and the 150MY Solar Cycle, W. Fiori, 28/4/2022
Average Global Temperature and the 150MY Solar Cycle
By: Walter Fiori
https://www.academia.edu/77856940/Average_Global_Temperature_and_the_150MY_Solar_Cycle
Discussion: https://www.academia.edu/s/ac34f54461
Date: 28 April 2022
Abstract
The earth is the recipient of the sun’s irradiation. It provides the earth with temperature variations that, in conjunction with the earth’s physical properties, create climate zones. The climate zones change, growing or reducing in area as the sun’s irradiation level changes and plate tectonics opens and closes seas and alters the size and position of land masses. The two forces work in unison to create or destroy life supporting habitats.
The overriding force is the warmth the earth receives from the sun. Without the sun’s warmth life as we know it would not exist on earth. The sun’s irradiation is not constant. It varies and several known cycles of increasing and reducing irradiation, such as those caused by changes in sunspot numbers, have been identified. However, there appears to be a sun cycle that the earth is subject to that lasts a far longer time. It is a cycle that lasts 150 million years that takes the earth from a low average global temperature (AGT) point to a high AGT point and then back again. The cycle is referred to as the 150MY Solar Cycle in this paper.
This paper is in two (2) parts. The first part (A) discusses the average global temperature and the 150MY Solar Cycle. The second part (B) discusses the effect the 150MY Solar Cycle had on the origination and extinction of the dinosaur genera of the Mesozoic Era.
Part 1
The concept of “Average Global Temperature” and the identification of the 150 million year solar cycle.
The term “Average Global Temperature” quantifies the average temperature of the earth throughout a year. A specific AGT, or a range of AGTs, can be used to identify a period of time when the earth was generally warm or cool, the length of time it took to reach a particular AGT and how long the warm or cool period lasted.
The method that shows the growth of the AGT is based on measures of surface land and ocean temperatures at many points throughout the world and statistically deriving a comparative value that is based on a consistent method of assessment of these measures. Differences between one year and the next are reported as the land/ocean surface temperature “anomaly”.
The anomaly by itself is not able to determine climate conditions pertinent to a specific AGT. A base was needed to create an AGT dataset that could be used for comparison. A value of 288º Kelvin (K) was set in a 2009 paper by Trenberth, K. The anomaly was added to this value in order to represent a value that is relevant to today.
In this paper the base AGT relevant to 2020 was reset to 292ºK in order to bring the data more in line with climate conditions that apply today when compared to the past. It follows the example of the AGT values noted by Scotese, C. R. (R2.01) on his AGT graph and, in particular, that the base temperature that differentiates a cool from a warm condition is 17ºC.
Historic AGT data is assessed by various alternative means. Values are set in terms of the method applied to the identification of past temperatures. Reference to two (2) different methods is made in this article.
Of importance to note is that, although the AGT measure is useful, setting it at either 288 or 292ºK is not necessarily correct. The AGT value is applied as a means to compare the AGT of one period to another in a simple and general concept in order to gain an insight of times when the earth provided greater or lesser comfort to life. The determination of earth’s comfort state are based on definitions of what warm or cool means drawn from studies of physical and life aspects of the earth.
Average global temperature scales
Data related to historic AGT information, “Average Global Temperature” graph, version ©2015 (R2.01), (Scotese, C. R., 2002) and article, Celestial driver of Phanerozoic climate? (R2.02) (Shaviv, N. J. and Veizer, J., 2003), in particular Figure 1 in their article, show that the earth experiences cycling periods of warm and cool climate. The authors each used a different method to arrive at this conclusion.
The values extracted from the AGT graph published by Scotese, C. R., was used throughout this analysis. The graph indicated a 2015 AGT of 18.8ºC.
AGT data published by others may differ in the manner of presentation. The Encyclopaedia Britannica’s article on the Cambrian Period (R2.03a), for example, states that the AGT of Cambrian times averaged 22°C and it refers to the AGT at the date of publication as about 14°C. There is a 4°C difference between the scales used by Scotese, C.R. and the scale used by the Encyclopaedia Britannica for both the Cambrian Period and today.
When referencing the peak AGT of the Permian Period, Scotese, C.R.’s graph shows it reaching an AGT of 28°C whereas the article on the Permian Period in the Encyclopaedia Britannica (R2.03b) omits a value for the peak temperature instead describing water temperatures in ranges that peaked at 32°C.
As water temperature is the major contributor to maintaining the AGT of the earth it would be reasonable to expect that the AGT would be representative of the water temperature indicated in the Encyclopaedia Britannica article.
To ensure that the 28°C determined for the time of the Permian Mass Extinction Event was suitably set it was necessary to investigate the measure in order to confirm that Scotese, C.R.’s data correctly represented the opportunity for the AGT to reach that temperature.
Determining the validity of the AGT scale
The method chosen to determine that Scotese, C.R.’s peak AGT in the Permian Period was representative of the possible/actual AGT was to investigate the highest annual average
temperature the sun can bring locations of the earth up to today, identify the reasons and compare the findings to the properties of the Permian Period.
The first step was to assess the properties of the earth today as it emerges from an ice age in a warming trend beginning with an understanding of regional climate conditions and properties that exist today.
Today there are considerable shallow seas about the dispersed land masses. Aridity includes the ice fields and sea ice deposits at the Polar Regions and the deserts of Central Asia (extending nearly to the East coast of Central Asia), parts of North and South Africa, the Arabian Peninsula and the Middle East, parts of North and South America, and Australia. There are tropical land areas in East, West and Central Africa, Central America, Southern Asia, South-East Asia and North Australia. Warm temperate climate zones exist on all continents. Cool temperate climate zones apply in northern Europe and Asia, in northern North America, at the base of South America and in the lower latitudes of Australia.
The sea is divided into defined areas known as the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, the Southern Ocean and the Arctic Ocean. The surface ocean waters about the equatorial and subequatorial regions (particularly in shallow and protected areas), the Mediterranean and Caribbean seas and the Gulf of Mexico, are warm but the sea water at the Polar Regions is below 0°C. Stratification of the waters in the oceans is evident and water temperatures lower the further below the surface the water lies and the further up the latitudes of the earth. An extensive system of ocean currents convey heat from warm locations to cool locations.
The present properties of the earth allows the earth’s equatorial and subequatorial regions to reach annual average temperatures (the average of the average high and average low temperatures measured at various locations) of 28°C, with some places marginally exceeding this temperature.
