Dung
Over the years I sometimes thought about a return to a glacial phase of the climate. In my opinion much more likely than any other scenario. If I understand thing correctly, sea-levels in a glacial phase are about 400ft lower than current levels. This increases land area in various parts of the world, Australia and parts of Indonesia being a single landmass for instance. Japan having or nearly having a land bridge to China. So land lost to ice might well be totally regained as a result lower sea-levels. Not that this would prevent conflict.

So with ingenuity in plant and energy technology I'm pretty confident that a human population in the billions could survive a "normal" glacial period. Whether many of the current populations of Northern Europe and North America would survive is debatable. The tundra at the edge of the ice sheet although not much use for food production could well be used for manufacturing of machinery and equipment used for food production in the tropical areas.

I've no real proof but I think that precipitation would be reduced and extracting and transporting water from the ice sheets might become a major activity, probably easier and cheaper than De-salination.

If it's as close as 100 years away there isn't a thing we can do except think about it. If it's ten thousand years we can't even imagine the world at that time, except to know for 100% certain sure that somebody, whether human or not, will be using the crisis to justify central control of everything..

Dung,
I stick with my prognosis that an Iceage similar to the last few wouldn't on its own mean the end of the human race. The possibility of moving elsewhere within a couple of hundred years is unlikely. 500+ years out who knows what technologies will be available, Nor do we know what the human population will be. Hopefully the Ecomentalists will have failed and health, wealth and well being will be the norm for most of the population. The brief period of population exp;osion which every nation experiences when infant mortality is reduced and society takes a couple of generations to switch from 20 births per couple to 2 births per couple.

It's interesting that the last two winters in North America which have been pretty severe, near record amounts of ice on the Great Lakes, have been most severe over the area covered by the Laurentide Ice Sheet during the last glaciation This might be a cause for concern.

If you want to scare yourself then regular visits to http://iceagenow.info/ are recommended. Also reading stuff like this might worry you.

Dung,
I'll see if I can dig up some more links. From what I remember the "snowball earth" has only happened a couple of times, and even that is open to debate. Also in very rough terms the Glacial periods last about 100-150K years and inter-glacials (warmer periods in the current cold period of earth's history) about 10-15K years. But some inter-glacials are missing. Compared with all of Earth's history the current inter-glacial periods aren't particularly warm.

Like a lot of my interest in these things, my interest was originally piqued by a radio programme, which claimed the original, or at least early, work was carried out in a Czech Brick Works; unless my memory is confusing things.

Dung
I found the name of the researcher and the Brickyard, the date is good too as I would have heard of the work in the 1970s.

By about 1968, research on loess deposits shed more light on the pulsebeat of climate. It turned out that loess deposits are not the result of just one glaciation. They sometimes contain a record of many glacial cycles. Ice Ages: Solving the Mystery describes the investigations of a geologist name George Kukla in 1968 at a brickyard quarry on Red Hill near the city of Brno in Czechoslovakia:

http://corior.blogspot.com/2006/02/part-15-ice-ages-confirmed.html

Dung
For clarification, what you mean by a Glacial Period is the "current" situation where there are ice-sheets at the poles and where there is permanent snow at high altitudes, both altitude and latitude. We are still in a glacial period despite reduced ice cover? In terms of the Earth's history I guess you are technically correct.

In these papers and to most people we're in an inter-glacial period where the ice has retreated to higher latitudes and altitudes. The Iceage is when the ice sheets have advanced to lower altitudes and latitudes. Hence the "Little Iceage" during which there was an advance just not as far as has happened in the full glaciation periods. For my lifetime I have followed this nomenclature, which is what most published papers do.

I think there are two questions, with regard to glaciation and what will happen in the future.

1. What causes/caused a part of the planet to have permanent ice cover
2 What causes periodic advances and retreats.

Is the second and how we deal with it is what you're interested in?

There may be more than one factor in each, in fact it is almost certain there are. For our immediate future finding the major cause of advances is more important than wasting time, money and effort looking in to CO2 and its affect on climate.

Have I got that about right?

Dung
Thought that this item from Steve Goddard might interest you. Especially as the BBC is the source in 1975. There's also a video clip I'm the comments which is interesting as well

https://stevengoddard.wordpress.com/2015/02/27/1974-bbc-warned-of-a-new-ice-age-within-our-lifetime/

Dung

I would be grateful for any suggestions as to how we keep mankind safe

I don't really think mankind deserves to be kept safe at the moment, so I suppose you can put me
in with the fatalistic crowd.

There's nothing inherently unscientific about the technicalities of getting to other planets etc. or even
of shifting earth orbit - I expect this is something we could even do now given enough resources,
let along within 10,000 years - e.g. we could alter earth's orbit by dislodging a few large asteroids to
have close approaches with earth to impart some orbital energy, for example.

It's the quality of our civilisation I doubt is worth saving. The Enlightenment seems to be guttering
out. All over the world, people care less and less about the search for knowledge and art. The majority
of people don't care about the great questions. We are little more than animals, clever animals with
opposable thumbs, but not much more between the ears.

Not worth saving, in my opinion.

Dung,

As for surviving an ice age, man has learned to adapt to most earth habitats even without high technology - there are native peoples living within the arctic circle right now who don't have much technology and still manage to survive. I don't have any doubts that humans can and will survive another glacial, we've survived hundred already - but will our society and civilisation survive is the pertinent point.

