The Grand View: 4 Billion Years Of Climate Change


According to Meg Urry, the head of the physics department at Yale University: “Scientists observe nature, then develop theories that describe their observations. Science is driven by nature itself, and nature gives us no choice. It is what it is.” While some of the dates presented here may change and scientists continue to argue some of the fine points, here is what science thinks it knows about life, the Universe and everything.

Around 13.7 billion years ago the Universe came into existence. Not long afterward the Milky Way galaxy was formed. Stars formed, transmuted elements in nuclear fire and ended their lives in supernovae explosions. This cycle was repeated many times for many different stars.

Then, 4.6 billion years ago our Sun was born out of the ashes of older dead stars. Along with the Sun a large brood of planets was also formed, including the one we call Earth. A million years after the birth of our sun, the violent explosion of a nearby supernova nearly ended life on Earth before it began. Over the next four and a half billion years, forces of nature shaped our planet and the life it harbored.

Buffeted by supernovae, barely surviving the traumatic birth of the Moon, bombarded by asteroids, the resilient Earth endured. And despite planet-freezing ice ages, devastating mass extinctions and ever changing climate life not only survived, it thrived. Even though meteors continued to rain down on the young planet there is evidence that as long as 4.2 billion years ago liquid water, the prerequisite for life as we know it, was present. The evidence also indicates that life has been present on our planet for close to 4 billion years, though for most of that time it was relatively simple single celled life. At the start, Earth's atmosphere was a toxic mix of methane, carbon dioxide and ammonia—oxygen was nearly absent in the atmosphere of early Earth. To humans and most of the world's familiar flora and fauna, this atmosphere would have been toxic.

Asteroid impacts, tremendous volcanic eruptions, and shifting tectonic plates resulted in drastic changes in climate and the emergence of new life forms. Somewhere along the way the simple microorganisms, which were ancient Earth's only inhabitants, developed photosynthesis that created a net gain of oxygen first in the ocean and later in the atmosphere. Then, 2.3 billion years ago, the world's first ecological disaster occurred when free oxygen established a permanent presence in the atmosphere. Known as the Great Oxidation or the Oxygen Catastrophe, almost every living thing on Earth died as a result of this massive bacteria-induced climate change.

Scientists know this from the minerals present in the rock record. Between 2.5-2.3 billion years ago, during the early Proterozoic Eon, extensive deposits of pyrite (iron sulfide) and uranite (Uranium oxide) can be found in river sediments. These minerals require low oxygen levels to form. From 2.3 billion years onward iron rust can be found, an indication of the presence of free oxygen. Even so, the oxygen levels were but a fraction of today's and intense radiation from the Sun sleeted down on the plant. Eventually, oxygen would solve the radiation problem as well as molecules of ozone (O3) were created in the stratosphere forming the protective ozone layer.

This first example of life radically changing Earth's environment, some times to the detriment of older life forms, was a good thing for our species for without the change in atmospheric composition we would never have existed at all. According to Thorne Lay, Professor of Earth Sciences at UC Santa Cruz : “Life itself modified the Earth system. As the system changed, more complex life forms became viable. Eventually diverse multi-cellular organisms flourished. But not without first being smacked in the face by a few snowballs.” And what snowballs they were!

Eight hundred million years ago, during the Neoproterozoic Era, Earth underwent a monstrous ice age. There is evidence of glacial ice in tropical latitudes, only 15° to 30° north of the equator. In our world, this would mean glaciers as far south as Miami, Florida. Earth would have looked like a different planet, with almost no open ocean and few areas of exposed rock. Only ice and snow, a world of almost pure white.

An artist's conception of what a snowball Earth would look like today.

At that time, most of the land belonged to the super-continent of Rodinia, which formed around 1,100 mya. Rodinia contained the lands that makes up the modern continents today, but not in a configuration we would recognize. North America was in the middle. South America, Australia and Antarctica were packed around North America. Rodinia straddled the tropics, leaving a single vast ocean sweeping across the other side of the globe. There was no land at either pole.