The islands that form the country of Kiribati (R2.04) (area of 811 km²) and Tuvalu (R2.05) (area of 25.9 km²) had supporting temperature measurements that substantiated the claims that their annual average temperatures exceeded 28°C regularly. Both these island countries are in the central Pacific Ocean close to the equator. They each lie within a group of reef islands that create a border about a shallow lagoon. Their coordinates are: Kiribati: 3.3704° S, 168.7340° W and Tuvalu: 7.1095° S, 177.6493° E.
The shallow water in the lagoon and the deeper ocean about them maintains the annual average day and night temperature with a variation, on average, of 5 to 6 degrees. However, as both are an island group with a small area of land, another example with greater land area was sourced to investigate. A suitable location was the island of Borneo (R2.06) in South East Asia.
Borneo is a large, established and inhabited island on the equator with a land area of 743,330 km². The island is encircled by seas that capture the sun’s heat - the South China Sea, the Sulu Sea, the Celebes Sea and the Java Sea. Three (3) of the seas are deep but the Java Sea is shallow with a mean depth of 46 metres.
The city of Pontianak is the only modern coastal city in the world that lies on the equator (coordinates 0°0′N 109°20′E), in the Indonesian part of Borneo. It is an excellent candidate to 3
assess the effect the sun has throughout the seasons on an island of significant area, with some protected shallow sea and shoreline, surrounded by seas of varying depths.
Pontianak’s climate data during the year was viewed on the Wikipedia article (R2.07), 2019. The source of the climate data in the article was noted as the World Meteorological Organisation (UN).
The data showed that Pontianak’s mean high/low temperature variation is 1°C. The highest and lowest daily mean temperatures are 28.2°C and 27.2°C respectively. The variation from high to low is 3.5%. This value is very close to the earth’s variation in distance from the sun between summer and winter, 147 and 152 million kilometres respectively, a variation of 3.3%.
The daily mean temperature variations at Pontianak shows that the equator receives a level of insolation from the sun that is directly related to the earth’s relative position during its annual elliptical orbit about it. The small variation of 0.2% between the two measures indicates that other environmental factors, possibly the surface heat of the shallow Java Sea and that the city is an urban heat island, are playing part in determining Pontianak’s seasonal conditions.
Pontianak has physical conditions that are different to the atoll and reef island countries of Tuvalu and Kiribati. It strongly indicates that the warmth gathered from the sun in the latter locations’ shallow lagoons elevates the annual average temperature to above 28°C.
Pontianak, bordered by deeper seas, is about 0.5°C less in its annual average temperature when compared to the two islands in the Pacific. It strongly suggests that deep seas about a large land mass keep the land area cooler.
The investigation of the 3 islands strongly indicates that the earth has the potential of reaching an AGT of 28°C, or a little above, if it became a consolidated land mass sited about the equator with sufficient areas of shallow seas surrounding it to capture and maintain the sun’s warmth.
Assessing the validity of the historic AGT
Land distribution data on Scotese, C.R.’s website and, in particular the video, Plate Tectonics, 540Ma - Modern World - Scotese Animation 022116b (R2.08), (2016), shows that the accumulated land mass in the late Permian Period stretched between the north and south poles. Pangaea was surrounded by a wide area of shallow seas until the late Permian/early Triassic Period.
By comparing the land and sea formation at the time of the Permian Mass Extinction Event to the annual average temperatures of Borneo today it strongly suggests that the earth had the physical properties suitable for the AGT to peak at about 28°C.
The Cambrian Period’s high AGT of 26°C, as indicated in the Paleomap Project AGT graph, suggests that the environment was detrimental to the origination and diversification of life. However, reporting AGT data does not mean that all the earth was sitting at the same temperature.
Referring to the AGT as being above 26°C suggests that the earth was considerably warmer than today. However, land distribution about the earth was different during the Cambrian
Period. Land was principally situated in the southern hemisphere, much of it below the Antarctic Circle, with some stretching past the equator. There were shallow seas surrounding the lands’ perimeter. There were also islands in the middle and upper latitudes of the southern hemisphere’s ocean and the northern hemisphere was nearly all ocean.
Land and ocean temperatures vary depending on where they are taken about the earth. Local temperatures are different to the AGT with some locations hotter and some colder. References to the habitat of earth’s early life during the Cambrian Period in the Encyclopaedia Britannica indicate temperature ranges at life’s habitat that differ to those indicated in the Paleomap Project AGT graph. The local temperatures of the waters and land masses at the lower latitudes of the southern hemisphere would have been cooler than the AGT of 26°C suggests.
The evidence of the explosive initiation of life on earth during the Cambrian Period clearly states that the local temperature where life flourished was in the range ideal for the origination, multiplication and diversification of life in the waters of that time. The shallower waters in the lower latitudes of the southern ocean would have been maintained at a warm temperature level for the many millions of years the AGT remained at a nearly constant 26°C varying only by a small and tolerable margin during the day/night cycle and between seasons.
The reported AGT during the Cambrian Period was different to the local temperature that prevailed about the southern hemisphere in the seas life inhabited. The measures are not in conflict and serve to explain that the differences are due to position and environmental parameters. It confirms that both the AGT of the earth, as noted on the Paleomap Project AGT graph, and the local temperatures at the habitats that supported life, as noted in the Encyclopaedia Britannica, are probable.
AGT during the Phanerozoic
and the 150MY Solar Cycle, W. Fiori, 28/4/2022
Figure 2.1 shows the AGT graph from the Paleomap Project website, graph A, converted to a
linear base, graph B. Both graphs represent the movement of the AGT during the last 600MYs.
Figure 2.1, graph B, shows that earth’s AGT cycles from cool to warm and back to cool during a 150MY Solar Cycle and that:
Each cycle has unique AGT peaks and lows.
Each cycle reaches a peak AGT above 24°C.
The low temperature point varies but every second cycle dips below 14°C.
In any one cycle the peak AGT in a warming trend is reached faster than the low point in a cooling trend.
There were three (3) 150MY Solar Cycles during the Phanerozoic Eon. A fourth commenced in the Late Precambrian and completed in the Late Ordovician Periods.
Each 150MY Solar Cycle has two (2) principal trends - one warming and one cooling. As it progresses from a bottom low point in a warming cycle it enters a warm phase, above 17°C, and remains above 17°C, despite a change in the warming trend to a cooling trend, for about 120MYs. The norm for the earth is to be warm. It has been warm for nearly 80% of the last 610MYs.
