Photographing Global Warming Ⅰ

2007-04-11 14:31:05 [ Big Normal Small ]  Mark Berthold  　Comment

A flock of birds in a moonlit sky.I cannot recall where I took this picture twenty years ago but it’s obviously still blessed with clear skies. Until recently we took the atmosphere for granted. But it has now been revealed as the most vulnerable part of earth’s ecological system. Carl Sagan has said “if you had a big globe with a coat of varnish on it, the thickness of that varnish relative to that globe is pretty much the same as the thickness of the Earth’s atmosphere compared to the earth itself.” Al Gore recounts this in his doco An Inconvenient Truth and its garnering the 2006 Best Documentary Oscar has helped concentrate our minds on this now pressing problem. In his stolid and stoic fashion Mr Gore explains:

[The atmosphere] is thin enough that we are capable of changing its composition –the sun’s radiation comes in the form of light waves heating up the earth and then some of the radiation that is absorbed and warms the earth is reradiated back into Space in the form of infrared radiation and some of the outgoing infrared radiation is trapped by this layer of atmosphere and held inside the atmosphere… the problem is this thin layer of atmosphere is being thickened by all of the global warming pollution that’s being put up there. And…this thickens this layer of atmosphere-more of the outgoing atmosphere is trapped and so the atmosphere heats up-this is global warming.”

Mr Gore identifies soaring carbon dioxide levels as the principal culprit of global warming. He charts the increase but Oxford Prof Robert M May is far more specific in what for my money is the much more engaging and cinematically stunning 2006 BBC series Planet Earth. He tells us that for thousands of years carbon dioxide levels coasted along at 280 parts per million of carbon dioxide. But they increased to 330 ppm in 1960, then to 360 by 1990s and now to 380 today. At this rate it will be 500 ppm by the middle of century. The last time such levels existed was 20-40 million years ago when oceans were 300 feet higher than now. To say the least a Venetian lifestyle will become more widespread!

On 6 April 2007, after four days of bitter debate, over a hundred countries agreed the text of a summary of the latest report of the Intergovernmental Panel on Climate Change-the most comprehensive to date. But, as they say, sometimes a picture is worth a thousand words.

I took this photo of Mt Kilimanjaro in 1989, before “global warming” had entered ordinary discourse. So different from the picture taken last year which Mr Gore features showing the peak now almost devoid of snow.

Mark Berthold copyright 2007

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