first published in weblog seventy seven on Saturday 18th March 2006
Global warming is the theory that increased levels of carbon dioxide and certain other gases are causing an increase in the average temperature of the earth’s atmosphere because of the greenhouse effect.[1]
Imagine the composition of the earth’s atmosphere as a 100 yard football field. Most of the atmosphere is nitrogen so starting from the goal line this will get you to the seventy-eight yard line. Nearly all of what is left is oxygen which takes you to the ninety-nine yard line. Most of what remains after that is the inert gas argon which brings you to within three and a half inches of the goal line. That’s pretty much the thickness of the chalk stripe. How much of the remaining three inches is carbon dioxide? One inch. That’s how much CO2 we have in our atmosphere. One inch in a hundred yard football field. And do you know how much it has increased on our football field in the last 50 years? Three eighths of an inch…less than the thickness of a pencil.
Carbon dioxide is used by plants to photosynthesise. The plants take in the gas via small openings on the surface of their leaves called stomata that can open and close in response to atmospheric conditions and the plant needs. When the stomata are open some water is lost in a process called plant transpiration…plants sweat. Laboratory experiments have shown plants become more efficient in the presence of greater levels of carbon dioxide so the stomata do not open as often or for as long. More carbon dioxide means less transpiration which means more water stays in the soil.
It seems to be a well-known fact that the flow of many rivers around the world is increasing even though rainfall has changed very little in the last few decades. Aha…you have got there before me. Scientists and propagandists for global warming have their pseudo-scientific link between carbon dioxide in the atmosphere and rising sea levels. More water in the soil means more runs off into rivers which explains the increase in river flow and must lead in the fullness of time…and with the right parameters in the computer models…to the inundation of low-lying cities like New Orleans within all our lifetimes.
But sea levels are not rising…the last time I looked at the data a year or so ago there was no discernible shift over the past few decades. Of course sea levels move around. There was a disaster in Queensland over the weekend with sea levels changing by up to twelve feet for instance. And have you heard of tides? My sea level goes up and down like a yo-yo twice a day and the waters of the North Atlantic Ocean swirl around like water in a cooking basin. And do you remember in the days before the invention of global warming all the concern about the increasing run-off all over the world as hills were stripped of their trees and intensive agriculture decimated the natural vegetation cover. Increased run-off? Of course. But caused by plants getting fitter and sweating less in their extra fraction of an inch of carbon dioxide. Pull the other one. What complete and utter baloney.
Endnotes
[1] The level of carbon dioxide at the Zeppelin research station in Svalbard, about midway between mainland Norway and the north pole, was measured at 393.7 ppm on 28th April 2009, according to a report by the Guardian's science reporter John Vidal. He also noted that, before the industrial revolution, the level was about 280ppm; in 2008 it had been 394.5ppm; and a week earlier the level had 'peaked at more than 397 parts per million'.