The earth is normally free of ice fields while in a warm phase. This was the case in all except one occasion in the Phanerozoic Eon. An ice field formed at the South Pole in the late Devonian-early Carboniferous Periods. The formation of the ice field coincided with the Devonian Mass Extinction Event (R2.09). The circumstances that caused the ice cover, and possibly contributed to the mass extinction, lasted a relatively short time. It had little to no effect on the cooling trend the earth was following and the ice cover did not persist past the early Carboniferous Period. It is most likely that ice deposited onto land was restricted to the southern Polar Circle and the cold had little to no affect anywhere else on earth.
AGT and the 150MY Solar Cycle, W. Fiori, 28/4/2022
The 150MY Solar Cycle has a secondary cycle of deep-cooling that occurs about every 300MYs. The secondary cycle appears to alternate the intensity of the cold phase of the cycle between shallow-cool periods lasting a short time and deep-cool periods lasting a long time. The AGT of the low point of the shallow-cool phase, between two deep-cool phases, may or may not dip below 17°C. Significant ice age conditions occur during deep-cool phases.
There have been three (3) deep-cool phases during the last 610MYs:
The Late Precambrian Period.
The Late Carboniferous-Early Permian Periods.
The Late Cenozoic Era.
The deep-cool phases have caused the earth to endure AGTs of 14°C and below for a total of 52 of the last 610MYs, 8.7% of the time assessed. A fourth ice age in the late Ordovician Period, the Andean-Saharan, has been listed amongst the ice ages but its transit below the AGT of 17°C lasted only 6MYs and it did not advance below 14°C. Ice accumulated at the southern Polar Region but not to the extent of the deep-cool phases associated with the Cryogenian, Karoo or Quaternary Ice Ages (R2.10) .
A deep-cool phase drives the AGT below 14°C. Pack ice fields form at altitude, on either the southern or both Polar Regions’ land and subsequently on the Polar Region’s sea. The bitter cold about the effected Polar Region persists for many millions of years.
In a natural recovery from an ice age, the earth starts to warm slowly. As the pack sea ice melts it allows the rate of warming to accelerate. Once all the sea ice is melted the warming rate increases until it reaches the cycle’s peak AGT. It takes a natural warming recovery tens of millions of years to melt the ice fields and have the earth return to a warm state at, and above, an AGT of 17°C.
The deep-cool phases appear to have two cycles within them. However, because of lack of data, it is difficult to state whether this is a recurrent situation as only one (1) deep-cool phase example in the last 610MYs is a complete cycle. However, data indicates that:
The deep-cool phases of both the Carboniferous-Permian Periods and the Cenozoic Era had two (2) low points and two (2) rebounds to a warming trend.
In both cases the rebound from the first cooling trend did not reach the AGT of 17°C before turning to a cooling trend that took the AGT to, or below, the first low point.
The second low point was the end point of one 150MY Solar Cycle and the beginning of another.
The similarities between the Karoo and Quaternary Ice Ages are:
Their trek to the low AGT point occurred in two stages.
The first stage of the Karoo Ice Age lasted 20MYs and the second stage 40MYs.
The first stage of the Quaternary Ice Age had a duration time of 18.9MYs. The second stage is still in progress but is impacted by anthropogenic activity.
The low point of the second stage of both ice ages was the beginning of a warming trend.
Today the earth is climbing out of the low point of the last completed 150MY Solar Cycle that ended 2.1MYA. The earth is at the early stages of a fifth 150MY Solar Cycle.
and the 150MY Solar Cycle, W. Fiori, 28/4/2022
It is not possible to predict particular future points of AGT from the cycle’s current AGT point. The randomness of the deviations from the principal trend and their varying intensity only allow the following predictions to be made:
A 150MY Solar Cycle takes the earth’s AGT from one low point to the next.
Within the main solar cycle, there is a warm period when the AGT climbs from 17°C to a peak point (an AGT above 24°C) and then lowers back to 17°C in a time frame of 120 +/- 5MYs.
The earth’s next peak AGT will be reached in 65 to 70MYs.
The AGT has the possibility of reaching a maximum of about 28°C if the continental land masses merge together during the next 130 to 140MYs.
The current solar cycle, due to end in about 148MYs, will terminate in a shallow-cool phase.
Aspects dealing with the sun’s irradiation, its variation and the effects they have on the earth are described in the 2021 article, Variability of the Total Solar Irradiance (R2.11), published on academia.edu.
Warming trends
The warming trend of a 150MY Solar Cycle causes all of the earth, the atmosphere, the land and the sea to warm. Minor glitches in the warming trend may be caused by movement of the continental plates increasing or reducing the land mass, lifting and lowering seabeds and by covering surfaces by debris that changes the reflectivity of the earth. The earth’s albedo effect may be altered by many natural circumstances. Glitches may also occur by influences external to the earth’s environment.
Figure 2.2 shows that there was little change in the distribution of the land masses about the earth from 540 to 440MYA.
Land, mostly in the southern hemisphere, was slowly moving northward. The sea occupied most of the surface area of the northern hemisphere. The land started consolidating in the northern hemisphere 400 to 380MYA.
AGT and the 150MY Solar Cycle, W. Fiori, 28/4/2022
Figure 2.1, graph B, shows that the warming phase that allowed the earth to climb out of the low temperatures of the Cryogenian Ice Age began in the Precambrian Period and the AGT reached 17°C about 578MYA.
40MYs later, in the Cambrian Period, the AGT surpassed 25°C then climbed a little further and sat at about 26°C for about the next 80MYs. The temperature began to drop during the mid-Ordovician Period. It lowered to about 14°C before the warming trend of a new 150MY Solar Cycle increased the AGT to about 21°C as it entered the Silurian Period, 440MYA.
The local temperatures of equatorial and sub-equatorial land reached well above the 26°C that the AGT of that time indicates. Daily land temperatures varied in accordance to the season and to the strength of the insolation as it combatted the atmosphere, clouds and the albedo effect.
Carbon dioxide concentrations, as shown on Figure 2.2, were up to 7 times greater than they are today (406ppmv, 2016). Water vapour must also have been at a high concentration as its atmospheric concentration is directly related to the AGT. Dissipation of the sun’s energy at night occurred as it does today.
There were no densely foliaged and long stemmed plants on land to capture the heat of the sun and consume the carbon dioxide in the air. Fossil evidence of life on land in the Cambrian Period is mainly of algae and fungi. They must have been as important to the existence to life then as they are today.
The sea was the medium that maintained the constant average temperature of the earth for the length of time the earth was warm. The biosphere cooled to the temperature of the upper strata of the sea in the absence of the sun’s light irrespective of the temperature reached while in the sun’s light, moderating only slightly through the seasons.
