Humans Nearly Went Extinct 70,000 Years Ago 777
Josh Fink brings us a CNN story discussing evidence found by researchers which indicates that humans came close to extinction roughly 70,000 years ago. A similar study by Stanford scientists suggests that droughts reduced the population to as few as 2,000 humans, who were scattered in small, isolated groups. Quoting:
"'This study illustrates the extraordinary power of genetics to reveal insights into some of the key events in our species' history,' said Spencer Wells, National Geographic Society explorer in residence. 'Tiny bands of early humans, forced apart by harsh environmental conditions, coming back from the brink to reunite and populate the world. Truly an epic drama, written in our DNA.'"
The way things are going (Score:5, Insightful)
Environmental damage here we come!
Re:The concept of races (Score:5, Insightful)
Re:The concept of races (Score:5, Insightful)
Re:The way things are going (Score:4, Insightful)
we will actually reach that population level again. Environmental damage here we come!
I knew someone would say this. Alright, I'll bite. Name one plausible environmental damage scenario (other than full-out nuclear war) that would cause a significant proportion of human extinction.
The most extreme predictions of global warming will hardly slow down human population growth, much less actually reduce populations, much less threaten us with extinction. (Of course, predictions are that human population growth will naturally slow and even stop over the next 50 years, but that's another subject).
Re:Are we SO sure? (Score:5, Insightful)
I think that this is actually plausible. Things to mull over that could make this an interesting topic:
1) What evidence, 70000 years later, would decisively display the difference between a flood and a drought?
2) Could the Noah story be an allegory written after the fact to describe this event, with only the details mixed up? If so, what does that tell us about this story?
3) What remnants of an Ark would one expect to find 70000, or even 5000 years after the fact? Conversely, what evidence could be shown that would decisively PROVE OR DISPROVE that the event happened? And I'm talking about scientific evidence here. Not anecdotal faith-based cruft. Not even science-based faith-based cruft, if you please...
Love these topics. Go people, go!!
Population bottleneck, and his name is Noah (Score:3, Insightful)
Re:So...the Neanderthals could have wiped us out (Score:5, Insightful)
The problem with these studies is that there isn't any DNA record of the humans that didn't make it. The only evidence we could hope to find of the humans that have died out is fossilized remains, which are few and far between.
Re:The way things are going (Score:5, Insightful)
How about the people who busily insist that can't possibly be anything other than a wholly human-caused phenomenon, and that we can definitely stop it. What if we can't? Plans, anyone?
Seriously, I want my interstellar settler permit and associated vehicle already...oh, wait...we can't even go to the moon anymore.
Re:The way things are going (Score:3, Insightful)
1. CO2 is a very minor greenhouse gas
2. The amount of CO2 re release into the atmosphere is pathetic compared to the other gases - a mere 0.28% 3. The hottest years on record predate the industrial revolution
4. There are a number of other factors such as the above that you can't/don't give an explaination for (solar activity being one), and you simply resort to either the "your workin for big oil" or the "i'm more rightgous than you" defense, neither of which is a valid scientific defense.
Re:The way things are going (Score:2, Insightful)
The economic impact of the kind of changes global warming devotees are demanding far exceeds $100 per devotee. At minimum, the negative impact on developing economies and the resulting harm to the poor of the world should require that you kill yourself as well if you're wrong.
Re:The way things are going (Score:3, Insightful)
Maybe something like an airborne or mosquito-borne variant of HIV?
It's certainly possible to get killer diseases, but that's not an environmental damage scenario. That can happen anytime.
Re:So...the Neanderthals could have wiped us out (Score:5, Insightful)
What a difference 70,000 years makes!
Re:The way things are going (Score:5, Insightful)
Might as well give up now and save a few billion dollars.
I'm of the opinion that GW is natural and we are just giving it a teeny tiny push.
Next they'll blame the next ice age on human activity as well.
Re:The way things are going (Score:5, Insightful)
The global cooling issue was a 1 time tabloid issue. It was never in the science world other than 1 article. Only idiots point to that.
In the 80's, it was reagan trying to roll back the environmental changes (interestingly, the majority of the environmental laws esp EPA was from the pubs). It was the beginning of the ozone issue.
In the 90's, it was solving the Ozone issue. And just all the other ones was a problem. Fortunately, it is being saved because the freon was stopped. But we still have a hole in the south pole, that is slowly receding.
And since the 90's, global warming has been an issue. Back in the mid 90's, the neo-cons said that the earth is not warming. Now they say that man can not be behind the warming.
Do not buy it. Just quit polluting and forcing your shit on me and mine.