In 1992, Joseph L. Kirschvink, of the California Institute of Technology in Pasadena, put forward a theory that our planet had almost completely frozen from pole to pole, with the only open ocean choked with pack ice. He named this condition “Snowball Earth.” Other researchers have calculated that some of the glacial periods during this time had lasted as long as 10 million years. During these periods the ocean may have frozen over completely, blocking all sunlight and killing most ocean life.

In fact, scientists now think that there have been ice ages dating back all the way to the middle of the Archean Eon, around 2.8 billion years ago. We have evidence of this from layers of sediment found in rock formations known to belong to that period. On occasion, these episodes lasted several hundred million years, and may have rivaled the ice age during the Neoproterozoic in intensity. There may have been several Snowball Earth periods in our planet's past.

The next major milestone for life on Earth occurred at the beginning of the Phanerozoic Eon, 542 million years ago, with the Cambrian Explosion. This event, with new multicellular organisms popping up in great profusion, resulted in an explosion of life. It marked the end of the Proterozoic Eon and the beginning of the Phanerozoic, Greek for “visible life.” This eon signals the rise of truly complex life, where individual organisms are large enough to be recognized without a microscope.

Different geologic time periods are marked by significant changes in the types of creatures living on Earth. The rock deposited during the Phanerozoic Eon contains evidence of fossilized hard body parts from living things and it is this fossil record that is used to date rock layers from the three eras. By reading the fossil record, scientists have constructed an outline of the development of life during the time following the Cambrian Explosion. Note that it is the changing cast of fossils that allows science to map the past—the history of our planet was written in rock by the fossil remains of uncounted extinct species.

So we see that there were mass extinctions, changes to atmospheric gas proportions and even multiple ice ages prior to the beginning of the Phanerozoic. However, the argument can be made that conditions during the Precambrian (the time prior to 542 million years ago) were not really representative of Earth's climate since complex life spread across the planet. So let's take a look at the “recent” past of the Phanerozoic.

Welcome to the Phanerozoic

To closely examine each era and period of the Phanerozoic would take a lot more space than I wish to commit to a single blog post so we will concentrate on the variation in several key environmental factors over that entire time span. These factors are temperature, carbon dioxide levels, ice age conditions, and species extinction and its impact on diversity. But before reviewing these data I do want to mention one period from the late Paleozoic Era that will give a flavor of the types of variation seen in the past.

In the late Paleozoic Era, during the Carboniferous Period, great forests of primitive plants thrived on land, forming extensive peat-swamps. These huge masses of plant matter were buried with sediment, eventually forming the great coal deposits found in North America, Europe and around the world. A global drop in sea level at the end of the Devonian reversed early in the Carboniferous, creating large shallow seas and huge deposits of carbonate minerals. These deposits trapped large quantities of atmospheric carbon that would later form vast beds of limestone.

During the later part of the Carboniferous, the amount of oxygen in Earth's atmosphere was about 35%, much higher than it is today. According to Robert Berner, levels atmospheric oxygen levels have varied between 15% and 30% over the past 550 million years (see “Atmospheric oxygen over Phanerozoic time” in PNAS September 28, 1999). At the same time, global CO2 went below 300 parts per million—a level which is now associated with glacial periods. The abundance of O2 led to the existence of the largest insects ever seen on Earth. Hawk-sized dragonflies, with 29 inch (75 cm) wing spans, spiders the size of house plants, 5 foot (1.5 m) long centipedes and soup bowl-sized crawling bugs. It was truly a time when insects ruled the planet. Perhaps it's a good thing the atmospheric oxygen level is only 21% today.

Carboniferous plants resembled the plants that live in tropical and mildly temperate areas today. From fossils, we know that many of them lacked growth rings, suggesting a uniform climate. But the climate was changing. By the middle of the Carboniferous, Earth was sliding into an Ice Age, the Permo-Carboniferous or Karoo Ice Age. The growth of large ice sheets at the southern pole locked up large amounts of water as ice. Because so much water was taken out of the environment, sea levels dropped, leading to a mass extinction of shallow marine invertebrates, the gradual decline of the swamps, and an increase in dry land.

