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What Caused a 1300-Year Deep Freeze?
sciencehabit (1205606) writes "Things were looking up for Earth about 12,800 years ago. The last Ice Age was coming to an end, mammoths and other large mammals romped around North America, and humans were beginning to settle down and cultivate wild plants. Then, suddenly, the planet plunged into a deep freeze, returning to near-glacial temperatures for more than a millennium before getting warm again. The mammoths disappeared at about the same time, as did a major Native American culture that thrived on hunting them. A persistent band of researchers has blamed this apparent disaster on the impact of a comet or asteroid, but a new study concludes that the real explanation for the chill, at least, may lie strictly with Earth-bound events."
Cope, yes. Cope inexpensively, no. Coping with a significantly warmer climate will be expensive. There's evidence that we could spend some money now to reduce the warming, thereby reducing the total cost. Wouldn't reducing the total cost mean that it makes economic sense to reduce carbon dioxide emissions?
What a fool believes, he sees, no wise man has the power to reason away.
Tundra soil is not particularly fertile and the processes that enrich soil can take hundreds if not thousands of years. I suppose if you have enough compost to cover Canada and such.
and that ignores the obvious desertification that would happen across huge swathes of currently productive land.
"The prevailing theory is that the Younger Dryas was caused by significant reduction or shutdown of the North Atlantic "Conveyor", which circulates warm tropical waters northward, in response to a sudden influx of fresh water from Lake Agassiz and deglaciation in North America. Geological evidence for such an event is thus far lacking. The global climate would then have become locked into the new state until freezing removed the fresh water "lid" from the north Atlantic Ocean. An alternative theory suggests instead that the jet stream shifted northward in response to the changing topographic forcing of the melting North American ice sheet, bringing more rain to the North Atlantic which freshened the ocean surface enough to slow the thermohaline circulation. There is also some evidence that a solar flare may have been responsible for the megafaunal extinction, though it cannot explain the apparent variability in the extinction across all continents." - http://en.wikipedia.org/wiki/Y...
This headline promises a lot, but delivers nothing. The article just looks briefly at the controversy -- in other words, we still don't know.
This comes from a good Journal, but reading it was a waste of time.
No-one is suggesting the human species won't survive.
Large numbers of individual humans might not.
Bill O'rockly on Foxosaurus News says that theory is a bunch of brontosaurus droppings.
Table-ized A.I.
If Al Gore-like shamans lived back then, the insufficient fervor of the rival shamans in keeping the fires going all day and night would've been blamed for the freeze.
Anybody failing to keep their fire going would be shamed and punished — unless they paid tribute (to buy global freezing offset credits) to the right shaman, of course.
In Soviet Washington the swamp drains you.
Short answer - no.
A longer, more speculative answer can be found here.
The impact of warming on food yields is complex. The latest research suggests that food yields will decrease with a warming of 2 degrees Celsius.
What a fool believes, he sees, no wise man has the power to reason away.
Old Argument (Younger Dryas): We found iridium (rare on earth but abundant in meteorites), nanodiamonds and magnetic particles covering ancient tools and mammoth remains at sites which we believe are around 12,000 years old. Therefore, we believe a cosmic collision caused the 1,300 year deep-freeze.
New Argument: We performed radiocarbon dating on tools found at the 29 sites described in the Old Argument and found that only 3 of the 29 sites were around 12,000 years old. The tools at other sites were much older or younger. Therefore, the deep-freeze was probably not caused by a cosmic collision.
This was caused by my ex- wife..
I have mod points and I am not afraid to use them.
Tundra is marginal for most crops. Tundra is typically a thin, acidic soil. Given a couple of hundred thousand years, it probably would pick up a bunch of new critters and plants and become more organically active, but most of us are not that patient.
Faster! Faster! Faster would be better!
Desertification is not 'obvious'. Key to global warming is more water vapor feeding back any heat increases. Likely increased average rain with increased temperature.
You seem to be making a common mistake when talking about climate change:
You're confusing global "average rain" with local "average rain."
We know, without a doubt, that climate change will shift weather patterns and create deserts.
We're also seeing signs that climate change is shifting weather patterns and greening existing deserts.
For the sake of argument, let's assume that useless land and useful land switch places in a 1:1 ratio.
That still leaves one big problem: what do you do with all the people and infrastructure that are in the new desert?
It's a problem whose only solutions are extremely expensive.
[Fuck Beta]
o0t!
There's so much misinformation in your post it hurts. It's warmed 0.7 degrees Celsius in the past 134 years. It is currently warmer now than any time in the past 2000 years. In the past 17 years Earth has warmed by about 0.1 degrees Celsius per decade. And there's no sign of cooling or even temperatures leveling off.
What a fool believes, he sees, no wise man has the power to reason away.
During the Last Glacial Maximum (only ~23,000 years ago), sea level was 400 feet lower than it is today.
Good thing they didn't have any coastal cities 23,000 years ago. That would have sucked.
In fact, every species that's alive today has managed to survive dozens of glacial advances and glacial retreats
What about the species that aren't alive today? How did they do?
Apparently they're not aware that this is trivial compared to what nature dishes out. During the Last Glacial Maximum (only ~23,000 years ago), sea level was 400 feet lower than it is today.
So the billions of inhabitants of the world's major cities would have been much further away from the coast back then? I wonder how they got their fish?
Better to be despised for too anxious apprehensions, than ruined by too confident a security. --Edmund Burke
But why let facts get in the way of us feeling important eh?
Don't complain about syntax, grammar, or spelling. There is no.hell like input on android.