Re:The way things are going (Score:5, Insightful)
I presume that you love America? And perhaps by extension that you love our national symbol, the bald eagle? Well the only reason you can see them in the wild today is because of the DDT ban. They are one of the few species to ever come back after being placed on the endangered species list, and it's directly due to environmental action. So I'd hope you'd show a little gratitude.
I've heard convincing arguments that an outright ban on DDT went too far, and allowing small-scale controlled usage would have been beneficial. However the large scale cause-and-effect of spewing tremendous amounts of DDT everywhere -> bald eagle populations dropping, and banning DDT -> bald eagle populations recovering is indisputable. We know it was the DDT; we could measure it in the corpses of their prematurely dead young.
Other than that... Global Cooling was not actually a mainstream theory. Pollution/Smog was a serious problem, ask anyone who lived in L.A. in the 80s and now compared to now thanks to their emissions regulations. The ban of CFCs has had a demonstrably positive effect on the condition of the ozone layer.
So you're basing your decision to not believe in Global Warming based on a series of things which mostly turned out to be completely true?
Good job!
Re:The concept of races (Score:3, Insightful)
Re:The concept of races (Score:5, Insightful)
Also, keep in mind that the genetic evidence is just one line of evidence, and that's it's difficult to interpret. If their conclusions are correct, then other lines of evidence should corroborate their story. In particular, if humans nearly went extinct 70,000 years ago, then shouldn't we expect to see that in the archeological evidence, with stone tools becoming less common for a period?
That's definitely a problem I have (Score:5, Insightful)
1) What if even though we are the source, we can't stop it? What if it turns out there's just no way now to turn things around, we are too far down the road? What then?
2) Assuming historical extrapolations are right, the world has been much hotter and colder than it is now. Thus it is likely that will happen again. Thus no matter what we do, we are probably in for a big temperature change at some point.
So then if we assume it is true that a temperature shift of a few degrees will really screw us over, then we need to be preparing for it and figuring out how to deal with it. It really seems like a case of not if but when. Even if we are the cause and have the power to prevent this current change, a change that we can't will happen at some point. Also, just because we are the cause, doesn't mean we can prevent it.
Either way, the most sensible thing would seem to be to figure out what we need to do to be able to survive a temperature shift, not concern ourselves with what the cause is because unless we are extremely incorrect about past temperature, it is not a static function over any time period, and thus is not likely to remain so, regardless of what we do or don't do.
It bothers me (Score:4, Insightful)
Where's the beef? Why are people saying that we're going to see cataclysmic changes in our environment, when no appreciable changes have occured so far. What is the basis for all these predictions?
Re:The way things are going (Score:1, Insightful)
History constitutes less than 2000 years. Thats the farthest back for which there are any usable records.
Nothing known to science allows temperature measurements with the kind of accuracy you claim for other than the last 200 years.
There is nothing to suggest current global temperatures are optimal.
Re:The way things are going (Score:1, Insightful)
Re:The way things are going (Score:5, Insightful)
As for diseases, there is no earthly disease that kills 100% of its victims, (because such a disease would then itself become extinct).
I think you've been watching too much Science Fiction.
You are not legend.
Does intelligence have survival value? (Score:4, Insightful)
Are we going to find life on other planets but discover that high intelligence is rare?
Re:The way things are going (Score:3, Insightful)
Re:So...the Neanderthals could have wiped us out (Score:5, Insightful)
People don't "intermingle", they have children. If the children die, or all the children's children die (or all the children's children's children die, ad inifinitum), then your unique genetic code is erased (except the portion of your genetic code that you shared with other individuals who got it through a different path in the graph).
In fact, it's slightly more complicated than that because when you have children you only pass on (an essentially random) half of your genetic code. You might have the dumb luck that none of the unique mutations in your code gets passed on to your children because they never land in your children's 50%. You therefore might have had a unique mutation that cannot ever be detected in the future genetic record because by chance you passed on the "common" portion of your DNA code and not the unique mutation.
So yes, branches of this DAG can and do die off. Nothing "points" to them, so they die. In fact, this is the very mechanism by which natural selection and speciation occurs.
The arguments they use in the article are statistical and even though they account for many factors, in the end they can only work on information available from surviving DNA.
Re:The way things are going (Score:5, Insightful)
Re:The way things are going (Score:5, Insightful)
Re:The way things are going (Score:5, Insightful)
B: Yes. The era of planet formation was pretty hot. Your point?
C: The industrial revolution predated worldwide temperature monitoring. The "record", such as it goes, it incomplete.
