introduction

Temperature in Perspective

For a couple of million years, the earth has been going through a series of ice ages that blanket North America & Europe in glacial ice, sometimes 2 or 3 kilometers thick. These glacial actions wax and wane several times over the cycle, and each cycle has a period that is relatively ice-free, called the inter-glacial, and we are in one now.

Here is a chart showing the temperature for the current inter-glacial which we call the Holocene.

The cause of the glacial cycles is well known and due primarily to the various Milankovitch cycles. Yet these cycles are extremely long: 26 thousand years, 41 thousand years and 100 thousand years, and they all drive the 140 thousand year ice glaciation cycles. ...(Wikipedia)

However, all of these cycles are much longer than human lifespan and so is not something that can be experienced in a lifetime.

600M Years

How does our current climate compare to most of the planets history. Looking back, here is pretty much what the climate has been for the past 600 million years. Temperatures range from +12C to +22C and we are currently at the low point of that range. Apart from a couple of dips in temperature like our current situation, for the majority of the 600 million years, the temperature stood around +22C and the graph makes that look pretty much like the norm. However, something has been making the temperature drop slowly for the past 65 million years. Where our current temperature sits, down close to +12 is pretty close to as low as it ever gets and this is way below the norm for the planet. Just to restate that simple fact – our current temperature is way below normal for the planet.

Also worth noting are the current CO2 levels. It has rarely been this low in the planet's history. In fact it is historic lows. During the last glacial cycle it reached 180ppm which is getting very close to 150ppm which is considered the point where plants die off and all life on earth would perish, plants and animals.

400K Years

Now lets look at what the glacial cycles looks like by zooming into just the last 400 thousand years where we can very nicely see the last four glacial cycles.

400 thousand years is enough time to give us a sense of what each glacial period looks like and where we are in our current cycle.

A few things to note. The cycles are fairly regular but no two cycles are exactly alike. The time spent in the more “comfortable” ice free period is only about 20% of the cycle. Our current warm period seems to be past the halfway point yet so far, we experienced a relatively narrow range of temperature changes compared to previous cycles. All the scary man-made climate change occurs in the red blob at the far right where the temperature has been going up and down around the zero line for the past 10,000 years. It is pretty hard to see 100 years on this time scale as it would be the last edge of the blob but it is worth noting that it is well below the extreme temperature highs of previous cycles.

140K Years - Single Glaciation Cycle

(NOTE: This graph has a reversed date range compared to all the other graphs. On this one, present date is on the left and we go back in time as we move from left to right.)

There are few things worth noting which helps put our current situation into perspective. For one thing, the previous inter-glacial was quite a bit warmer than now, for most of it, and as much as 4 degrees C warmer than present.

The graph is showing us one complete cycle of an ice age so that we can understand what typically occurs. Starting at the right, and moving left, from 140 thousand years ago to 130 thousand years ago, the temperature rose from about -10C to +4C. This heralds the end of the glacial period and defines the inter-glacial. It is warm enough to melt away all the glaciers blanketing the earth, with the exception of the permanent ice cap in Antarctica and high altitude regions. We can pretty much consider any period above the -2 temperature line in the graph as the inter-glacial and anything below that as the glacial. As you can see, the inter-glacial is relatively short lived and by the 120 thousand year point, the temperature has dropped below the zero line and the long slow glacial period gets underway until about the 18 thousand year point where the temperature suddenly shoots up again. The next inter-glacial, the one we are currently in, started around 12 or 14 thousand years ago.

This indicates that our current situation sits inside the range of normal behaviour for an ice age. And if it were to warm another 4 degrees, then that would also be within the normal behaviour for a typical cycle.

The other thing that should be terribly obvious at this point, is that the temperature during the last 8,000 years have been relatively stable compared to the previous 140,000 years.

20K Years - Inter-glacial

20 thousand years captures the warming period of the current glacial period called the inter-glacial.

Here is another look at the same period with some of the interesting events highlighted. This graph is taken from a paper by Prof. Don Easterbrook.

The circled numbers on the graph refer to the sudden climate changes listed below:

(1) 15,000 years ago—a sudden, intense climatic warming (~12° C) caused dramatic melting of huge Ice Age continental glaciers that covered vast areas in North America, Europe, and Asia.

(2) A few centuries later, temperatures again plummeted (~11°C) and glaciers readvanced.

(3) 14,000 years ago—global temperatures rose rapidly (4.5°C) and glaciers retreated.

