Antarctica. It has an average temperature of -50 °C. There is enough ice locked up there to to increase the global sea levels by more than 70m. It has been that way for longer than mankind has existed. Antarctica has not always been such an inhospitable place though. In the time of the dinosaurs it was a temperature place. There were no glaciers, it was probably a pretty nice place to live.
When Antarctica started to freeze over 34 million years ago, the average temperature of the Earth was about 7 °C warmer than it is now. The freezing of Antarctica triggered one of the greatest climate change events ever recorded and the Earth has never been the same since that event. It also triggered the greatest extinction since the dinosaurs.
There is little question about certain facts. 34 million years ago the Antarctic Ice Age started up and it has not slowed down. Global sea levels dropped more than 50m. The ice age in Antarctica behaved the way they are supposed to behave. There were periods of advance and retreat that continued until 14 million years ago. It was then that the enormous ice caps began to form and they have existed ever since, although there are still periods of advance and retreat.
It is not the evolution of the continent itself that I wish to discuss, but the evolution of the theory of why Antarctica changed that I want to discuss. There is no place where the evidence is stronger that CO2 is impotent as a greenhouse gas than the story of Antarctica. This is why there is so much work to re-write the scientific history books about the story of Antarctica.
Back in 1977 a paper (Kennett, 1977) was published that concisely stated the facts about the history of Antarctica. Here is an excerpt from the abstract of his paper. I have added the bold sections.
….. During the Paleocene (t = ∼65 to 55 m.y. ago), Australia and Antarctica were joined. In the early Eocene (t = ∼55 m.y. ago), Australia began to drift northward from Antarctica, forming an ocean, although circum-Antarctic flow was blocked by the continental South Tasman Rise and Tasmania. During the Eocene (t = 55 to 38 m.y. ago) the Southern Ocean was relatively warm and the continent largely nonglaciated. Cool temperate vegetation existed in some regions. By the late Eocene (t = ∼39 m.y. ago) a shallow water connection had developed between the southern Indian and Pacific oceans over the South Tasman Rise. The first major climatic-glacial threshold was crossed 38 m.y. ago near the Eocene-Oligocene boundary, when substantial Antarctic sea ice began to form. This resulted in a rapid temperature drop in bottom waters of about 5°C and a major crisis in deep-sea faunas. Thermohaline oceanic circulation was initiated at this time much like that of the present day. …..
This climatic threshold was crossed as a result of the gradual isolation of Antarctica from Australia and perhaps the opening of the Drake Passage. During the Oligocene (t = 38 to 22 m.y. ago), widespread glaciation probably occurred throughout Antarctica, although no ice cap existed. By the middle to late Oligocene (t = ∼30 to 25 m.y. ago), deep-seated circum-Antarctic flow had developed south of the South Tasman Rise, as this had separated sufficiently from Victoria Land, Antarctica. Major reorganization resulted in southern hemisphere deep-sea sediment distribution patterns. The next principal climatic threshold was crossed during the middle Miocene (t = 14 to 11 m.y. ago) when the Antarctic ice cap formed. This occurred at about the time of closure of the Australian-Indonesian deep-sea passage. During the early Miocene, calcareous biogenic sediments began to be displaced northward by siliceous biogenic sediments with higher rates of sedimentation reflecting the beginning of circulation related to the development of the Antarctic Convergence. Since the middle Miocene the East Antarctic ice cap has remained a semipermanent feature exhibiting some changes in volume. The most important of these occurred during the latest Miocene (t = ∼5 m.y. ago) when ice volumes increased beyond those of the present day. This event was related to global climatic cooling, a rapid northward movement of about 300 km of the Antarctic Convergence…
This is a great scientific paper. It describes the cause of the changes that it is describing. The continents changed which caused the ocean currents to change and that changed the climate and caused Antarctica to become the frigid place that it is today. Tectonic changes caused the climate change.
The Antarctic Convergence describes the distance at which the Southern Ocean keeps the warm water away from Antarctica.
It is clear even today that the presence of land pushes the convergence zone closer to Antarctica. No factor is more significant to the average temperature of Antarctica and the convergence zone. This convergence zone is caused directly by the Antarctic Circumpolar Current (ACC). This current only exists because of the open ocean that surrounds Antarctica. Compare the current to the convergence zone.
It is obvious that the ACC defines the convergence zone. In order for Antarctica to have a different climate, the ACC would need to be stopped. Since that current has now existed for ~34 million years in a variety of different climates, it would seem like a reasonable assumption that it will continue to exist in the future.
Of course, it is unacceptable in today’s world for climate to be caused by geography or silly things like the ocean currents. Time for the warmists to fix the Antarctic problem.
Enter the General Circulation Model:
Since global warming became the scientific fad that it is today. A paper must be written to show that CO2 is the main reason that any climate event in history happened. The problem is that in this case, they really prove that GCM’s are incapable of modelling the Earth’s climate. The best paper (DeConto, 2003) to show just how far they will go to make CO2 the main culprit.
Here is the abstract in its entirety. Bold added by myself.
The sudden, widespread glaciation of Antarctica and the associated shift towards colder temperatures at the Eocene/Oligocene boundary (34 million years ago) (refs 1–4) is one of the most fundamental reorganizations of global climate known in the geologic record. The glaciation of Antarctica has hitherto been thought to result from the tectonic opening of Southern Ocean gateways, which enabled the formation of the Antarctic Circumpolar Current and the subsequent thermal isolation of the Antarctic continent5. Here we simulate the glacial inception and early growth of the East Antarctic Ice Sheet using a general circulation model with coupled components for atmosphere, ocean, ice sheet and sediment, and which incorporates palaeogeography, greenhouse gas, changing orbital parameters, and varying ocean heat transport. In our model, declining Cenozoic CO2 first leads to the formation of small, highly dynamic ice caps on high Antarctic plateaux. At a later time, a CO2 threshold is crossed, initiating ice-sheet height/mass-balance feedbacks that cause the ice caps to expand rapidly with large orbital variations, eventually coalescing into a continental-scale East Antarctic Ice Sheet. According to our simulation the opening of Southern Ocean gateways plays a secondary role in this transition, relative to CO2 concentration.
This is the opposite of the initial paper. They provide no cause for anything, other than the circular logic of their conclusion. Decreasing CO2 caused more decreasing CO2 until a critical low level caused Antarctica to go cold. They did all of that based on a GCM. This is a perfect example of failing to perform any science at all, only to run a model to give the desired results.
This result is impossible though. If such a drop in CO2 level caused the cooling in Antarctica, then why did the Northern Hemisphere not start its Ice Age for another 31 million years? How could CO2 induced cooling be selective to a single polar region? That is a fascinating question and one that I am sure a GCM could answer if given enough fiddling, but the result will be meaningless.
Antarctica is truly the perfect battle line against GCM’s. There is no significant doubt that the formation of the ACC is the cause of both the cooling and the drop in CO2 that happened as a result of the cooling oceans. In the global warming debate, they have jumped the shark. They have no basis for their argument in Antarctica, but they have tried it anyway. If you ever had a doubt about the ability of GCM’s before, this is the best evidence that the results are subject to the whim of the person running them.