Nope. Not even close. Closer to 1C since 1940: http://woodfortrees.org/plot/g... . Where on Earth did you get 0.2C since 1940? That's just crazy! We've had almost 0.2C warming during the "pause" of the last 17 years: http://www.woodfortrees.org/pl...
Good thing most of our food grows on ammonium nitrate and very little else.
while(1) attack(People.Sandy);
In this graph from NOAA you can see there's been far more than 0.2 degrees warming since 1940. It looks to be about 0.5 degrees Celsius since 1940. In fact, it's warmed 0.6 degrees Celsius since 1970.
What a fool believes, he sees, no wise man has the power to reason away.
Lucky for you there is only 1 country in the world.
But we have already seen the problem in your 1 tiny world. New Orleans is already under water and you were too stupid to move it the first time. You already have cities in stupid places, it will only get worse. What if the climate changes and New York ends up with massive frequent flooding and all those extra people?
DRINK!
Ooh, moderator points! Five more idjits go to Minus One Hell!
Delendae sunt RIAA, MPAA et Windoze
The science is working, if the scientific knowledge keeps enabling new revolutionary technologies (genetic engineering, nanotechnology, metamaterials, energy storage technology, quantum computers...) like it has been doing for as long as scientific method has been applies in large scale (radio, electricity, plastics, advanced alloys, computers, telecom, crude genetic engineering, satellites...).
That's a pretty good benchmark really. Just being able to read opinions of all the anti-science people proves science works, because if it didn't, they'd be restricted to climbing on shoebox and shouting.
And luckily, everybody in the world lives in the US.
Don't be ridiculous. They'll survive just fine. Their property holdings may not. It's not going to flood overnight. There will be ample warning.
Good thing they didn't have any coastal cities 23,000 years ago. That would have sucked.
There were plenty of coastal cities, well, villages in most cases due to lower overall population.
The main point however is that ... cities do die over time due to environmental changes, this is in no way 'new' or unique to modern society.
Persistent Volume manager for Kubernetes - https://github.com/dwimsey/openshift-pvmanager
Tundra is not marginal.
Yes it is.
You seem to lack a basic understanding of what it is. Permafrost has been frozen for many thousands of years. The biological processes (re: bacteria) that break down organic materials into nutrients that make for fertile soil are not active and present. They take time to occur and spread and actually create thick deep rich soil, the kind you need for farming.
Tundra will become forest, .
No, it wont.
Or rather, it's not a given, and even if it DID occur, you're talking about a process that will take several centuries on its own. Not exactly something we can just wait for realistically.
forest will become fertile farmland..
Again, no. ...basically nonexistent.
Your understanding of agriculture, soil health, forestry, etc is
In fact, strike "basically". It is nonexistent.
Desertification is not 'obvious'. .
Yes it is. It's happening before our eyes.
Key to global warming is more water vapor feeding back any heat increases. Likely increased average rain with increased temperature.
Ah, the old "more rain = good".
First off, its not more rain period.
Many area will get less rain, as they get pushed to the opposite extreme. Death Valley wont suddenly find itself pushed to wetness. In fact the opposite: Death Valley type conditions and dryness will cover a larger area in similar circumstances (rain shadows more severe, etc).
In other areas, they will get more rain. But more rain isnt automatically good. Too much rain too quickly doesnt soak in, but causes flash floods, erosion, and mudslides, stripping good soil off the surface, and clogging streams and rivers with sediment. This process expands river deltas, which are fertile, but leaves the interior with less arable land.
The guy who said the election was rigged won the presidency with the second-most votes.
What I have heard of so far in terms of likely submerged human settlements is the Black Sea before the Mediterranean spilled into it (possibly the origin of the Noah story), and land to the east of England.
Also quite a few indigenous villages now underwater around the coast of Florida.
This is not a agenda free site.
Amazing that they don't seem to know that the reason there is a process to estimate terrestrial temperature using tress is because a solar astronomer named A. E. Douglass wanted sun spot data for periods from before modern times when sun spot data was recorded. He worked out that because sun spot activity effected climate, which resulted in larger tree rings for years with high sun spot activity, that he could use old growth trees to determine sunspot activity for earlier periods.
Later in the 1990s climate change supports started using his data, which he had already proved was linked to sunspot activity to support AGW. How did he prove his theory? He used the scientific method. He compared periods of known correlation and then predicted future activity. When his prediction came true he then used what he had learned to map previous sunspots periods. So climate is linked to sun spot activity. You can even see it now. the early 2000s was a low sunspot activity period, and there was no average temperature rise. The 1930s were high sunspot activity periods. The 1930s were warmer than the 1990s'
Climate scientist could learn a lot from A.E. Douglass, since their methods seem to be ignore data that doesn't fit the hypothesis, create models that don't really match predictions, and blame people who then don't believe you.
What I have heard of so far in terms of likely submerged human settlements is the Black Sea before the Mediterranean spilled into it (possibly the origin of the Noah story), and land to the east of England.
Partial list of submerged human activity:
Doggerland was a rather large land area containing a not-insignificant amount of human activity, which now lies under the north sea.
Sundaland is another large landmass that is now submerged, with an unknown but suspected to be significant quantity of past human activity.
Coquer Cave off the coast of France is an interesting site, containing paleolithic cave paintings that can only be reached by diving.
The Black Sea is hypothesized to have expanded in the past, covering an unknown quantity of human archaeological material. The extent and suddenness of the expansion are currently subject to debate.
The original peopling of the Americas has been hypothesized to have been impacted by a coastal migration route, but much of the archaeological evidence (if it exists) for this hypothesis is currently under water.
Beringia itself, suspected to be the cradle of the Native American peoples, is now partially submerged under the Bering strait.