Did climate change nearly wipe out humans only 70,000 years ago?

Question

That’s before SUVs, George Bush and private jets for rich liberals, right?

So, who will we blame it on?

Human beings may have had a brush with extinction 70,000 years ago, an extensive genetic study suggests. The human population at that time was reduced to small isolated groups in Africa, apparently because of drought, according to an analysis released Thursday

The report notes that a separate study by researchers at Stanford University estimated the number of early humans may have shrunk as low as 2,000 before numbers began to expand again in the early Stone Age.

… Paleontologist Meave Leakey, a Genographic adviser, commented: "Who would have thought that as recently as 70,000 years ago, extremes of climate had reduced our population to such small numbers that we were on the very edge of extinction."

Answer 1

Where is the study?  Would you mind providing a link so we can read it for ourselves?  I don't think anyone here is inclined to form an opinion based on  these excerpts.

I think it's important to recognize that the term "human" can and is defined differently for different purposes.  It can be used to mean modern humans, or homo sapiens.  They evolved 10,000-15,000 years ago during the last ice age, which some think caused their appearance.  There has been a small but measurable increase in brain size since the originals, but no other major changes.  The only serious setback as a species that they have suffered (that we know of) were the great plagues of the middle ages.  Modern humans didn't exist 70,000 years ago.

If you want to look at earlier ancesters of Homo Sapiens as your study does, in the last 1 million years you have the parent stock, Homo Erectus.  Within Homo Erectus you have numerous other individual species, scattered all over the world.  We are the most recent to branch off the Homo Erectus bloodline.   Homo Neanderthalensis  (Neanderthal Man) branched off before us, and is a relative, but not an ancestor.  The Neanderthals were the dominant species for around 350,000 years, compared to our 10-15,000.  Modern humans coexisted with them and other species of Homo Erectus.  All were tool makers and used fire.  All are sometimes called "human" because they carry some or all of the traits that define Homo Sapiens as a species, although they are not of our species.

At the million year mark you have Zinjanthropus boisei discovered  by Louis Leakey in 1959 (I was in middle school and was thrilled).  Meave is the wife of Richard Leakey, who is the son of Louis Leakey.  Zinjanthropus was the first clearly human ancestor clearly much older than Homo Sapiens or Homo Neanderthalensis.  It completely changed the way we look at the term "human".  It was quickly possible to classify other species similar to Zinjanthropus within their own branch of human evolution.  Many of these had been found as fossils, but couldn't be definitively classified until Zinjanthropus.  Up until then it could still be argued that they were not human, just similar to humans.  That parent stock of which Homo Erectus is a branch is called the Australopithicines.  Zinjanthropus was an Australopithicine.  Most of the species within this grouping used tools, and some used fire.  Fire is thought to have been "discovered" about 800,000 years ago.

The Australopithicines at this point have been traced back 4 million years at this point, and include several known species, and no doubt others yet to be discovered.  Homo Habilis, who lived about 2 million years was strikingly similar to modern humans.  Prior to the Australopithicines several species have been discovered with the defining human characteristics.  Current work is to discover others that can be organized into the parent stock from which the Australopithicines diverged.  The overall bloodline, or "family tree" is called the Homonids.

The Leakey family has kind of made the exploration of early human ancestry their family business.  They generally leave Homo Sapiens to others.

So my point is, during this 4 million years there have been many climate changes that doubtless affected these various species in major ways.  It is strongly believed that the last major ice age was the "trigger event"  that caused Homo Sapiens to branch off from the Homo Erectus branch of the Australopithicine branch of the Homonids.  It is therefor not only  possible but probable that earlier climate events triggered other branchings critical to the evolution of the modern human.  Biologists no longer believe as the "Darwinists" once did, that evolution moves at a very slow pace pace over long spans of time.  Stephen Jay Gould devised the "punctuated equillibrium" theory, that species tend to exist unchanged for long periods of time when not presented with an environmental challenge.  When presented with an environmental challenge they either evolve rapidly, or are replaced by a different species.

Peace.

Answer 2

Quite possibly. Climatic cycles have been operating on this planet for a long time.

Climate change is a money and power grab scheme by the bottom feeder politicians and power brokers. It's nothing to do with ecology and everything to do with money.

Con artists like Gore have enriched themselves on this issue, taking home Oscars, Nobel Prizes and millions of dollars. Meanwhile, evangelical leaders are setting up their flocks for extreme fleecing by leftist politicos like Barack Obama, who will appeal for Christian votes by talking in glowing, biblical-sounding terms about "being good stewards of God's creation."

Here is truth about global warming:

Global warming is one-half of the climatic cycle of warming and cooling.

The earth's mean temperature cycles around the freezing point of water.

This is a completely natural phenomenon which has been going on since

there has been water on this planet. It is driven by the sun.

