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Thursday, 21 July 2011

Climate change Lies, Damned Lies and Statistics

Lies, Damned Lies and Statistics

By Clive Wakely. 
Climate change, as the term suggests, is an ongoing process that has existed since our planet first evolved an atmosphere; it being dependent upon the presence of an atmosphere, irrespective of that atmosphere’s carbon dioxide content.
As we are all aware many thousands of years ago the earth was in the grip of an extended period of intense cold popularly known as the “Ice Age”.
During this period continental ice sheets and glaciers greatly extended, some remnants of which, the Greenland and Antarctic ice sheets for instance, being still with us.
Some 12,000 years ago this age of intense cold gradually morphed into a succession of relatively short-term periods of global warming and cooling, which have continued up to the present day.
Between 5000 and 3000 B.C., global temperatures are believed to have been generally higher than today. It was during this period that the first great human civilizations began to establish themselves and flourish.
Between 3000 and 2000 B.C., a period of global cooling occurred, resulting in a drop in sea levels as ice sheets and glaciers advanced again.
Later still, between 2000 and 1500 B.C. the earth experienced yet another period of global warming – which was followed by another cool period.
The Roman Empire (150 B.C. – 300 A.D.) occurred during this cooling period, which lasted throughout the “Dark Ages” until around 900 A.D.
The period 900 A.D. until 1200 A.D. was a time of global warming, referred today as the Medieval Warming Period, or Little Climatic Optimum.
There are indications that global temperatures then were at least as high as today and it was during this period that Viking settlements were established in previously inhospitable Greenland and Iceland.
As the Medieval Warming Period abated it was replaced by another period of global cooling. Between 1550 and 1850, temperatures were colder than at any other time since the end of the previous Ice Age, which is why it is often referred to as the “Little Ice Age”.
This is the time of “ice fairs” on the River Thames and frequent poor harvests resulting from long cold winters and mediocre summers.
However, since 1850, we have experienced a period of warming that coincided with the Industrial Revolution.
This period has also witnessed the greatest output of human induced carbon dioxide (CO2) ever, leading some in more recent years to speculate that the rise in atmospheric CO2 level is responsible for the increase in global temperature.
Proponents of this theory point to statistical evidence that suggests a correlation between the two factors, from which they conclude that one event is largely responsible for the other.
Even if this were true in this instance, it cannot explain previous pre-Industrial Revolution periods of global warming or cooling.
Indeed, it is one thing to plot statistical data on a graph, but quite another to correctly interpret it.
One of the primarily lessons of statistics is that correlation does not necessarily imply causation.
Simply put, two factors lining up on a graph do not necessarily imply a cause and effect relationship between them.
For instance, one could produce a graph plotting the growth in the size of the UK’s population against ever increasing petrol prices and conclude that the increase in this country’s population is because of the government’s fuel duty increases.
An alternative interpretation could be that ever-higher petrol prices are directly responsible for the explosion in UK population.
Simply because there appears to be a correlation between two factors, does not prove that there is; neither does it establish a cause and effect relationship between them.
Global Warming protagonists would have us believe, for a number of reasons, that there is a cause and effect relationship between a rise in atmospheric CO2 and an increase in global temperature.
That this is an interpretation, one that ignores the evidence which suggests other possibilities (derived from our planet’s historical climate change record), is an inconvenient truth too far for some; particularly those seeking to profit from carbon credit trading and investment in alternative green energy development.
US politician and alternative energy hedge-fund guru Al Gore popularized the CO2/temperature connection in his movie, An Inconvenient Truth, in which the alleged correlation between the two factors was demonstrated using the now notorious “Hockey Stick” graph.
His information was derived from research into CO2 atmospheric emissions in ancient ice core samples that initially appeared to support his case.
However in 2007, further paleoclimatic research concluded that deep-sea temperatures warmed about 1,300 years before the tropical surface ocean and well before the rise in atmospheric CO2 at the ending of the last ice age.
The importance of this finding is that it establishes that historically the rise in greenhouse gases, such as CO2, is more likely a result of warming than the cause of it.
In actual fact this was not new news. The same conclusion had been reach some four or five years previously in a less publicized study into microscopic air bubbles trapped in Antarctic ice core samples. These revealed a precise record of atmospheric greenhouse gas concentrations from which it was concluded that atmospheric CO2 increases lagged Antarctic deglacial warming by between 600 to 1000 years.
Put simply global warming is followed by CO2 atmospheric increase – not the reverse as the pro-global warming lobby would have us believe.
Al Gore’s “Hockey Stick” graph, for whatever reason, was interpreted as showing a direct correlation between atmospheric CO2 levels and global warming, with the former being responsible for the latter.
However, what pro-global warming proponents did not consider (or chose to ignore) was whether the increase in CO2 preceded or followed temperature increase.
For whatever reason their unshakeable conclusion was that because temperature and CO2 happen to line up on a graph, that CO2 must be the “smoking gun” and that vast investment in carbon credit trading and clean green alternative energy development was the only way to avoid Armageddon in the shape of runaway global warming.
Benjamin Disraeli is sometimes accredited with saying “there are lies, damned lies and statistics” – as far as global warming is concerned he was probably correct.