Many times, these conditions were reversed when the glaciers receded. Glacial melt water was released back into the oceans, and again flooded the swamps and low-lying plains. Carboniferous rock formations often occur as a pattern of stripes, with alternating shale and coal seams indicating the cyclic flooding and drying of the land. Even under these stressful conditions, or perhaps because of them, life continued to develop. By the end of the era, the first large reptiles and the first modern plants, ancestors of today's conifers, had appeared.

In many ways the Carboniferous is unique in terms of its combination of atmosphere, climate and life forms, but each period of geologic time is unique—that's why they are distinguished with individual names by the ICS. Fact is, the thing that makes these remote periods in time similar is that they are all different from one another—the only constant factor running through the sweep of Earth history is change. For greater detail on the characteristics of these geologic periods see The Resilient Earth chapter 4, “Unprecedented Climate Change?,” or get a copy of our book from Amazon.

Now that we have a flavor of the types of change Earth has experienced in the past let's examine the temperature variation over the Phanerozoic Era. Below is a figure that shows science's best guess at how temperature has varied over the past 542 million years. Notice the wide variation in temperature over time, sometimes colder than the average 14°C of today but much of the time considerably warmer. Note also the blue rectangles along the bottom of the plot representing periods of ice house conditions. Even though there have been several extensive ice ages during the Phanerozoic, for the majority of the past half billion years there have been no permanent ice caps in either hemisphere. In that sense, the total melting of the Greenland and Antarctic glacial ice sheets would mark a return to historically normal conditions for our planet.

Next, take a look at variation in atmospheric CO2 levels shown in the graph below. Though the uncertainty in the measurments grows as we look farther into the past the general trend can be seen—there used to be much more CO2 in the air in most earlier times. There is an overall trend toward reduced levels but what is most interesting is to compare the CO2 graph with the temperature graph above.

At this scale, there is really no apparent correlation between carbon dioxide levels and global temperatures. What's more, there have been ice ages when CO2 has been as much as 10 to 15 times higher than modern levels (for example the end-Ordovician Ice Age). There have also been times when temperature was increasing but CO2 was decreasing and times when CO2 was increasing but temperatures decreasing (during the Silurian and Devonian and during the Triassic and Jurassic, respectively).

The dip in CO2 levels at the end of the Carboniferous and into the Permian can be attributed to the over active coal swamps that were busy accumulating the thick coal seams that provide energy for much of the world's power generation today. That dip persisted throughout the great Karoo Ice Age (360-260 mya) but started to rise following the Permian-Triassic Extinction (251 mya). Many have speculated that ice ages are a cause of ancient mass extinction events and there may be a connection. The timing of know extinction events is shown in the biodiversity graph below.

The Ordovician-Silurian extinction event, also called the end-Ordovician extinction, was the third-largest of the five major extinction events in Earth's history in terms of percentage of genera that went extinct and second largest overall in the overall loss of life. Somewhere between 450 and 440 mya, two bursts of extinction occurred, separated by about a million years. Notice how, after each major extinction (denoted by the red triangles) life bounces back with increased diversity. Clearly life rises to a challenge (for more about extinction see “Nature, Cruel and Uncaring”).

The graph below shows CO2, temperature and ice age timing information on a single plot. Did the cold have something to do with the extinction? Arguments rage on in the paleological community. Conversely, some have suggested that a sudden rise in CO2 levels at the end of the Permian was responsible for the Permian-Triassic Extinction. Science may never know.

What we do know is human CO2 emissions at their worst cannot approach the levels of natural GHG release, even events that did not trigger mass extinctions (see “Could Human CO2 Emissions Cause Another PETM?”). But what about the often mentioned link between CO2 and temperature? “In a nutshell, theoretical models cannot explain what we observe in the geological record,” says Rice University Oceanographer Gerald Dickens, “There appears to be something fundamentally wrong with the way temperature and carbon are linked in climate models.”

