I don’t have the gloomy outlook you do. If the worst happens (which is still not a sure thing)I think we’ll get through it with a little luck; human beings are adaptable, and sometimes they have been able to rise to the occasion. But I do believe the world population will drop precipitously and standards of living will fall to 19th century levels.

My guess is the world leaders which will emerge after such a crisis will be countries with a developing industrial base but with plenty of people still in the countryside who can grow their own food, make their own clothes and build their own houses with a minimum of technology.

I’m betting on India and China, and maybe Brazil.

It will lose every “war” in which it engages unless it does find the troops to keep incountry. We won’t be occupied, but will be isolated and marginalized.

This is not a political post, has nothing to do with any political position it’s simply a guess as to the outcome of forces operating on the human condition.

It will also be gradual, taking generations, so we will be able to adjust. The kind of flooding you can expect from Greenland and Antarctica being ice-free would be devastating, but the violent climate excursions we would experience prior to that would probably wipe out our mechanized agriculture and much of our industrial base long before we had to move to higher ground.

The figure I’ve read for a total meltdown would raise sea levels several hundred feet. I don’t believe in runaway warming, it’s never happened before, why should it happen now? I suspect the Earth’s natural regulating and buffering systems would kick in and prevent that. But I don’t believe just because the worst-case scenario is highly unlikely doesn’t mean we don’t have a very serious problem.

My house is 7 feet above mean high tide, and I live 8 miles from the Atlantic.

I’ve read a few articles that claim sea level “could” rise but don’t bother to say how much or how soon. That’s why I searched for the figures.

But we also know the Earth, and Life, have an enormous capacity to absorb stress, survive damage, and evolve. Earth Abides, as the Good Book tells us. We may get an occasional Ice Age or lose a dominant life form like the Terrible Lizards, but life has never been wiped out. In the long run, it has endured and even flourished. It can adapt itself to just about any disaster, sudden or slow, and the atmosphere and oceans are filled with feedback loops and self-modifying systems which can adjust to change, perhaps at some new level of stability, but stability nevertheless. A 4 billion year history proves this without a doubt.

What is much more likely to happen is that the Earth’s atmosphere and oceans will adjust until a new plateau of stability is achieved, as it has done innumerable times in the past. This process goes on all the time, naturally, even without the provocation of extraordinary events. Global climate changes over geologic time scales just like local weather changes over the course of a year, dramatically, but within limits. The question is can our industrial civilization adapt to keep up with that change within a generation or two?

We can now alter the planet by our presence, our agricultural practices, resource extraction and industrial activities. We can’t be sure what we are witnessing now is evidence of this, but neither should we dismiss it as impossible simply because it hasn’t happened during our recorded history, or because it might be inconvenient for our investments. Most of our stay on Earth has been low-impact. The Industrial Revolution and the population explosion are only a couple of centuries old, a heartbeat in Earth’s history; and we often forget how dependent contemporary civilization is on relatively minor things, like abundant rainfall in the Midwest or sufficient snowfall in the Rockies, or relatively mild winters in Northern Europe. The changes we are seeing now are not going to take centuries and we won’t have time to adjust. Summer Arctic sea ice has dropped forty percent over the last 30 years, this has never happened before, excpt in times of global catastrophe. Perhaps we are that catastrophe.

We can’t count on the rapid changes we are seeing in the Arctic being reversed by natural adjustments, they may continue to affect some of the environmental conditions we have come to depend on. Neolithic cultures could survive in the shadow of the glaciers in Ice Age France. Modern man cannot.

Maybe in “4,000″ years.

Fill a glass of water to the brim and then place an ice cube in it. Excess water will spill over the edge of the glass until the cube floats in a glass filled to the very top. However, as that cube melts, no more water will spill out, because the volume taken up by the cube as it melts is identical to the volume of water displaced by the submerged ice when it is frozen.

All the sea ice at the poles is only a few feet thick, and it floats on water, so its melting will add no water to the ocean basins. It is all the ice on land, mostly in Greenland and Antarctica, that has the potential of flooding the coastal plains where the majority of the earth’s people live.

The major factor, as you point out, is albedo. When the sea ice melts in summer, sunlight striking the poles is not reflected back into space, it penetrates the sea and warms it up. As the ice melt increases every summer, the polar seas warm up making it harder for them to freeze up the following winter. What we are seeing now is an acceleration of the process because snow is not falling on existing sea ice, making more and more ice pack. It is falling into the water. More and more of the ice we are seeing is “new ice”, ice that formed in the most recent winter, as opposed to multi-year ice which has been growing steadily thicker due to freezing below and snow above. New ice is thinner, and more easily broken up and scattered by wave and wind. Although its albedo properties are just as effective as old ice, its thickness and durability is not.

This is why the melting, as noted in those graphs I reproduced, is not just getting worse, its getting worse faster. The winter ice levels are still pretty high (although somewhat lower every year), but the summer ice is disappearing at an alarming rate. I believe it is now vanishing at a rate that will give us our first ice-free summer in the very near future.

Continental ice, however, is thousands of feet thick in Greenland, and miles thick in Antarctica. The continental melting that could flood large coastal areas, if it ever comes, will only become noticeable after the world undergoes dramatic climate shifts in the temperate zones.

Our descendants won’t burn up, or drown, they’ll starve first.