A universe of beauty, mystery and wonder

A universe of beauty, mystery and wonder

Tuesday, March 25, 2014


To begin with this debate seems to lack enough scientific spirit, since for too many scientists global warming - also referred to by the euphemism "climate change" - has developed the sacredness of religious dogma. 

Proselytising for climate change is the real agenda for many of these scientists. 
Climate by its very nature "changes" - but it's not the kind of threat that the scientific priesthood claims it to be.  Life has recovered from major climatic disasters in the ancient past.
Humans, however, are indeed the most serious AND IMMEDIATE threat to life that this planet has ever known, particularly since the inception of the nuclear age. 
The report below outlines the main arguments:  did humans caused megafauna to go extinct - or didn't they?  
The questions are mostly academic because regardless of the answer, the most urgent threats RIGHT NOW are the chemical, biological, genetic, and nuclear weapons humans have unleashed on the planet. 

Those weapons have negatively altered or already destroyed life forms and their habitat.

AND GREED is a big player too.  The fate of the elephant, among many other species, is an example of how mindless greed can wipe out a valuable species in only a few years.  Elephants are headed for extinction in only ten years.
Looking at a prehistoric human armed with spears as indicative of a trend and trying to apply that scenario to the present is quite absurd.
Humans had a lot to do with past animal extinctions.  How much, we really don't know.   
But what these scientists ought to be doing right now is fighting nuclear power that is threatening to wipe out all life on Earth.  
The damaged Fukushima nuclear power plant in Japan is expected to continue spewing tons of highly radioactive waste into the ocean for hundreds of years to come. 
And Fukushima is only one of many nuclear plants where a single human error or a natural disaster can turn them  into weapons of mass destruction in only a matter of minutes.  

But that's not all.  We are also leaving a legacy of nuclear waste for future generations.  We have literally turned paradise into a nuclear waste dump.
Endangered SIBERIAN TIGER - only 8000 left in the world, victims of poaching and human-caused damage to their habitat. 
ELEPHANTS too are endangered and it is estimated that at the current rate of poaching they will be extinct in only TEN YEARS.  The greatest consumers of elephant ivory are China and other Asian countries.


DAILY MAIL - Are humans Earth’s biggest enemy? Debate over whether we have destroyed the planet since mankind's birth rages at conference

  • The Megafauna conference took place in Oxford last week
  • Experts discussed the demise of large beasts across the world
  • They debated the impact climate change and humans had on these animals
  • Scientists are using a range of methods including radiocarbon dating, climate mapping and more to establish what led to the extinction
Mammoth - Royal British Columbia Museum

The Earth was once populated with enormous beasts, the likes of which we have never seen – from mammoths to giant beavers, and sabre-tooth tigers to horned tortoises.  

Over the last two million years many of these giant beasts, known as megafauna, have either been wiped out completely, or replaced by smaller counterparts living side-by-side with an ever increasing human population. 
The debate on exactly what caused this mass extinction has been raging for years – on one side of the fence, the demise is being blamed on natural climate change, on the other, humans and our carnivorous ways have ‘destroyed’ the world.

Earlier this week, St John’s College in Oxford played host to the annual Megafauna conference.   The meeting is a chance for experts, zoologists, archaeologists and scientists to debate the demise of these mega beasts and how their disappearance has impacted on how we live today.  
British environmentalist and writer George Monbiot is outspoken in his belief that humans are to blame for the mass extinction, a theory known as ‘overkill hypothesis.’  He believes there is a direct correlation between humans arriving and populating continents across the globe and the widely-seen demise of many megafauna species.   ‘Before Homo erectus, perhaps our first recognisably-human ancestor, emerged in Africa, the continent abounded with monsters.  'There were several species of elephants. There were sabretooths tigers and giant hyenas,’ said Monbiot.
He continued that while most people believe the beginning of the Anthropocene - the period in which we live and impact the world - began during the industrial revolution, Monbiot believes it started much earlier ‘with a killing spree that commenced two million years ago.  ‘What rose onto its hindlegs on the African savannahs was, from the outset, death: the destroyer of worlds.’ 
Aside from the correlation between the arrival of humans, and the ultimate demise of megafauna, Monbiot claimed ‘Homo erectus possessed several traits that appear to have made it invincible: intelligence, cooperation; an ability to switch to almost any food when times were tough; and a throwing arm that allowed it to do something no other species has ever managed - to fight from a distance.’  He added this ‘could have driven giant predators off their prey and harried monstrous herbivores to exhaustion and death.’
However, a study published in January stated otherwise. Researchers from Columbia found evidence that it wasn’t humans that wiped out these species and that instead the extinctions were a direct result of changes in climate. 
Archaeologists have been challenging the overkill hypothesis for years.  For example, some researchers argue that of the 36 species know to have become extinct, only two, namely the mammoth and the mastodon, exhibited signs of being hunted, including cuts on their bones and bodies. 
Other researchers have noticed correlations between when these animals became extinct, and significant changes in temperature as the last ice age ended.
To study these theories, archaeologists Matthew Boulanger and R. Lee Lyman of the University of Missouri, Columbia, studied the movement of megafauna in northeast of North America.  They used radiocarbon dating taken from samples of megafaunal fossils, and Paleoindian sites in the region, to establish that most of the megafauna had already disappeared before humans arrived - strongly suggesting humans had little to do with their extinctions.  
They also discovered that there were two so-called megafauna crashes in the region.   One approximately 14,100 years ago, before humans arrived in the region, and another 12,700 years ago, when Paleoindians arrived in the region.   After the first crash, population numbers increased 500 years later. 
They found that humans and megafauna lived side-by-side for almost 1,000 years before the animals finally went extinct, however, their numbers were already on the decline.   For example, up to 90 per cent of the northeastern megafauna were gone before humans arrived, and during the period of co-existence, the researchers found no evidence in the bones that these creatures were hunted by humans. 