There have been many other factors at work during the past that affect climate change. This examination—being limited to carbon dioxide levels, temperature and the occurrence of ice ages—ignores the impact of shifting continents, variation in solar activity, orbital cycles and the possible impact of cosmic rays on Earth's climate. Greater detail on all of these factors are presented in our book. One interesting thing to notice is that having a continental land mass spanning either pole seems to help promote ice house climate conditions. During the Devonian the supercontinent Gondwana passed over the south pole, during the Carboniferous the polar ice cap covered the southern end of Pangaea, and today we have Antarctica astride the south polar region.


That concludes our whirlwind tour of Earth's climate history. There are a number of observations that can be made from our overview of the Phanerozoic:

  • Earth’s temperature is always changing.
  • Over time there have been periods when it has been colder than it is today.
  • For most of the Phanerozoic it has been much warmer than it is today.
  • Life has persisted during periods both hot and cold.
  • There is no one “right” temperature.
  • Carbon dioxide has always been present in Earth’s atmosphere.
  • Over time there have been periods when CO2 has increased and decreased naturally.
  • For most of the Phanerozoic it has been much higher than it is today.
  • Life has persisted during periods with high CO2 and low CO2.
  • CO2 levels will change with or without human contributions.
  • Over time there have been a number of ice ages—Life has endured multiple ice ages.
  • For most of the Phanerozoic there have been no persistent polar ice caps.

What the future holds climate scientists are unable to portend with all their computer models and IPCC consensus reports. The Earth and its climate are constantly changing—there is no one correct climate or temperature for our planet. Those who say CO2 is the most important factor in climate change, that human GHG emissions will cause runaway global warming, have no historical basis for such claims.

As Earth's climate history has shown, nothing predicted by the global warming alarmists would be unprecedented—Earth's climate has been colder than today's and much, much warmer. CO2 levels have also been many times higher than they currently are, even during ice ages. Ice ages come and go, caused by mechanisms mankind is powerless to control. And after every ice age the world warms and the glaciers disappear only to return millions of years later. No change in climate is irreversible. Given 4 billion years of Earth history and 542 million years of complex life, blaming mankind for 9,000 years of global warming seems rather silly. As it says in Ecclesiastes: “What has been is what will be, and what has been done is what will be done; there is nothing new under the sun.”

Be safe, enjoy the interglacial and stay skeptical.

[ The information in this post was taken from our book The Resilient Earth and represents the first half of my presentation to the Scientists for Truth conference held during August 2009, in Springfield, Mo. After hearing my presentation Dennis Avery, co-author of Unstoppable Global Warming: Every 1500 Years, christened it the “Grand View” of climate change, hence the title of this post. For more information and references see chapters 4, 5, and 6 of TRE. ]

A question about the CO2 graph

I recently received a question from Peter, one of our readers, regarding the Phanerozoic CO2 graph. Here is Peter's question:

I notice that the graphs used showing the last half billion years of temp and CO2 are quite different from the commonly available graph attributed to C R Sootese and R.A.Berner 2001. One presumes that these graphs are a collation of data from possibly hundreds of research papers so one would also expect a relatively high degree of similarity. I would be grateful if you could comment on this as it does not help present a front against stupidity when key information is not consistent.
Keep up the good work.

The figure in my article, and in our book, is basically the same as the one created by Robert A. Rohde from published data and is incorporated into the Global Warming Art project. The major difference is that I reversed the direction of the time axis because I feel that most people are more comfortable with time increasing from left to right. To quote from Wikipedia about the sources of data in the graph:

This figures shows estimates of the changes in carbon dioxide concentrations during the Phanerozoic. Three estimates are based on geochemical modeling: GEOCARB III (Berner and Kothavala 2001), COPSE (Bergmann et al. 2004) and Rothman (2001). These are compared to the carbon dioxide measurement database of Royer et al. (2004) and a 30 Myr filtered average of those data. Error envelopes are shown when they were available. The right hand scale shows the ratio of these measurements to the estimated average for the last several million years (the Quaternary). Customary labels for the periods of geologic time appear at the bottom.