I'll have to beg your forgiveness; the "global warming isn't a threat / is not our fault" line has been embraced by the same slice of the body politic that claims DDT doesn't hurt baby eagles, smoking doesn't cause cancer, and you can cut taxes forever and still pay for a war.
If when you argue on the same side of an issue as those who have long since ceded any claims to credibility to the scientific method, you get associated with their tactics until argued otherwise. "Silence implies consent", and all.
Re:The way things are going (Score:3, Insightful)
And that's ignoring that the loudest reactions to Global Warming have never been ethanol, but conservation and pollution controls instead.
Re:The way things are going (Score:5, Insightful)
Be careful saying that. You're likely to get yourself harassed, blacklisted, and shunned for such politically incorrect remarks.
I fully believe that the greenhouse effect is a simple matter of physics. I also believe that the effects, as we know them, do not occur rapidly. I also know that, historically, the climate is NOT stable - whoever said that it's been stable for most of history simply does not know history (Nineteen-hundred-and-froze-to-death being one example, the total environmental collapse of mesoamerica and the middle east, the sudden shift that made Europe more habitable and helped lead to the Rennaisance, etc etc etc).
In other words, yes our pollutants will have a very real effect on our climate. There is no free lunch. But, those effects belong to our children and grandchildren - what you see today is the normal cycle of change - but in a highly connected world prone to panic and fantasy, and overly willing to lay blame anywhere it can.
It may not be all bad though... it might scare us into actually controlling ourselves - before the bill actually shows up.
Re:The way things are going (Score:5, Insightful)
I've read this sentiment many times, and although I agree with the latter statement, I can't agree with the former. In my view, it's not a distribution problem, it's an economic problem. We could distribute enormous amounts of food anywhere on the globe, but we don't. Why? It's too expensive. Hungry people are often poor people, and poor people can't pay enough to meet our expectations of a return (or even no loss) on labor, fuel, vehicles, storage, and other distribution resources. So, we make this choice: they're just not valuable enough to us to bear the cost of sending food (of course, aid agencies disagree and do exactly this).
Re:The way things are going (Score:3, Insightful)
Ever wonder why the word "coincidence" often has the phrase "just happens to" associated with it? Have you ever wondered why it matches when we *started* figuring this out and were barely using it versus when we were/are at peak usage? Seeing as how volcanoes have more of a measurable and directly observable impact than anything we've ever done, I'm not really buying the whole "mankind burning oil caused this" hypothesis; one good eruption and our global temp has the potential to drop by 1/2 degree or more, yet somehow we're supposed to have some form of effect that is (not so)surprisingly not so easy to observe and/or correlate.
Re:The way things are going (Score:5, Insightful)
Do you really think that ? I don't.
Considering human acts the main cause of global warming (or whatever other catastrophe you want) is very comforting. Why ? Because we can do something about it.
On the other hand, if humans are not the cause, we have a really big problem. Imagine it is some kind of change on the sun. How do we handle that ?
These days, I take a great deal of comfort on the idea we are destroying out planet, our "natural" disaster are due to humans doing this or that.
Re:The way things are going (Score:3, Insightful)
The most common argument against any questioning of global warming is to claim that the questioner is somehow not intelligent enough to understand. It's second only to immediately accusing any questions of being paid for by Big Oil.
Disregarding GM-Hath-Come theories as preposterous isn't a wise move, but blind acceptance of what the media tells you to believe, in the absence of hard evidence (such as an impossible-to-hide global warming trend that can actually withstand scrutiny and debate), is just as foolish. There's plenty of suggestive evidence, but suggestive doesn't cut it when it comes to claims of absolutes.
The changes are suddenly coming very fast, and people want to know why - even though there's some pretty friggin scary things going on right now (such as marked increases in tectonic activity, unexplained changes in solar activity that violate 200 years of observation, and other observable items that have nothing to do with pollution).
(on a side note, while CO2 is the popular (and quite effective) greenhouse gas, it's not the one you have to worry about. Methane is far more effective at the job, and is put out in massive quantities - by agriculture.)
Re:The way things are going (Score:3, Insightful)
However, along with this big temperature increase we ALSO have an entire body of scientists with models that seem to describe past events really, really well - and even have a pretty decent track record over the last 10 years. These models ALSO implicate man-released CO2 in the warming.
So now the word "coincide" and the phrase "just happens to" look less and less applicable to the situation.
Volcanoes do not spew out as much CO2 as you seem to be implying. Their climate impart predominantly seems to come from ash. If volcanoes spewed out huge amounts of CO2, then the observed CO2 in the atmosphere would spike whenever there was an eruption, and this has not been observed.
