Comments by "Michael Deierhoi" (@michaeldeierhoi4096) on "The Last Time the Globe Warmed" video.

  1.  @bobleclair5665  Or not. Bevause climate scientists report that the while the thremohaline current could stop and lead to cooler temperatures in Western Europe an ice age is very unlikely because the GHG concentration is so high and increasing. GHG's were much lower in the ice ages anyway and it would take both a shift in Milankovitch Cycles AND lower GHG's to trigger an ice age. Milankovitch cycles are not not due to correlate for at least 10,000 years. Who knows where the GHG's will be by then!?
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  2. @busty. As a climate warmed at the end of an ice age that is true. Milankovitch Cycles are the trigger for starting and stopping glacial periods. When the Milankovitch cycles switch to allowing more sunlight to reach the earth the atmosphere begins to warm which in turn causes the oceans to warm. As the oceans warm over hundreds of years CO2 is released back into the atmosphere which AMPLIFIES the warming into the Interglacial period. But when the climate is warming like it is now and there is a high concentration of CO2 in the atmosphere most CO2 goes INTO the ocean. And that has to the with physics of the partial pressure of CO2 being higher in the atmosphere then the ocean. Most CO2 entering the oceans converts to carbonic acid, carbonate or bicarbonate.
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  3. It is true the Polar Ice Caps have been gone for probably most of earth's history and have only become more present in the last 34 million years since the beginning of the Oligocene Epoch. This video focuses particularly on the PETM when there was no polar ice caps. And during the interglacial periods of the Pleistocene the ice caps did not retreat completely. At that time the Drake Passage between South America and Antarctica opened up allowing the Antarctica Circumpolar Current to flow unobstructed which turned the South pole into the ice cap it is today. The Arctic Ice Cap formed later also due to geographic configurations closer to todays. The Arctic Ice Cap is declining today because of accelerated warming in the Arctic due to the GHG concentration being almost 50% higher then it was throughout the previous 10,000 years! Prior to that time it was as low as 190 ppm during glaciation.
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  4. @Bob Le Clair. That's because those two phenomena did not contribute much of anything to warming during the PETM. In the case of solar radiance the sun is remarkably stable over time and any fluctuations are far out weighted by GHG concentrations in the atmosphere anyway. We are seeing that now as the climate has warmed most significantly since 1975 yet the sun has also been less active with minimal sun spot activity. And the Malankovitch Cycles played no significant role until certain continents were in more current geographic positions. As far as warming again it was the elevated GHG in the atmosphere that exceeded any other phenomena either terrestrial or astronomical that could have warmed the earth. And as far as cooling FYI for example the Antarctic ice cap did not even develop until after 34 million years ago when the Drake Passage opened up. The Drake Passage is the water way between the Antarctic Penninsula and South America's Tierra del Fuego. This allowed for the Antarctic Circumpolar Current to begin circulating which confined the cold to the South Pole preventing the previous warm air currents from the north which had keep it temperate.
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  5.  @bobleclair5665  What things are left out that you think should be included?
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  6.  @awd3264  Many and perhaps most climate scientists had their foundation in geology which necessitates an extensive background in physics. A specialty in geology is geochemistry which includes terrestrial study of the of the earth. Other specialties in geology include glacialogy and atmospheric chemistry. There are also oceanographers whose study also focused on climate science. Peter Wadhams, who has several videos on youtube studied oceanography, but specialized in the Arctic. All of these fields and more can and do focus on climate science and have for decades. And each field has become more refined and technologically sophisticated over time.
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  7. @Robby. Except that is not what is going on now. CO2 was released from the oceans at the end of the glacial cycle because the Milankovich Cycles changed to allow more sun light to reach the earth. As the earth land and atmosphere warmed so too did the oceans which caused the release of CO2 back into the atmosphere. But now the CO2 in the atmosphere has a higher partial pressure because of the higher concentration. 410 ppm now vs 280 ppm before the industrial era began. That higher partial pressure of CO2 continues to add CO2 to the ocean and most CO2 in the ocean is converted to carbonic acid which makes the oceans more acidic and bicarbonate and carbonates used by molluscs. And humans are also adding CO2 much faster then even happened during the PETM when it took 20,000 years given much life time to adapt or evolve.
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