Direct determination of past carbon dioxide levels relies primarily on the interpretation of carbon isotopic ratios in fossilized soils (paleosols) or the shells of phytoplankton and through interpretation of stomatal density in fossil plants. Each of these is subject to substantial systematic uncertainty.

Estimates of carbon dioxide changes through geochemical modeling instead rely on quantifying the geological sources and sinks for carbon dioxide over long time scales particularly: volcanic inputs, erosion and carbonate deposition. As such, these models are largely independent of direct measurements of carbon dioxide.

While we don't make a habit of using Wikipedia as a source of information, in this case the description is accurate and the figure did not originate with them. The data presented is widely accepted, as shown in the graph below, taken from MIT's online OpenCourseWare Geobiology course. Note that this graph also has the same time axis orientation as our graph.

Similarly, the temperature graph was derived from an original prepared from publicly available data that is part of the Global Warming Art project. Again, I have reversed the time axis to increase from left to right. All data have been adjusted to 2004 ICS geologic timescale.

Temperatures are estimated from the long-term evolution of oxygen isotope ratios as measured in fossils, reported by Veizer et al. (1999), and updated online in 2004. Such ratios reflect both the local temperature at the site of deposition and global changes associated with the extent of permanent continental glaciation. As such, relative changes in oxygen isotope ratios can be interpreted as rough changes in climate. Quantitative conversion between these data and direct temperature changes is a complicated process subject to many systematic uncertainties, however it is estimated that each 1 part per thousand change in δ18O represents roughly a 1.5-2 °C change in tropical sea surface temperatures (Veizer et al. 2000).

Also shown on this figure are blue bars showing periods when geological criteria (Frakes et al. 1992) indicate cold temperatures and glaciation as reported by Veizer et al. (2000). The Jurassic-Cretaceous period, plotted as a lighter blue bar, was interpreted as a “cool” period on geological grounds, but the configuration of continents at that time was not conducive to the formation of large glacial ice sheets.

The short-term average was constructed by applying a σ = 3 Myr Gaussian weighted moving average to the original 16,692 reported measurements. The gray bar is the associated 95% statistical uncertainty in the moving average. The long-term average is a σ = 15 Myr Gaussian average of the short-term record.

Translation into Spanish: "The Grand View..."

Dear Sir

For the last years, I've been trying to explain my view about the truth on climate change to Spanish talking people, specially because there are few articles on the issue in our language.

Like the other themes that I post on general scientific divulgation, it has been (an still is) a private non effort effort.

May I translate this article into Spanish and publish it in my blog:
with due recognition and link to the original, of course?

Yours truly
Heber Rizzo

Permission to translate


Please feel free to translate "The Grand View" or any of my other blog postings into Spanish. All I ask is proper attribution and a link back to this site be included. My columns have been translated into German, Dutch and Portuguese on occasion and I welcome the chance to reach a wider, non-English speaking audience.


Translated and

Well, I feel honored. You

Well, I feel honored.
You will get the link to the translation as soon as I publish it.
Thank you very much.

Existence of Eath

Amazing information.. I loved the observation part.. It is the valuable information to those who think earth will be no more in 2012. Nice buddy..!

Angeline @ marcus evans scam

The Short Story


Good stuff mate. Its positively amazing the belief structures of Homo sapiens leans so strongly towards predictions rather than facts. I may have mentioned before that a large psychological study done in the 1970's proved that humans are 9 times more susceptible to rumor than they are to facts. Probably explains a lot of everything that goes on.

Here I send my latest rendition of what I call "The Short Story", where I have attempted to focus mostly on the period from the Eemian to the Holocene, with flavors from older times added for spice.