Re:It bothers me (Score:4, Insightful)
"(over population is so much more of a threat)"
It is impossible to go extinct due to overpopulation. It is the secondary effects of overpopulation (such as global warming) that cause problems.
Re:It bothers me (Score:5, Insightful)
How would overpopulation end us? Even if you aren't optimistic enough to assume that technology will provide a solution (it always has in the past -- think you could support modern day population density with the agricultural technology of ancient Rome? Hint: You couldn't), how will overpopulation end the human race?
The absolute worst case scenario that I could envision is a global war for resources that the poorer/less-well-armed nations would lose. Even in that scenario I don't see the end of the human race -- it's unlikely that even a global nuclear exchange would end the human race, though it would certainly set us back a few centuries.
Re:The way things are going (Score:2, Insightful)
Name three, and point me to published papers detailing their internals.
I will guarantee certain things.
1) The models will have energy conservation imposed by hand, probably by adjusting the temperatures.
2) There will be large deviations in their predictions for some variables (tropical cyclone frequency, for example)
3) There will be crude parameterizations for important physical processes.
Anyone who believes that global climate models have any predictive value is talking moonshine. Although they are works of scientific art, it is simply false to claim that they are in any but the crudest sense physically realistic.
Have a look at "Taken By Storm", for example--co-written by a mathematical physicist--to get a layperson's sense of some of the problems. It is extremely unfortunately that climatologists didn't spend a few decades modelling much simpler systems before making strong pronouncements on the basis of their models. Computational physicists who look at GCMs all come away just a little bit queazy when they see how this particular sausage is being made.
Re:It bothers me (Score:5, Insightful)
The biggest short term impact of northern cap melting away is albedo. The caps radiate away a far amount of energy because of the snow and ice. Less snow and ice, means more darker surfaces which means more energy is retained. This becomes a feedback loop that rapidly (relatively speaking) ends up warming the northern hemisphere.
You're writing like you don't understand how significant even small changes in global temperatures can have large impacts. Do yourself a favor and read the IPCC reports. Better yet, go enroll yourself in a university and major in climatology. Then you will understand exactly how much energy a 1 degree rise in temperature world-wide can have, and why it should be a concern.
And stop confusing climatology with meteorology. The climate doesn't shift over the course of a week. The changes people are concerned about will be happening over the coming decades and centuries. We only have a hope of preparing for it if we start early.
~X~
Re:Are we SO sure? (Score:3, Insightful)
Mitochondrial DNA (Score:5, Insightful)
Re:The way things are going (Score:2, Insightful)
*SIGH* Not one event you cited was climate related!
1900? How is one year ever indicative of climate?
The collapse of the middle east and mesoamerica... Their cropland collapsed due to their irrigation practices... [tececo.com]
The renaissance was only possible because of a population explosion that happened around the end of the medieval warm period. That happened because of a little invention call crop rotation. Human ingenuity... the warm weather was simply a bonus.
Oh noes!1 I'll be shunned by the cult of global warming. The unspeakable horror!
Re:The way things are going (Score:3, Insightful)
Re:The way things are going (Score:3, Insightful)
As for diseases, there is no earthly disease that kills 100% of its victims, (because such a disease would then itself become extinct).
This is not even mathematically true, much less practically true. If the population of hosts grows at least at the same rate as the spread of the pathogen, then both can continue to survive even with a 100% fatality rate.
Re:Conversation with government clerk.... (Score:3, Insightful)
Call me naive, but is this a question that is actually asked? In what situations? For what purpose?
I'm not from the US and do not know all your local customs, but I find the idea quite absurd (bordering on offensive).
Re:The way things are going (Score:3, Insightful)
But there's more to it than that. Even in places where there isn't unrest but hunger, we do them a disservice in the long run by dumping free food on them. After all, consider a farmer in such a country. He works hard, probably has to take out a loan for seeds and farming materials, and tries to bring his food to market. Then the USA comes in and dumps a few tons of free grain on the people. Who is going to buy the farmer's food if they can just get it for free? By feeding them, we do a lot to keep them in a cycle of poverty and dependence. I'm not saying that we shouldn't help them, but we should also make sure we aren't stifling them and making them dependent upon us. They're only going to really stop being hungry when they can support themselves, and so we're stuck in a really awkward situation where helping them too much would make them worse off in the end.
Re:The way things are going (Score:3, Insightful)
What if it doesn't change a thing? Well, then we've got cleaner air, cooler tech and quieter cars. And we should start finding ways to adapt... But, what if it DOES solve the problem?
If you're going to ponder "what ifs", then at least consider both possibilities!