It is therefore possible to conclude that in the Cambrian Period the warming trend of the 150MY Solar Cycle warmed the earth to an AGT of about 26°C and the practically constant temperature was maintained because the sun’s insolation had equivalent heat dissipation to the universe at night.
Cooling trends
The path to global warming is straightforward if considering a start point that is cooler than the eventual peak temperature reached. It is more difficult to determine what would cause the earth to suddenly cool down and continue cooling to possible ice age conditions.
Several of the earth’s properties can be considered but none of the current theories explain the long periods of time when earth is in a cooling phase nor what drives the AGT below 17°C and to the point of creating periods of rapid cooling, glaciation and the development of sea ice fields.
Figure 2.2, map C shows the land distribution 460MYA during the time of the cooling trend that began about 472MYA. There is little difference in the position of land masses in Figure 2.2’s map C when compared to maps A, B and D. The atmospheric concentration of carbon dioxide remained above 2300ppm throughout the 100 million year period covered by the maps. It is difficult to explain what caused the cooling trend based on the earth’s land and sea distribution or the concentration of atmospheric carbon dioxide.
It must be a significant and persistent influence that causes the 150MY Solar Cycle to happen. The solar cycle’s repetition identifies it as being part of the dynamics of the Solar System. The transition to a cooling phase appears to be a sudden entry into an environment that diminishes the intensity of the insolation that reaches the earth’s surface.
The reduced intensity of the insolation is only slight but sufficient to cause the atmosphere and the oceans to slowly dissipate their stored heat and cool down the earth until the circumstance that drives the atmosphere and oceans to cool finishes. During the 150MY Solar Cycle greenhouse gases may control the rate of heat dissipation to the universe but the amount of time the cooling trend lasts cannot not stop the earth from reaching AGTs below 17°C.
Some of the cooling trends lasted about:
80MYs from the peak temperature point of the Devonian to the first low point in the Carboniferous Periods at an average rate of change of -0.15°C per MYs.
84MYs from the peak temperature point at the beginning of the Triassic Period to the low point in the Middle Jurassic Period at an average rate of change of -0.11°C per MYs.
75MYs from the peak temperature point from the Late Cretaceous Period to the low point about 2.1MYA at an average rate of change of -0.18°C per MYs. There were two warm rebounds during this time but they are both considered as anomalies of the cooling trend because of their particularly short duration.
Deviations to the warming and cooling trends
The 150MY Solar Cycle is subjected to deviations that abruptly affect the principal warming and cooling trends that:
Can cause significant changes to the principal trend’s magnitude and to its direction.
Occur randomly and spontaneously superimposing themselves onto the natural solar cycle.
Last for varying times up to several MYs.
The principal trend absorbs the shorter-term deviations and modifies the warming/cooling action it was following accordingly. When the cause of the deviation ends the trend returns to its pre-destined path, returning to the point it would have been at had it not been interrupted.
The data points to produce Figure 2.1, graph B, define 126 different trends during the last 610MYs. Of the 126 trends there were three (3) when the earth had an almost constant AGT. The first of the three (3) started in the Cambrian and finished in the Ordovician Periods. The AGT of about 26°C lasted 51MYs. Life in the sea originated and diversified during this time in a temperature maintained environment. The other two (2) periods of constant temperature lasted 5MYs. Life progressed with no particular distinguishing environmental incidences during this time.
Of the remaining 123 trends:
60 were cooling trends that lasted a total of 268MYs.
63 were warming trends that lasted a total of 284MYs.
The average duration of a cooling trend was 4.46MYs.
AGT and the 150MY Solar Cycle, W. Fiori, 28/4/2022
The average duration of a warming trend was 4.51MYs.
The longest uninterrupted warming trend lasted 19MYs.
The longest uninterrupted cooling trend lasted 17MYs.
The data indicates that short term warming and cooling trends that occur within the major warming and cooling cycle trends last for nearly the same amount of time.
Significant warming trends
The earth’s AGT fluctuates constantly during its 150MY Solar Cycle whether in a warming or cooling trend. Their rates of change were considered and the more significant ones (trends greater than 0.3°C per MYs) during the last 600MYs are listed in Table 2.1.
Table 2.1 - Significant warming rates in the last 600MYs
Note: The data presented in Table 2.1 must be considered within the constraints of the statistical methods applied to determine values with a high degree of confidence. The further back in time the data represents the greater is the degree of uncertainty and statistical methods are used to smooth the values to produce data with a high degree of confidence. The smoothing method may eliminate distant past short term events that are statistically viable when a greater number of data points, as would apply in the recent past, are considered.
The data shows that the warming trends of the Cenozoic Era, up to 300,000 years ago, are more intense but shorter lasting than the warming trends that occurred 600 to 400MYA and 400 to 200MYA.
The Cenozoic Era’s higher intensity rates of warming could be the reason why the Solar Constant is at 1367W/m² today and why the current rate of natural warming has advanced, on average, at more than 4 times the average of the last 610 million years.
In the last 610 million years, not including the last 300,000 years, there have been thirteen (13) occasions when the rate of change of the average global temperature trend was equal to or greater than +/- 1°C per million years. Eight (8) occasions were of warming (as shown in Table 2.1) and five (5) occasions were of cooling.
Of these, only two (2) warming rates were more than 1.8°C per million years and only one (1) cooling rate was less than –1.8°C per million years. They all occurred in the Cenozoic Period. Of the 13 rates of change noted previously, 9 lasted 600,000 years or less, 3 lasted 2 million years and 1 lasted 3 million years. The total time the 13 exceptional rates of change lasted was about 12.2 million years in the total of the 610MYs assessed (about 2% of the time).
All other rates of change during the last 610MYs, either cooling or warming, were well below 1°C per million years. The normal rate of change for either a warming or cooling trend causes the average global temperature and the climate of the Earth to change slowly over many millions of years.
The variations in the average global temperature, and the consistency of the cycle time, of the last 600 million years indicates that the probable cause has to do with the variability of the heat energy output from the sun; the sun’s Total Solar Irradiance (TSI).
It appears that the sun’s TSI volatility has progressively increased during the last 610MYs.
The earth would have continued to warm from an average global temperature of 14°C, 12,000 years ago, to reach an average global temperature of 15.3°C in 1MYs time if the natural warming trend was maintained at the rate of 1.3°C/MYs by a TSI of 1367W/m2 Today’s average global temperature would be a little over 14°C.