In some ways, I applaud the sense of urgency that accompanies the perceived need to do something to affect climate change. The need is there in more ways than you presently know. But the means could be another matter entirely. The Akkadian Empire under Sargon (2,300-2,200 BC), mankind’s first empire ever, succumbed to climate change that happened rather suddenly. A 300 year long period of drought struck this nascent civilization and toppled what turned out to be only a 100 year empire. The Old Kingdom of Egypt and the Harappans of the Indus Valley suffered a similar fate 4,200 years ago, succumbing to an abrupt drought that ended those civilizations, with Egyptians “forced to commit unheard of atrocities such as eating their own children and violating the sacred sanctity of their own dead (Fekri Hassan, 2001)”. The Mayans had pretty much the same luck with three periods of extreme drought at 810, 860 and 910 AD. Sadly just two years after the last drought, which saw 95% of the Mayan population gone, wet years returned to the Yucatan.

A reconstruction from fossil algae in sediments from Drought Lake in North Dakota of the past 2000 years found that dry conditions were far and away the rule in the High Plains, with the Dust Bowl conditions of the 1930’s one of the lesser dry spikes found in the record. Half of the warming that brought us out of the last ice age (the Wisconsin) occurred in less than a decade.

There were 24 Dansgaard-Oeschger oscillations between this interglacial, the Holocene, the interglacial in which all of human civilization has occurred, and the last one, the Eemian, in which the first fossils of Homo sapiens are to be found. D-O oscillations average 1,500 years, and have the same characteristic sawtooth temperature shape that the major ice-age/interglacials do, a sudden, dramatic, reliable, and seemingly unavoidable rise of between 8-10C on average, taking from only a few years to mere decades, then a shaky period of warmth (less than interglacial warmth), followed by a steep descent back into ice age conditions. Each D-O oscillation is slightly colder than the previous one through about seven oscillations; then there is an especially long, cold interval, followed by an especially large, abrupt warming up to 16C (a Bond cycle). During the latter parts of the especially cold intervals, armadas of icebergs are rafted across the North Atlantic (Heinrich events), their passage recorded reliably by the deep ocean sediment cores which capture the telltale signature of these events in dropstones and detritus melted out of them.

We know with absolute certainty that these events happen, with evidence of D-O oscillations extending back some 680 million years. We do not know, yet, precisely what causes them. What we do know is that the past 6 interglacials (dating back to the Mid Pleistocene Transition) have lasted roughly half of a precessional cycle, or currently 11,500 years, which just happens to be the present age of the Holocene. What we know is that N65 latitude insolation values are very close now to what they were at the close of the Eemian. What we also know is that GHGs, like us, seem to have played only a spectator role to all of these alarming natural transitions, with temperature changes leading GHG concentrations by a considerable margin of time (800-1,300 years). What we do not know is if the reverse could occur, anthropogenic sourced GHGs triggering a climate change event, for perhaps the first time ever. What we do know is that earth’s climate is bimodal, cold 90% and warm 10% of the time for the past million years or so, with the transition times (such as at the end of an interglacial) well known from proxy records to be quite sensitive to forcings we do not yet understand, and the forcings we have identified seemingly incapable of producing the responses we see in the paleoclimate record. Including the recent paleoclimate record.

The climb out from the Last Glacial Maximum of the Wisconsin ice age (called Termination 1 with sea level bottoming out about 121 meters, ~397 feet, below present) into the Holocene is studded with the Younger Dryas, a 1,300 year near instantaneous return to ice age conditions. “Briefly, the data indicate that cooling into the Younger Dryas occurred in a few prominent decade(s)-long steps, whereas warming at the end of it occurred primarily in one especially large step of about 8°C in about 10 years and was accompanied by a doubling of snow accumulation in 3 years; most of the accumulation-rate change occurred in 1 year (National Research Council, 2002)”. Far more suddenly we came out of it: “Taylor et al. (1997) found that most of the change in most indicators occurred in one step over about 5 years at the end of the Younger Dryas, although additional steps of similar length but much smaller magnitude preceded and followed the main step, spanning a total of about 50 years (NRC, 2002)”.