Our planet is currently emerging from a 'mini ice age', so is

becoming warmer and may return to the point at which Greenland is again usable as farmland (as it has been in recorded history).

As the polar ice caps decrease, the amount of fresh water mixing with oceanic water will slow and perhaps stop the thermohaline cycle (the oceanic heat 'conveyor' which, among other things, keeps the U.S. east coast warm).

When this cycle slows/stops, the planet will cool again and begin to enter another ice age.

It's been happening for millions of years.

The worrisome and brutal predictions of drastic climate effects are based on computer models, NOT CLIMATE HISTORY.

As you probably know, computer models are not the most reliable of sources, especially when used to 'predict' chaotic systems such as weather.

Global warming/cooling, AKA 'climate change':

Humans did not cause it.

Humans cannot stop it.

Answer 3

I watched a special about that and some scientist believe that a massive volcano eruption or mild asteroid impact might have caused a very quick climate change.

The eruption of Mt El Chichon in 1982 caused the earth's temp to drop half a degree C for a year or two and that was a rather small eruption.

Just two large eruptions in a 1 year span could cause the earth's temp to drop upwards of 2-3C, which is enough to cause major climate change.  

Something like this could cause hundreds of millions to die today, but given the earth's population ( 6.65 billion) and our advancements in technology and ability to use it to adapt, there's no way we would be wiped out. You could kill off 5.65 billion people and still have 1 billion of us running around.

All in all, it's going to be VERY hard to get us humans off the planet.

Answer 4

Maybe.  But it doesn't mean TODAY'S changes are natural.

The data shows that previous climate changes were likely due to the Sun.  And that this one's not.

"Recent oppositely directed trends in solar

climate forcings and the global mean surface

air temperature", Lockwood and Frolich (2007), Proc. R. Soc. A

doi:10.1098/rspa.2007.1880

http://www.pubs.royalsoc.ac.uk/media/pro...

News article at:

http://news.bbc.co.uk/1/hi/uk/6290228.st...

The bottom line:

"We humans have built a remarkable socioeconomic system during perhaps the only time when it could be built, when climate was sufficiently stable to allow us to develop the agricultural infrastructure required to maintain an advanced society.  If the Earth came with an operating manual, the chapter on climate might begin with a caveat that the system has been adjusted at the factory for optimum comfort, so don't touch the dials."

Answer 5

Here's the article:

http://www.cnn.com/2008/TECH/04/24/close...

http://thescotsman.scotsman.com/latestne...

Tuba:  You are speaking about fossil records.  These theories are based upon mitochondrial DNA.  The human ancestral fossil record is in a constant state of debate/revision.  DNA is DNA.

The DNA points to all modern humans being descendants of a single woman who lived about 200,000 years ago.  The evidence also suggests we can all be subdivided into descendants of a handful of women dating back to around 70,000 years ago.  The two South African tribes studied exhibit DNA traits unique from the rest of the world's population.  Given the current understanding of historical human migration, coupled with mitochondrial DNA mapping, we can reasonably conclude early man separated into very small, isolated groups.  The theory is man was forced into these small groups due to a scarcity of resources and the inevitable battles over them.  Other explanations are possible without corroborating environmental evidence.

Edit:  This seems to coincide with the Wurm Glaciation (the last "Big" Ice Age, as opposed to the "Little Ice Age").

http://www.bartleby.com/67/18.html

hmmm....makes me think global warming good, global cooling bad.

Answer 6

I haven't read about this, but really... So what?!

You think that because a few survived that it was fine? I wonder what all the people that DIED thought of that little hiccup in our evolutionary existence.

And for that matter, if things got that close again, do you think you'd be one of the lucky ones to 'make it through' to keep the species going? Not unless you're one of those special few that we call multi-millionaires.

I don't know about you, but being alive means more than keeping the species going as far as I'm concerned. We need to encourage sustainability on a civilization level so we don't go anywhere NEAR only 1,000 breeding pairs again.

Wow, these arguments against trying to mitigate human induced climate change are getting weirder and weirder...

Answer 7

We almost got wiped out once by climate change but amazingly 2,000 of us survived... the conclusion is, then, that its alright to do it again, after all, 2,000 of us are going to survive, right?

A human race that is too stupid to learn the lesson the first time deserves to be wiped out!

Oh, and be careful with these sorts of facts - the number may have gone as low as 2,000 but what was the high? If it was 2010, then this wasn't a significant event...

That said, I know this story and yes, supposedly we went from a few million down to a few thousand but that was because we were vulnerable - low numbers in a relatively small percentage of the globe and with little capacity to adapt / react.

Answer 8

lolfggf

Answer 9

Climate Change did not almost wipe out humans 70,000 years ago....Chuck Norris did.  Enough said!