Trend deviations of the Cenozoic Era
During the Cenozoic Era the 150MY Solar Cycle completed its 120MYs of warmth and reached the AGT of 17°C 33.2MYA. The earth entered a cooling stage and the AGT fell from that time, despite some deviations about the trend, until the cooling trend took the AGT to the low of 11.3°C, 2.1MYA.
The Pleistocene glaciation took hold and ice accumulated and compacted. The process of glaciation first started on the Antarctic land about 33MYA and then, about 25 to 30MYs later, at the Arctic. The area the ice fields occupied grew larger and ultimately created extensive Antarctic and Arctic land and sea ice fields.
The cooling trend that took the earth to the low point of the Quaternary ice age began 77MYA and ended 2.1MYA. The red trend line on Figure 2.1, graph B, shows that, on a straight line basis, the earth cooled at a rate of -0.17°C per MYs from the peak temperature 77MYA to the low of 2.1MYA.
AGT and the 150MY Solar Cycle, W. Fiori, 28/4/2022
However, the Cenozoic was not a time when the decline in the AGT was constant. There were 39 deviations from the cooling trend as shown on Figure 2.3.
The last portion of the Pleistocene Epoch had the fastest decline in the AGT. It decreased from 13.3°C to 11.3°C in 0.5MYs at an average rate of4°C per MYs, bottoming 2.1MYA, but peaked at a rate of -7.5°C per MYs between 2.3 to 2.1MYA.
The 150MY Solar Cycle ended 2.1MYA and the trend changed to warming. It continued in a natural warming path that persists today. A series of interglacial periods during this time, linked to the Milankovitch Cycles, swung the AGT about the natural warming trend. The interglacial periods had a frequency of 41,000 years up to about 1MYA and then cycled each 100,000 years until the interglacial periods ended about 12,000 years ago.
The Cenozoic Era holds the record for both the lowest temperature reached (11.3°C) and the fastest rate of natural warming, 8.75°C per MYs (the Palaeocene-Eocene Thermal Maximum (R2.12) about 55 to 54 MYA), during the Phanerozoic Eon, up to 300,000 years ago.
From the low AGT point 2.1MYA the AGT climbed steadily to 14°C 12,000 years ago, the beginning of the Holocene Epoch, at a rate of about 1.3°C per MYs despite the series of Milankovitch Cycle induced interglacial periods.
The Holocene Epoch is associated with the warming of the earth after its exit from the last interglacial period and the rise of Homo sapien civilisation.
The calculated rate of warming from 300,000 years ago to today is about 17.7°C per MYs. However, the major part of the rise happened in the Holocene and particularly after the Industrial Revolution.
Part 2.
The impact of the 150MY Solar Cycle during the Age of Dinosaurs
Introduction
Dinosaurs (R2.13) are unique genera that existed in both the northern and southern hemispheres during the Mesozoic Era’s 3 periods - the Triassic (250 to 200MYA), the Jurassic (200 to 146MYA) and the Cretaceous (146 to 65MYA).
The climate developed by the 150MY Solar Cycle during the Mesozoic was warm, not declining below an AGT of 18.4°C. The swing of the 150MY Solar Cycle causing the AGT to reach a peak of 28°C in the early Triassic and 24.2°C in the late Cretaceous. Cooler climate developed in the Jurassic and some habitats were driven into climate and environmental conditions not able to support the existence of dinosaurs.
and the 150MY Solar Cycle, W. Fiori, 28/4/2022
Dinosaur fossil records show their distribution throughout the continents together with each genus’ time of existence, location of existence and genera longevity within the three (3) periods of the Era. A sample of dinosaur genera from these records was tabulated and graphed to show the timing of originations and extinctions during the Mesozoic Era.
The first dinosaur genera originations were in the continents of South America and Africa. Their origination are timed to the mid-Triassic Period. A little later dinosaur genera originations began in the continents of the northern hemisphere. The genera were subjected to varying climatic conditions that caused mass extinctions at the end of each Period of the Mesozoic Era. Dinosaurs existed on earth for about 165MYs. They became extinct about 65MYA.
Their origination in a warm temperate climate zone and their survivability in warm temperate and tropical climate zones points to the possibility of their evolution from endothermic life.
The 150MY Solar Cycle has a long history of its association with plate tectonics and their combined effect on life. The influence that the dual aspects of climate change and continental drift had on the dinosaur genera of the Mesozoic Era will be discussed in a later submission.
Climate of the Mesozoic Era
Figure 2.4 shows that the climate and topography about the earth changed constantly during Mesozoic Era as it progressed through the sun’s 150MY Solar Cycles.
Major developments were that Pangaea separated into the individual continents and the Atlantic Ocean formed in the space between the South American and African continents and the North American and European
The life that survived the Permian Mass Extinction Event existed in the available habitats in the warm temperate climate and tropical climate zones and remaining shallow seas at the beginning of the Triassic Period.
These sparse locations of the earth provided environmental conditions that supported life through the demanding time of the late Permian Period and into the Triassic Period.
The Triassic Period began about 250MYA. The AGT at the start of the Period was about 28°C. It was also when the cooling phase of the 150MY Solar Cycle began. The AGT fell 3°C, to just above 25°C, in the first 10MYs of the Triassic Period as the earth cooled.
Much of the earth was arid 240MYA as shown on Figure 2.4, map 240MYA. The arid climate was not conducive to harbouring life or supporting originations of genera. The immense area of aridity that centred about the Equator effectively separated the northern and southern hemispheres’ warm temperate zones.
Tropical zones above large bodies of water existed throughout the Mesozoic Era and extended into the shallow waters and shorelines of continents about the equator until the Atlantic Ocean began to form (Figure 2.4, maps 120 and 80MYA). Once the Atlantic Ocean formed a tropical climate spread across the equator over ocean and land as shown in Figure 2.4, map 80MYA.
The rate of decline in the AGT slowed from 240MYA to about 210MYA. Warm temperate and tropical climate zones expanded in both hemispheres as the earth cooled. The changing climate increased the opportunity for suitable habitat for plant and animal life to form. Life was able to establish itself in the stable land in the warm temperate zones of the South American and African continents as shown in Figure 2.4, maps 240 and 210MYA
The northern hemisphere was delayed in its opportunity to host life. The climate offered life an opportunity to establish itself but life was unable to grab onto the opportunity in the locations it offered. Warm temperate zones and extensive tropical areas formed in the northern hemisphere but much of the warm temperate zone was in the latitudes of the Arctic Circle and significant sea level changes caused habitat instability.
