Tuesday, 10 January 2017

Global Warming

This is an edit of an article I first posted several years ago. It was a parody response from an Extra-terrestrial, to someone who couldn't get their head round the paradox of global warming and the impending ice-age.....

Much conjecture surrounds the ability to predict climate change. Serbian astronomer and geophysicist Milutin Milankovitch theorised collective differences in the Earth's cycles were responsible for climate change. In some respects I agree this is a plausible method to indicate change. I have to dismiss 100% accuracy on the grounds there are too many variables to take into consideration, some impossible to calculate.

The Earth has a variety of cycles which Milankovitch calculated. Take first the Earth's orbit of the Sun. The Earth has an elliptical orbit but it isn't regular. The eccentricity of the orbit moves between 0.000055 which is almost circular, to 0.0679 (high eccentricity) with a logarithmic mean of 0.0019 the present is 0.0017 and decreasing. There are other factors to be taken into consideration and the overall cycle averages at around 100,000 years. The gravitational fields of Jupiter and Saturn have an influence, without them the eccentricity would be minimal.

In addition there is an apsidal precession. That is to say as the Earth orbits the Sun, the orbit itself rotates. The gif below is exaggerated for visual effect.

Then there is axial precession in 26,000 year cycles, and orbital inclination (70,000 years) which was overlooked by Milankovitch, as nothing was known then of this undulating motion of the Earth in its orbit. So as you can see the factors are many, but one of the most significant in my opinion is the axial tilt (obliquity). The obliquity variations range between 22.1 and 24.5 degrees moving from one to the other and back again over a period of 41,000 years. Currently we are at 23.4 degrees - about halfway between extremes - and reducing.

The last maximum was 10,000 years ago, the end of the last ice age. Go back a further 20,000 years to the minimum and we find ourselves back at the beginning of the ice age. This makes perfect sense due to insolation or solar irradiance. On an annual average the poles receive less insolation than does the equator, because the poles are always angled more away from the sun than the tropics. At a lower angle the light must travel through more atmosphere. By absorption and scattering there is a further reduction of polar insolation.

If we look at the history, the Earth is heading into another ice age which should peak in another 11,000 years or so. The affects will be felt long before then, sooner than many would imagine.

Now I've just skirted around this method of prediction for very good reasons. For one, to fully explain and discuss the flaws and merits of Milankovitch's work would take more than one post. The other reason is simply because it has no practical application. As already stated there are too many other factors at work.

Let's take the melt-down from last time for instance. Scientists state the ice age ended about 10,000 years ago which I will agree with on principal i.e. I see no reason to dispute it and feel extensive research in that area unnecessary. My bone of contention is how long it took. A figure of 5,000 years ties in nicely with other world events. The biblical flood and many others occurred between 3200-2800 BCE when analysing data and piecing together clues. These deluges are widely recorded in myths and folklore from around the world during this period. The Chinese deluge seems to be dated a little earlier - perhaps as much as 300 years - but naturally all 'evidence' is sketchy.

The discrepancy in dates makes me believe that although rising sea-levels caused mass flooding on a global scale, it probably wasn't all at the same time. The worrying thing is if it took 5,000 years to thaw after the end of the ice age, at what point did the prior 'freeze over' become significant before peaking. Then there is the human factor. It may appear a paradox that global warming will hasten the onset of the next ice age, but that is exactly what it is doing.

Vast amounts of fresh water from frozen polar ice is throwing the Gulf Stream out of sync. The Gulf Stream circulates warm currents from the tropics around the North Atlantic and it is these warm waters that insulate the UK and much of Northern Europe. If the Gulf Stream stalls or is unable to work its way north due to this heavier fresh water then a big freeze will come sooner rather than later.

This shows one problem with the Milankovitch theory but there are many others. A super-volcano or an asteroid strike would sufficiently pollute the atmosphere to potentially shut out the Sun. The main concern is that a couple of years ago it was estimated the Arctic will be ice-free by 2040 yet things have been deteriorating much faster than first thought.
  • Greenland holds 10% of the total global ice mass, were it to melt sea-levels would rise 21 feet. If other regions lost another 40% the rise would be over 100 feet (30 metres). Suddenly a deluge on a biblical scale doesn't seem so implausible.
  • After existing for many millennia, the northern section of the Larsen B ice shelf in Antarctica collapsed between January and March 2002, disintegrating at a rate that astonished scientists. Since 1995, the ice shelf's area has shrunk by 40 percent.
  • Arctic sea ice extent set an all-time record low in September 2007, with almost half a million square miles less ice than the previous record set in September 2005. Over the past 3 decades, more than a million square miles of perennial sea ice has disappeared, an area the size of Norway, Denmark and Sweden combined.
There seems to be little in the way of a contingency plan for this inevitable eventuality. Millions of people worldwide will be affected and due to the sheer scale, emergency services will be powerless to help the victims. We will see floods like we have been seeing already but one day the waters will remain instead of subsiding and more will follow. I suggest you move away from coastal areas or start building a boat!

No comments:

Post a Comment