(4) 13,400 years ago—global temperatures plunged (~8°C) and glaciers readvanced.

(5) 13,200 years ago—global temperatures increased rapidly (~5°C) and glaciers retreated.

(6) 12,700 years ago—global temperatures plunged sharply (~8°C) and a 1000 year period of glacial readvance, the Younger Dryas, began.

(7) 11,500 years ago—global temperatures rose sharply (~12° C), marking the end of the Younger Dryas cold period.

(8) 8200 years ago—a sudden cooling interrupted the warm period of the past 10,000 years and was brought to a close by abrupt warming 150 years later. As shown on the graph, the temperature curve for almost all of the past 10,000 years lies above the level of present temperatures, indicating that most the past 10,000 years has been warmer than the present.

(9) 900–1300 AD—The Medieval Warm Period was a time of global warming when temperatures were slightly higher than present.

(10) 1300 AD to last century—The Little Ice Age was a time of cool climates during which glaciers expanded significantly and great famines swept Europe as a result of cold climate.

10K Years - Holocene

This chart shows our current inter-glacial period in the context of a complete glacial cycle. You can see how the temperature climbed out of the ice age and has been relatively stable for the past 11 thousand years.

This chart just appeared recently and it by far represents the context of our current situation better than anything else I have seen before. So take a quick look at the little red line at the right hand side of the graph. This represents the warming that has occurred during the last 150 years.

Yet another perspective of the last 10,000 years.

4K Years

350 Years - Central England

This graph was taken from a database of actual thermometer readings from over three centuries in Central England. Yet another perspective on climate change. Today is barely different than it was 350 years ago. Take a look at the summer temperature in 1650. 15.5? Take a look at the summer temperature today. 15.7? A slight warming trend over the long term to be sure, but just as we would expect, since we are in the midst of the warming portion of the glacial cycle. When the cooling trend starts it won’t be pleasant and it will last about 100,000 years.

129 Years - Global Warming

Let’s start by examining the land temperature record for the continental US. This is the gold standard for two reasons; it comes from an amazing network of stations sprinkled throughout the country going back over a hundreds years, and it comes from teams of trained meteorologists responsible for taking reliable thermometer readings. And so what does it tell us about modern times? As you can clearly see from the trend line, it has never been as hot as it was in the late 30’s.

Climate cooling trend continues! NASA data shows six year global trend for February is 0.43°C cooler! Why is the West shutting down pipelines & fossil fuel resources? pic.twitter.com/mXJnERZhXk

— Jack Eddyfier (@swcrisis) March 15, 2022

Climate Drivers / Cycles

Years	Cycle	Probable Cause
9.1	Lunar	Moons orbital cycle
11	Schwabe	Sunspot tied to Jupiter
22	Hale	Sun Magnetic field reversal
61	Yoshimura	Sun barycentre with Jupiter/Saturn
84-92	Gleissberg	Solar related to Uranus
120	Valasco	Grand Solar minimum
172	Landscheidt	Uranus/Neptune resonance
210-240	De-Vriess/Suess	TSI linked /2 resonance Uranus
934	Bond	Angular
1,470	Dansgaard-Oeschger	Unknown
2,300	Hallstatt/Bray	Solar
26,000	Milankovitch	Precession Earth axis
41,000	Milankovitch	Obiliquity Earth axial tilt
100,000	Milankovitch	Eccentricity Earth orbit

https://wattsupwiththat.com/2017/08/08/the-effects-of-the-bray-climate-and-solar-cycle/

11yr Sunspot cycle

60yr Barycentre cycle

65 year PDO cycle

Prof. Easterbrook has mapped out the periodic rise and fall of temperatures in Greenland during the last 500 years and found it matches pretty well with the alternating warm and cold periods of the 65 year Pacific Decadal Oscillation

Temperature changes in the Greenland GISP ice core show a regular pattern of alternate warming and cooling with a 25-30 year period for the past 500 years, very similar to the pattern shown by the Pacific Decadal Oscillation. – Prof. Don J. Easterbrook

He then goes on to make his own predications about our current situation that are remarkably different from the IPCC alarming predictions.

Figure. Projected global temperatures to 2050. Red line is the IPCC projected temperature curve from the IPCC web site in 2000. Blue lines are temperature curves based on projection of PDO for the past century and temperature patterns over the past 500 years. – Prof Don J. Easterbrook