The AGT continued its decline throughout the Triassic Period at a slow but accelerating pace and forced climate change to areas about the earth. Stable land with suitable climate became available in the northern hemisphere in the late Triassic Period and dinosaurs originated.
Dinosaurs survived at the locations of their origination until the Triassic mass extinction event when dinosaur genera worldwide, except two (2) genera in Europe, were decimated.
The Jurassic Period began 200MYA. The AGT was about 24°C. The arid climate zone, less in area than it was 50MYs earlier, still occupied an extensive area. The climate conditions changed as the AGT dropped steadily between 210 and 180MYA. The warm temperate zones moved to lower latitudes and the tropical zone expanded. The changing climate zones pushed the arid zone further towards the equator as shown in Figure 2.4, map 180MYA.
The cool temperate climate that earlier formed about the North and South Poles increased in area as the AGT approached the low of 18.4°C, 165MYA. The area of aridity expanded as the tropical climate zone shrank. The warm temperate zone was squeezed between the arid and cool temperate climate zones.
The arid conditions that slowly, but steadily, increased about the equator and sub-tropical latitudes changed habitat conditions during that time and life in the habitat changed with it. Life was driven from locations whose climate deteriorated and other locations opened to life. Life occupied potential new habitat after a time lag.
AGT and the 150MY Solar Cycle, W. Fiori, 28/4/2022
The cold temperate conditions about the Polar Regions persisted into the Cenozoic Era changing the area they covered as the AGT increased and decreased through the 150MY Solar Cycle as shown on the maps of Figure 2.4.
Life was faced with the challenges of climate change throughout the Mesozoic Era. The area the different climate zones covered expanded and contracted in unison with the changing AGT and surface topography.
The low AGT point 165MYA signalled the closing of one 150MY Solar Cycle and the beginning of a new cycle. The AGT started to rise and continued rising (with only a small interruption about 90MYA) peaking at 24.2°C about 76MYA before declining to about 22.3°C at the time of the K/T Mass Extinction Event.
The land formation changed in the early Cretaceous Period. The South American and African continents and the North American and European continents separated and the Atlantic Ocean was created.
The land area of the Triassic and Jurassic Periods, previously surrounded by one body of ocean, now had two main bodies of ocean and a third that was formed in the space between the west coast of Africa, the southern coast of Asia and the eastern coast of the Australian and Antarctic continent.
The oceans changed the climate and environmental conditions about the earth and allowed a tropical climate to form about the equator on sea and land. The area the tropical climate occupied divided the expansive aridity that persisted about the equator previously. Part of the arid zone drifted south and part drifted north as shown in Figure 2.4, map 80MYA. Parts of North Africa were now in a tropical climate zone and shared a tropical climate with what is now Southern Europe.
The Pacific, Atlantic and Indian Oceans were well formed by the Eocene Epoch and all covered a substantial area of the earth. These vast expanses of water were able to maintain a warm and moist climate about the equator to today.
Continental plate movement affected landform stability significantly during the Mesozoic Era. During its 185MYs duration continental drift changed the land from the singular mass that stretched from the North to the South Poles at the beginning of the Triassic Period into individual continents by the end of the Cretaceous Period, as shown in Figure 2.5.
The peak AGT of 28°C and the enormity of the land mass, with ocean about its perimeter at the beginning of the Triassic Period, maintained the bulk of the land mass in a state of aridity as shown in Figure 2.4, map 240MYA that persisted about the equator
The land formation and persistence of the arid climate throughout the Mesozoic Era states that dinosaur in the southern hemisphere originated independently from those of the northern hemisphere as migration from one hemisphere to the other was not possible.
Dinosaur origination and extinction
Life of the Palaeozoic Era diversified wherever suitable habitat formed. But the life that entered the Mesozoic Era was the remnants of life after the Permian Mass Extinction Event. The dinosaur genera of each hemisphere emerged as genera specific to the habitat of the hemisphere of their spawning. Dinosaurs diversified and multiplied in the climate zones and habitats conducive to their survival needs throughout the Mesozoic Era only to be made extinct about 65MYA.
The time and place of origination of dinosaurs was assessed from a sample of 353 dinosaur genera in a population size of 1122 genera sourced from Wikipedia (R2.14) data, timelines and lists, by continent. The data was summarised by time and location of origination of dinosaurs during the Mesozoic Era as shown in Table 2.2.
The “Bridging” columns in Table 2.2 show how many of the dinosaur that originated in the completed Period continued to exist in the following Period. Note that the extinction of any unique dinosaur could have occurred prior to the end of the Period in which they originated.
All but three (3) dinosaur genera in the sample that survived up to each of the Period boundary became extinct at each Period boundary’s mass extinction event. The survivors were all European originations - two (2) survived the Triassic mass extinction and one (1) survived the Jurassic mass extinction.
The sample indicates that the first dinosaur originations were in South America and Africa in the Middle Triassic Period. Dinosaurs originated in Europe in the late Triassic Period. Originations proceeded slowly during the Triassic Period. By the Late Triassic Period originations occurred in all continents except Australia and Antarctica.
The mass extinction at the end of the Triassic Period decimated the dinosaur genera but swift recovery of originations in the early Jurassic Period in all continents, including Australia and Antarctica swelled global existences as the AGT decreased from 24°C to 22°C.
The mass extinction event at the end of the Jurassic Period once again heavily impacted the dinosaurs but the genera recovered, slowly at first, in the Cretaceous Period.
The Cretaceous Period was the most dinosaur genera productive of the Mesozoic Era. 202 dinosaur genera, 58.2% of the sample of 353 dinosaur genera, originated during this period. The majority of the originations were in the northern hemisphere. Overall, Asia and Europe had the most originations during the Mesozoic Era. Each had 73 (20.7%) dinosaur originations in the sample.
No unique dinosaur existed throughout the whole of the Era. Each dinosaur type seemed to come and go, some lasting from a few hundred thousand years to others that lasted about 10MYs.
Percentage originations of Dinosaur genera
The Dinosaur Origination and Extinction data, in Table 2.2, was retabulated and graphed in order to visually gauge the effect changes in climate (through either changes in the level of insolation or habitat alterations caused by tectonic activity) had on the dinosaur genera.
The data lines on Figure 2.6 show the variability in dinosaur originations and extinctions and a representative visualisation of percentage originations, a method adopted from the work of Cosgrove, J. (R2.15), which indicates the extent of origination activity when directly compared to extinction activity.
Dinosaur originations began in the early part of the mid-Triassic Period. The AGT was about 25°C. Much of the earth’s land was still overcome by aridity, as previously described.