I think the most telling aspect will be how quickly the glacial comes on, these things look dramatic on a graph with an X axis measured in ticks of thousands of years, but the reality will likely be a very slow creep. The tundra line will creep southwards, pushing agriculture towards the Mediterranean, but this will be expressed in generational stories of crop failure and migration that's no different from modern ones, like the Okies in the 20s.

I don't believe it will ever happen. We will have complete mastery of the earth's climate long before then. Just because the modern crop of 2nd rate climate scientists have no clue, I don't believe this will always be the case, just like the physicians of only 200 years ago were stabbing you with sticks and letting leeches suck on you, but this doesn't mean modern medicine was not in the future. Someday, we will understand climate, and be able to control it.

Dung/TBYJ
The history of humans is a series of rises and falls, with a general progress to greater development of well being. There is no reason to think that there isn;t a step backwards in the near future, without an iceage to focus the mind. The potential for the current religious friction to end up with a result similar to the effect Sea People/Peoples of the Sea/Sherden had on Bronze age civilisations is quite high in my opinion. Again probably more of a threat than CO2.

Being an optimistic person I think that humans will survive in one way or another. Nor do I think the current situation is that bad, given the choice of living now and any other time in human history I think I'd choose now. To me that is progress, although people in some of the slums of the developing world might think differently, but I seriously doubt the majority would. The option of a a Green Utopia just round the corner doesn't hold any attractions.

The rejection of Nuclear Power by the majority can easily change when faced with a life and death choice. I liken the problem to my children and grandchildren's diets. One is a vegetarian, one won't eat fish and the grandchildren are more selective. I tell them it is only wealth that allows such choices, if or when the nation becomes too poor then they'll quite happily eat all the things they reject now, as the other option is to die.

As previously stated a large icesheet over the northern hemisphere is compensated by lower sea levels and more land elsewhere. The human population works well under the pressure of life or death situations, note how technology takes quantum leaps in times of war.

But I do worry that we might end up in a perfect storm of approaching Ice and religious conflict (Sea Peoples) coupled with Greens in control.

If an Iceage lasts 100K years then the humans that make it into the next interglacial will be very different from those that came out of the last.

Sandy,

You touch on another aspect of modern society which I think it part of our problem at the moment.

As much as we like to seek out peace and harmony and think they are admirable ways to run
society, ALL of mankind's advances are brought about by struggle or some sort. We have only
gotten to where we are now because of a series of struggles against an inhospitable environment,
then the dog-eat-dog world of the animal kingdom, disease and eventually internecine struggle
against other tribes of man.

Part of what I believe is the "problem" with current society is that we are 70 years away from a
real existential war, we've conquered most of the major killer diseases, and the gradual shift to
a more equal society means people (by and large) no longer starve if find themselves out of work.
Nuclear power came out of the war effort. The moon landings came out of the cold war. We
are stagnating because we have no real threat or personal danger any more. When communism
fell, so did our desire to strive for advantage.

Mankind thrives under the pressure of existential threat. I believe this is what drives the Millenariast
cult of AGW. Because we have no problems which can unite and inspire us, one had to be invented.

Unfortunately for the cult, AGW is not the one we should have been worried about. Whilst we were
squandering our money on a fake threat, militant Islam and a regressive Soviet mindset has arisen to
fill the gap of the greatest confrontation of the next century IMO. Soon enough we'll have to be striving
for all our worth.

Forgot to add: So in summary, I think we thrive under existential pressure. If the ice age cometh.... bring it on!

TBYJ
We need something to divert the human race from pressing the one step backward button fairly soon. Religious fanatics of modern and traditional religions are taking us to hell in a handcart in short order.

Dung
Neanderthal survived in the part of Europe not under the ice for about 100k years. They.managed this without developing technology much further from the stone hand axe. So it's my view that if Neanderthal man can do it then we should be able to do it. Which isn't to that we will. We have a lot ok knowledge on how to produce energy and from that to produce food.

Remember one of the problems we have with extreme weather events = AGW is that most people think that if they haven't experienced it then it's never happened before. Also my children think that Oil Seed Rape has been grown forever, whilst I can remember the discussions over the bright yellow fields that started appearing from nowhere. What I'm trying to say is that people are very good at believing a changing world is unchanging. This is a good survival mechanism as it helps the endeavour of surviving serious environmental changes. The Sea Peoples, the fall of the Roman Empire, the fall of Mayan Empire and Black Death all caused a step backwards in many respects. But what emerged afterwards was a step forward. All of these events were unexpected and unplanned for whereas with an ice-age there is plenty of advanced warning.

The mile thick ice was water at one time, therefore the oceans sea level will fall by a considerable amount, much of the exposed land is in the current tropical zone. This will be the area least hostile to survival. So unless there is a snowball Earth or we self destruct (which doesn't require an ice-age) then there is a good chance we'll survive and continue evolving

Dung,
that's a pity, i was quite enjoying the research.

The Snowball Earth is quite interesting. So I might continue the search for information.

I did discover an article where the cooling effect was put down to the O2/CO2 ratio being close to unity. This caused cooling which is something people say about CO2 that it actually cools the climate. Again something worthy of more research (on my part).