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Global Warming 5 Million Years Ago In Antarctic Drastically Raised Sea Levels
An anonymous reader writes "As temperatures rise, scientists continue to worry about the effects of melting Antarctic ice, which threatens to raise sea levels and swamp coastal communities. This event, though, isn't unprecedented. Researchers have uncovered evidence that reveals global warming five million years ago may have caused parts of Antarctica's ice sheets to melt, causing sea levels to rise by about 20 meters."
The interglacial periods coincide with variations in the earths orbit.
eccentricity, tilt and precession all interacting. So yes it is pretty well understood why glaciation occurs. Yes it has been taken into account. No it does no account for the current changes being seen.
According to IPCC's WORST-CASE estimates (from which they have recently backed off), sea levels were not projected to rise by more than about a meter over the next 100 years.
I daresay we can adapt fast enough to that.
what a jerk
A couple of important points: Firstly, 5 million years ago, there weren't 7 billion people living on Earth, people whose food supply was dependent on an agricultural system tightly adapted to today's particular climatic conditons. I will always remember a lecture given by one of my geology professors. He drew a graph on the board, initially without a scale. On the left, the graph fluctuated wildly up and down, going from extreme highs to extreme lows. Then suddenly, the graph settled down to mild up and down variations, and became basically horizontal, continuing to the right. Then he labelled the axes. The vertical axis was local temperature for an area where most humans lived. The horizontal axis was time. The time when the temperature settled down to a relatively constant pattern was about 10 000 years ago, the time when the last ice age ended. Then he asked us what other important event occurred around 8000 to 10000 years ago. Of course, the answer was the dawn of human civilization. Human civilization appeared about 8000 years ago. Civilization can only exist because of agriculture. People begin to plant crops in one area. They grow more food than they can eat, so they can have more children. Not all members of society have to spend time farming; individuals can afford to spend time doing other things like making pottery to store extra food, building better houses, or posting on Slashdot.
The problem for cities comes when the conditions that allowed successful agriculture change. Three or four years of failed crops caused by drought or heat or cold or surplus precipitation will exhaust all stored food. The residents of the cities will have to abandon their cities to begin hunting and gathering again, thus largely shattering any nascent civilization. The lesson from this is that human civilization was not simply the result of the triumph of human intelligence over nature. Civilization appeared 8000 years ago because the climate conditions favored it. During the last ice age, the conditions did not favor the development of cities. Even in areas that were not covered in ice, the climate conditions would have been highly variable thanks to the huge persistent ice sheets to the north. One day the air would come from the warm south, another day, the air would come from the cold northern ice sheets. These unstable conditions would have made sustained agriculture impossible.
My second point is that the well known fact that the climate in the past has shifted from warm to cold to warm should not be comforting to us. In fact, it should be the opposite. The fact that the Earth's climate has shifted in the past indicates that our climate is highly sensitive to relatively small forcings. Tiny changes in the Earth's orbit that cause periodically the Northern hemisphere to get more sunlight, and then tens of thousands of years later less sunlight are thought to have forced the Earth into and then out of ice ages (Milankovic Cycles). The slow collision of the Indian sub-continent with Asia, and its resulting volcanism is thought to have caused a large spike in carbon dioxide concentrations, resulting in a climate where the conditions in the north were near tropical.
The fact that the climate has shifted in the past due to relatively small changes indicates that "relatively small" changes wrought by humans, such as the removal of carbon from under the ground and the dumping of it into the atmosphere are capable of pushing our climate into a very different state, one that is likely to reduce human agricultural output by enough to make our current large scale civilization a dubious proposition.
This and no other is the root from which a tyrant springs; when first he appears as a protector - Plato (423 to 327 BC)
I find your humor quite derivative.
W..w..W - Willy Waterloo washes Warren Wiggins who is washing Waldo Woo.