings us back to Robert Alcock’s thin blue line, the one-metre increase in sea-level in Bilbao. Last week the Fifth Assessment report of the International Panel on Climate Change was even clearer than previously about the impact of increased carbon dioxide levels on our climate; an assessment of work by 800 scientists, it clearly states the likelihood, based on statistical probabilities, relating to each topic they have considered. It reiterates that global sea levels are on the rise, due to melting of the polar ice-caps and to expansion of water as its temperature increases.

So what will the rise in sea-level mean for those of us living along the Solway or Bilbao shores? According to the IPCC,“Rates of sea-level rise over broad regions can be several times larger or smaller than the global mean sea-level rise for periods of several decades, due to fluctuations in ocean circulation. Since 1993, the regional rates for the Western Pacific are up to three times larger than the global mean, while those for much of the Eastern Pacific are near zero or negative.” An excellent discussion about the global distribution of sea-level changes, with accompanying maps, can be found on the RealClimate website (‘climate science from climate scientists’).

Storm surge at Allonby January 2014 (photo: Ann Lingard)

Storm surge at Allonby January 2014 (photo: Ann Lingard)

The land mass of South-West Scotland – and the Solway area – is still rising, at an estimated 1mm a year (1). But the highs and lows of the diurnal tides, now and at any time, are affected by the wind and barometric pressure, and last winter’s storm surge on the Solway made dramatic inroads along the coast; such extremes of weather are predicted to become more frequent.

I can tell you’re yawning. “Yes, yes, we’ve heard it all before … We’ve switched to energy-saving light-bulbs, we try not to use the car … But our efforts are a drop in the ocean, it’s governments who need to sort it out.”

So what shall we do to attract attention to the fact that time is running out? Paint a blue line along the wall of the Palace of Westminster’s terrace above the Thames, where MPs entertain their guests?
Protest outside the doors of the UK’s power-generating companies? Sorry, the owners aren’t here. You’ll have to cross the sea to find them – to Bilbao for Iberdrola, to France for EDF, and Germany for RWE and E.On (2) … Just as CO2 emissions are global, so too is the generation of power.

(1) Land of Mountain and Flood, the geology and landforms of Scotland. A McKirdy, J.Gordon & R. Crofts. Birlinn 2009. Page 208
(2). Private Island; why Britain now belongs to someone else. James Meek. Verso 2014

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