Termination 1 went into top-fuel, carbon-free overdrive with what is referred to as melt water pulse 1a (mwp-1a) centered at about 14,680 years ago which resulted in a 24 meter rise (about 78 feet) in sea level believed to have occurred at the rate of 4.5 cm (about 2 inches) a year. It was followed around 12,260 years ago by mwp-1b with a 28 meter (about 92 feet) rise nearer 5 cm per year. Recent model results predict that sea level is currently rising at 32cm/100 years. If we take the low-end of the natural “noise” clocked at 4.5 cm/yr (or 450cm/century) we, (meaning us) will have to kick in some serious turbos (carbos?) to net one and a half orders of magnitude boost if we hope to trump mother nature’s bottom bracket, but most recent finest “heat”.

Another variable worth devoting some cpu time to is just how astonishingly well the fourth cycle of eccentricity matches up with hominid evolution.

“An examination of the fossil record indicates that the key junctures in hominin evolution reported nowadays at 2.6, 1.8 and 1 Ma coincide with 400 kyr eccentricity maxima, which suggests that periods with enhanced speciation and extinction events coincided with periods of maximum climate variability on high moisture levels.”

state Trauth, et al (2009) in Quaternary Science Reviews. There is just nothing quite like having such a natural fly land in your climate change soup. As it turns out, periods of wet maximum climate variability (in modern lingo, global warming/global cooling correctly re-branded as climate change), cook-up the larger braincases. We went from 500-550cc braincases 2.8 mya to the average of about 2,500cc today in the most rapid encephalization of any mammal in the fossil record.

Between 6,000 and 7,000 years ago, a period known to geologists and paleoclimatologists as the Holocene Climate Optimum, sea levels peaked between 1.5 to a maximum-found 8 meters higher than today (average in the literature seems to be about 2.5-3.5 meters), and during the Eemian Optimum, some 20 meters (about 60 feet) higher than today. We may have trumped that during marine isotope stage 11 (MIS 11), when it may have reached 21.3 meters (about 70 feet) above msl. During the seven post MPT ice ages, sea levels dropped some 100 or more meters below present, the water tied up in the miles-thick ice sheets that have spread in North America as far south as Kansas. These are just some of the facts of the abrupt climate changes which we, as Homo sapiens, have experienced.

General Circulation Models, of which the IPCC references 20+, have yet to reproduce a single known abrupt paleoclimate change fed with the proxy data. The latest GCM models produce predictions based on a variety of input data and complex equations which few of us would understand. But for all the complexity and investment, they are still only predictions.

Belief in, and acting as a result of, such predictions has opened up what may be the first chapter in faith-based science (W. should be so proud). The astonishing enormity of natural climate change provides a harrowing appreciation of massive sea level “noise” that can range to over 400 feet (with a beat of lesser, rank-and-file swings [think D-O oscillations]) and temperature shifts that lord over all future fantasies you have yet heard. Normally, this would give pause to a rational being, so faced with populous facts and patent variables.

What might be quite ironic is that if GHG predicted global warming is in fact real, and, at half of a precessional cycle, we are near to the cliff of the next natural shift to an ice age, we may find ourselves needing to generate as much GHGs as possible to ease our transition into the next ice age. So as I said at the beginning, doing something about climate change is not necessarily a bad thing. Doing the right thing might prove to be quite another. The ice ages and associated interglacials are well known to be paced by the eccentricity, obliquity and precession cycles in earth’s rickety orbit. These we will do nothing about. D-O oscillations show strong evidence of being tied to the 1,500 year cycle of solar output, something we cannot change.

So be ever thoughtful of both facts and predictions before leaping to a conclusion. It was in fact a LEAP that terminated the last interglacial, the cold Late Eemian Aridity Pulse which lasted 468 years and ended with a precipitous drop into the Wisconsin ice age. And yes, we were indeed there. We had been on the stage as our stone-age selves about the same length of time during that interglacial that our civilizations have been during this one.

William McClenney

Your Short Story is a Good Story

Yes William,
Thanks for the excellent material which proves our point exactly. When Doug and I wrote the The Resilient Earth, we wanted to drive home that nature is what it is. You have aptly demonstrated this.

Kind regards to you.