4 ms·
Is it true that only 30,000 years ago the level of the sea was very different? lower in that case, exposing the land bridge at Alaska, and connecting the Islan
by mistrial9 4y ago
Is it true that only 30,000 years ago the level of the sea was very different? lower in that case, exposing the land bridge at Alaska, and connecting the Islands north of Australia.. and previous to that, the sea level was much higher? evidence is the inland sea that is California Central Valley..
- nigerian1981 4y agoI don’t see how given the Earth is only 6000 years old.
- GekkePrutser 4y agoAnd flat, so any excess water will just run over the edge.
- SketchySeaBeast 4y agoGood thing turtles are OK getting wet.
- munk-a 4y agoIf they can put up with elephants standing on their backs then a bit a water is clearly not going to bother them.
- thro388 4y agoYes, there is periodic cycle, depending on ice ages.
- wcoenen 4y agoThe past 5000 years have been quite stable, but there have been dramatic changes from melting ice caps before that. See https://commons.m.wikimedia.org/wiki/File:Post-Glacial_Sea_Level.png https://commons.m.wikimedia.org/wiki/File:Post-Glacial_Sea_L... With a high enough warming rate, we might get a chance to see what a "meltwater pulse" looks like :-/
- AlotOfReading 4y agoModern sea level is the highest it's been in over 100k years. Central valley hasn't been anything close to an inland sea for about 1.5m years, but that has more to do with deposited sediment than sea level.
- colechristensen 4y agoYes, there has been a cycle going on in the most recent era of flipping between glaciers growing and shrinking. I don't recall the actual date but the most recent maximum glacier coverage was on the order of 30,000 years ago. The whole of human civilization we know about more or less happened since the last retreat of the glaciers. There have also been times when the polar caps melted completely and there were rainforests pole to pole.
- lizknope 4y agoIf you go back tens of millions of years ago there were dinosaurs in polar regions. Of course it was much warmer then https://www.smithsonianmag.com/history/the-strange-lives-of-polar-dinosaurs-180347471/ https://www.smithsonianmag.com/history/the-strange-lives-of-... https://en.wikipedia.org/wiki/South_Polar_region_of_the_Cretaceous https://en.wikipedia.org/wiki/South_Polar_region_of_the_Cret...
- cwmma 4y agoThe dinosaurs in the polar reason isn't because it was warmer, it's because the Strait of Magellan were closed. One of the reasons we are in an ice age right now (which refers to a period where you have periodicly advancing and retreating glaciers) is because you have a continent on the pole and a clear sea lane around it, before the Strait of Magellan opened you have a current that circulated between the poles and equater evening out the temperatures allowing for ice free poles.
- monort 4y agoThe same three atmospheric cells exist in the northern hemisphere and there is no continent there. Why is that? https://en.wikipedia.org/wiki/Atmospheric_circulation https://en.wikipedia.org/wiki/Atmospheric_circulation
- cwmma 4y agoThose are different, this is about water circulation not air circulation, water has a much higher specific heat so it it's far more important when it comes to temperature circulation.