The warm temperate zone that settled in the upper latitudes of Pangaea to the South Pole abutted a large arid zone to its north and an ocean on its western shore. Local weather patterns generated by the proximity to both the arid and ocean environments created varying microclimates throughout the warm temperate zone that gave rise to habitat suited to land animal life.
Carbon dioxide values fluctuated wildly during the Mesozoic as shown in Figure 2.7. The Triassic Period began with a high 28°C AGT and an
and the 150MY Solar Cycle, W. Fiori, 28/4/2022
atmospheric concentration of carbon dioxide of less than 250ppm. The carbon dioxide concentration grew steadily as the AGT declined throughout the Triassic reaching a peak of about 1,100ppm 10MYs before the end of the period.
The decline took it past the Triassic extinction event about 200MYA and into the early Jurassic Period. The mid-Jurassic saw a high level of carbon dioxide atmospheric concentration as the 150MY Solar Cycle was taking the AGT to its low point about 165MYA.
Another burst of carbon dioxide increased the atmospheric concentration as the AGT began to climb in the warming part of the 150MY Solar Cycle peaking to nearly 1,500 ppm in the early Cretaceous Period. The decline of the atmospheric concentration of carbon dioxide began in the early Cretaceous and continued, with a bump a little later, to the end of the Period while, at the same time, the AGT climbed to its peak about 15MYs before the Period ended. There was no association between the AGT and the atmospheric concentration of carbon dioxide throughout the whole of the Mesozoic Era. Any possible relationship was purely coincidental.
Figure 2.8 shows that the stable land in the continents of South America and Africa had local climate and environmental conditions suitable origination of dinosaurs. Dinosaurs group originated in the habitat provided by the temperate climate of the stable landa climate they appear to have had a preference for.
Dinosaur genera first originated about 230MYA. The dinosaur Eoraptor (R2.16) (231 to 228MYA) is one of the earliest known dinosaurs. Its fossils were discovered in north-western Argentina, at the location shown as a red dot on Figure 2.8.
Originations of dinosaur genera were greater than extinctions when the earth lay in the AGT range of 19 to 23°C and stable land was situated at latitudes where the temperature range created suitable and sustainable habitats for them.
Dinosaurs were dependent on the climate conditions prevalent at their habitat as dictated by the prevailing AGT and the latitude the land resided in. If the AGT remained stable, but the land moved from the latitudes that provided the preferred climate conditions, the situation for them changed.
As the AGT dipped below 19°C in the middle Jurassic Period it changed the climate conditions of several of the dinosaur habitats. Originations continued where habitat and
climate conditions were favourable but extinctions increased dramatically greatly outweighing the number of originations as habitat and the life it supported succumbed to the cooling climate.
The cooling trend ended about 165MYA and it began to warm. Originations increased and extinctions reduced as it warmed and the AGT reached and surpassed 19°C. Life was on the move again gaining much of its losses suffered during the cooler period. Growth continued until the AGT reached a point where it began to affect habitat, and the life at the habitat, once more.
From the middle to the late Cretaceous Period the AGT climbed steadily and surpassed 23°C. Climate changed as it became warmer. Once again locations habitable to the dinosaur became uninhabitable. Originations plummeted and extinctions climbed from then to the Late Cretaceous; only recovering in the very Late Cretaceous when the AGT lowered to below 22.5°C. This time saw another boom of dinosaur originations that continued until the K/T mass extinction event.
Climate conditions at dinosaur habitats
Figure 2.6 shows that dinosaur genera were susceptible to either a reduction or an increase in the AGT that changed the local temperatures and climate conditions beyond the tolerance of the life in the habitat. It indicates that dinosaur genera were dependent on a habitat that provided a climate with a local temperature range necessary to maintain their life’s primary sustenance and survival needs.
There are a number of issues that have emerged when assessing the life and conditions of the Mesozoic Era, in particular the physiology of the Superorder Dinosauria when considered in terms of the climate of the habitat they occupied. Dinosaur genera were able to tolerate both a tropical and a warm temperate climate within the boundaries of their physiology.
The origination of the dinosaur genera began in the warm temperate climate of the early Triassic Period. A warm temperate climate is a state of climate where seasons are prevalent. There is a summer, autumn, winter and spring each with its own local temperature variation and particular environmental conditions. A warm temperate zone during the Mesozoic Era must have had the same type of local temperature variations through the seasons as happens today. The AGT was higher than today during the major part of the Mesozoic Era and the warm temperate climate zones would have been pushed up the latitudes the warmer it became.
The continents where the first dinosaurs originated, South America and Africa, were both contained in the stable land mass of Pangaea as shown in Figure 2.8. They were sited lower in the southern latitudes than they are today. During the early to mid-Triassic Period the warm temperate climate zone in the southern hemisphere began a little above the 60th parallel and extended to the 90th parallel. It abutted land immersed in an arid climate to the north. There was a distant and inaccessible tropical climate zone about the equator mainly over water. There was only a small corridor of land available to life dependent on the day/night cycle.
The dinosaurs that originated in these continents had to be able to be sustained by the food source that established itself in the habitat and tolerate the change in seasons. It may well have been warmer overall, as the AGT of that time was about 25°C, but the swing in local temperatures in the warm temperate zone, caused by changes in the seasons, dictates an annual period of warmth followed by a period of cool, something in the order of the swing in temperature experienced in the mid-coastal area of Eastern Australia today that is not in the sub-tropics.
The many genera of dinosaur that originated in the warm temperate climate zones about the earth throughout the Mesozoic Era would have had to tolerate distinct seasons with peaks and lows in local temperature. Tyrannosaurus Rex, for example, inhabited the midlands of the North American continent during the Cretaceous Period when the climate was warm temperate as shown in Figure 2.9.
Tyrannosaurus Rex have been found in the Canadian states of Alberta and Saskatchewan and in the U.S.A. midland states of Montana, North Dakota, South Dakota, Wyoming and Colorado with possible habitation of the genera in the north of Texas and New Mexico.
All the above states of Canada and the U.S.A. had a warm temperate climate during the lifetime of the Tyrannosaurus
The AGT 67MYA was about 23°C but the latitudes that the warm temperate zone occupied, particularly about the 60°N latitude, would have been subjected to seasonal temperature variations that are normally outside of the tolerance of reptiles unless they hibernate.
