Climate Chart manipulation and Key Data

I set out yesterday to pull together whatever evidence could be marshaled for annual temperature ranges since the Bronze age. after a short review of the literature, I was disconcerted to recognize that our available information has been aggressively manipulated to play down the Medieval warm spell and more recently to enhance the apparent effect of the recent rise. This last rise has been challenged and debunked. Do not get me wrong. Temperatures have risen as is their natural inclination in the northern hemisphere, but not even to the level of previous optimums as yet. The hockey stick chart was pretending otherwise.

The point that I am making is that I cannot trust the data presented, because scholars have apparently taken political positions and are pushing the limits of the data as offensive as that is.

So how do we get past that difficulty. As I have posted earlier, It is clear to me that the natural tendency of the northern hemisphere is to annually gain a little heat, while the opposite is true for the southern hemisphere. Certainly land distribution alone sets up this unique capacity. This means that the northern hemisphere will sustain a long slow warming trend that goes on for hundreds of years while the south simply gets a little colder. The north will eventually achieve an optimum that will appear quite stable.

More importantly, since the north is generally warming, any measured chart will tend to be volatile upward and very difficult pin down. That means that for any small section, the upward volatility will be the same. The same will not be true for periods in which there has been an injection of cold. The floor will drop dramatically and hold for a long time until warming effects take charge. I am of course positing that an injection of cold water takes place into the Atlantic basin over a fairly short period of time, turning over the heat imbalance that has built up.

What this means is that we need to carefully study the historical record for the onset of North European cold spells. That will typically reset the warming clock.

We had a cold spell kick off in the late fifteenth century, and also the late fifth century and somewhere back in the post 1000 BCE world. The two earliest had the effect of depopulating northern Europe and gave us the Sea peoples(also likely known as the Greeks) and in the fifth century wiped out the Western Roman Empire. This last time around, we merely suffered and overcame. Of course, we enthusiastically invaded the Americas and I suspect that the Indians never noticed the difference..

The point that I am making is that these cold spells are abrupt and very effective. The recovery seems to take around a thousand years. It also appears that the last half is quite balmy, as demonstrated by the conditions attested in the historical record.

Perhaps it is not an accident that the Romans were able to grab Western Europe for 500 years with the state of their agricultural technology.

There is every reason to think that the only important data point(s) on the temperature chart is the onset point of very cold weather, representing the injection of a mass of cold water. The only thing that we do not know is the actual scope of the event. It may last only one season and inject enough cold water to do the job. That would be my preference and supports the abrupt apparent temperature shift.

An alternative is an expansion of the flow rate of the respective currents that is sustained for years. The difficulty with that scenario is that we would have a slow climatic decline rather than the abrupt conversions that seem to have occurred. Of course we will never know for sure until it happens again in perhaps 400 years.

What I am saying is that instead of studying the warm years of the chart, we need to focus on perfecting our knowledge of when it became nasty cold. Remember, that the barbarians who invaded Gaul gathered at the Rhine and waited it for the river to freeze!

The rest of the data can be impacted by everything from Volcanoes to forest fires and who really notices if spring is a week early or not when the effect can be very local. Knowing that a sustained cold spell is not a normal event is very helpful in understanding our options and our temperature charts.

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