Winter months at an upper latitude’s warm temperate zone can be harsh and several modern animals hibernate to survive. In 2011 the Monash University (R2.17) investigated the hibernation aspect of Australian dinosaurs of the early Cretaceous. Parts of Australia and Antarctica were in a warm temperate climate zone and above the Antarctic Circle at that time and there were several originations of dinosaurs in both locations. The study reported that it was unlikely that Australian dinosaurs hibernated.
The existence of Tyrannosaurus Rex, and the dinosaurs it preyed on, in the warm temperate climate at latitudes as high as the Arctic Circle points to the group having properties that allowed them to survive in the swaying temperature ranges of a warm temperate climate.
The most successful method for terrestrial animals to survive a constantly varying temperature range is endothermy. A constant food source is the main prerequisite for endothermic life but insulating properties such as fur or feather coverings and the ability to store fat add opportunity for life to survive in variable weather conditions. It suggests the possibility of climate specific species originating at different latitudes of their habitat. A situation that may also have applied to their prey. These are also the properties shared by the mammals and birds that have spread throughout all the earth’s climate zones today.
Dinosaurs’ initial South American origination in a warm temperate zone, their ability to survive in warm temperate zones as wide in latitude as shown for Tyrannosaurus Rex and the physiological structure of theropods and sauropods point them to be of a faunal order distinct from reptiles. It suggests strongly that they evolved from an endothermic ancestor and had the prerequisite insulating qualities that many animals able to endure a significant variation in local temperatures without hibernation have today.
…
References
R2.01 Scotese, C. R., 2002 http://www.scotese.com, (Paleomap website). average global temperature graph at http://www.scotese.com/climate.htm
R2.02 Shaviv, N. J. and Veizer, J., Celestial driver of Phanerozoic climate? Published in GSA TODAY, Vol 13, No.7, July, 2003.
R2.03a Johnson, Markes E., Robison, Richard A. and Crick, Rex E. "Cambrian Period". Encyclopedia Britannica, Invalid Date, https://www.britannica.com/science/Cambrian-Period. Accessed 26 April 2022.
R2.03b Ross, C. A. and Ross, J. R. P., Permian Period, Encyclopaedia Britannica. Available from: https://www.britannica.com/science/Permian-Period
R2.04 Wikipedia, Kiribati, Section: Climate data, Last updated 23 September, 2019. Available from: https://en.wikipedia.org/wiki/Kiribati
R2.05 Wikipedia, Tuvalu, Section: Climate data, Last updated 29 September, 2019. Available from: https://en.wikipedia.org/wiki/Tuvalu
R2.06 Wikipedia, Borneo, Last updated 23 September, 2019. Available from: https://en.wikipedia.org/wiki/Borneo
R2.07 Wikipedia, Pontianak, West Kalimantan, Section: Climate data, Last updated 23 September, 2019. Available from: https://en.wikipedia.org/wiki/Pontianak,_West_Kalimantan
R2.08 Scotese, C.R., Plate Tectonics, 540Ma - Modern World - Scotese Animation 022116b, Published on YouTube Feb 21, 2016. 2001, Computer Animations on CD-ROM, PALEOMAP Project, Arlington, Texas.
R2.09 Bagley, M., Devonian Period: Climate, Animals & Plants, 22 February, 2014, Live Science (Future US Inc). Available from: https://www.livescience.com/43596-devonian-period.html
and the 150MY Solar Cycle, W. Fiori, 28/4/2022
Wikipedia, Devonian, Last edited 6 May, 2019,
Available from: https://en.wikipedia.org/wiki/Devonian
R2.10 Marshall, M., The history of ice on earth, New Scientist Ltd., 24 May, 2010. Available from: https://www.newscientist.com/article/dn18949-the-history-of-ice-on-earth/
History.com Staff, Ice Age, 2015. Available from: https://www.history.com/topics/ice-age
R2.11 Fiori, W., 2021, Variability of the Total Solar Irradiance, published on academia.edu, https://www.academia.edu/45623010/variability_of_the_total_solar_irradiance
R2.12 M. Storey, R. A. Duncan and C. C. Swisher III, Paleocene-Eocene Thermal Maximum and the Opening of the Northeast Atlantic, Science Vol. 316, Issue 5824, pp. 587-589, DOI: 10.1126/science.1135274,
Available from: http://science.sciencemag.org/content/316/5824/587.full (2007).
R2.13 Wikipedia, Dinosaurs, Last edited on 30 January 2018. Available from: https://en.wikipedia.org/wiki/Dinosaur
R2.14 Wikipedia, Lists of Dinosaurs by Continent:
Africa – last changed on 31 December 2016
Available from: https://simple.wikipedia.org/wiki/List_of_African_dinosaurs
Asia – last changed on 5 April 2017
Available from: https://simple.wikipedia.org/wiki/List_of_Asian_dinosaurs
Australian and Antarctic - last edited on 13 January 2018
Available from: https://en.wikipedia.org/wiki/List_of_Australian_and_Antarctic_dinosaurs
Europe – last edited on 2 January 2018
Available from: https://en.wikipedia.org/wiki/List_of_European_dinosaurs
India and Madagascar - last edited on 2 June 2017
Available from: https://en.wikipedia.org/wiki/List_of_Indian_and_Madagascan_dinosaurs
North America – last edited on 30 January 2018
Available from: https://en.wikipedia.org/wiki/List_of_North_American_dinosaurs
South America – last edited on 7 February 2018
Available from: https://en.wikipedia.org/wiki/List_of_South_American_dinosaurs
R2.15 Cosgrove, J., Phanerozoic decline in origination rates, Fossils & Evolution “Diversity”, University of Iowa. Available from: http://faculty.chas.uni.edu/~groves/newPaleoDiversitytrendsandZFEL.pdf .
Method derived from graph, An apparent conundrum: Phanerozoic decline in origination rates. Excerpt by J. Cosgrove from publication: Principles of Palaeontology, by Foote, M. and Miller, A.
Used by permission of J. Cosgrove granted 13, June, 2018.
R2.16 Wikipedia, Eoraptor, Last updated 27 August, 2019. Available from: https://en.wikipedia.org/wiki/Eoraptor
R2.17 Monash University, Dinosaurs ‘did not hibernate’, 21 September, 2011. Science Alert article at https://www.sciencealert.com/shedding-light-on-australias-dinosaurs-of-darkness
AGT and the 150MY Solar Cycle, W. Fiori, 28/4/2022
Woodward HN, Rich TH, Chinsamy A, Vickers-Rich P (2011) Growth Dynamics of Australia's Polar Dinosaurs. PLOS ONE 6(8): e23339. https://doi.org/10.1371/journal.pone.0023339