Equally, the second crash corresponded with the start the Younger Dryas, a cold period which was followed by the warmer Holocene period we live in today.  This led the authors to conclude that climate was predominantly responsible for the mass extinction, and although their findings only applied to the northeastern area of North America, it is likely the trend was seen elsewhere. 
But Monbiot still isn't convinced: ‘I have never seen a paper demolished as elegantly and decisively as this was at last week’s conference.   ‘Archaeologists have demonstrated the mismatch is just what you would expect if humans were responsible,’ he continued.  ‘Mass destruction is easy to detect in the fossil record: in one layer, bones are everywhere, in the next they are nowhere. But people living at low densities with basic technologies leave almost no traces. 
‘With the human growth rates and kill rates you’d expect in the first pulse of settlement - about 14,000 years ago -, the great beasts would have lasted only 1,000 years.’
Other speakers were more a fan of the combined theory, that both climate and humans played a role - but to varying extents.  
Lewis Bartlett from the University of Exeter divided the world into 14 different zones ranging from South America, down to Tasmania and New Zealand.   He mapped megafaunal richness over 80,000 years and plotted the animals extinction. On top of this he mapped climate changes and human arrival.  ‘We built hundreds and hundreds of subsets of that data by randomly sampling all the ranges throughout that megafauna could have gone extinct in, and this way we can very explicitly deal with the uncertainty attached.’ 
Bartlett and his team randomly sampled hundreds of samples to create different data sets, and ran hundreds of models on all of these datasets so they could check the level of uncertainty.  In small islands they saw a sharp rise in extinction, before it tapered off.  But on a subcontinent level, they saw a much more prolonged and elevated period of extinction that didn’t have the spike after colonisation seen in the smaller regions.  Roughly a quarter to a third of extinctions in his model were found to be uniquely caused by climate change.

However, ‘a far greater proportion were uniquely ascribable by our human data and according to our models - humans are the main contributing factor.’  A ‘moderate’ range can then be explained by a combination of climate or humans. 

In Europe, given the size of the continent, the researchers saw an elevated rise in extinction levels in the 20,000 years after humans arrived. After that, they spotted another extinction spike, this time caused by climate. 
In the archipelagos, such as Tasmania, New Zealand and Madagascar, there was only one cause - humans. He said the arrival of humans explained ‘almost all’ of the extinctions. 
To summarise, Bartlett said: ‘Our work strongly implicates humans, as part of this extinction debate, and I think using this global analysis, we’ve demonstrated that humans can’t be dismissed as major contributors to this extinction debate.’
‘Similarly, climate is a strong indicative factor, but a caveat to that is that if we undertook this sort of analysis where climate is ubiquitous in any ecological system, we’d expect it to have an effect.  Any studies that found no link would make me sceptical.’
‘What we can take away is the relative importance of humans, and the stark realisation is that humans contribute far, far more to our ability to predict where these extinctions occur, than climate does, even though they are both informative.’
Professor Adrian Lister from the Natural History Museum added that the reason for the disappearance is ‘because large animals in Africa and south-east Asia learned to become wary of humans and decided to avoid them at all costs.  He continued: ‘However, I also think climate change may have been involved in the Americas and Australia and that humans only finished off these big animals when they were already weakened by loss of habitats and other climate-related problems.’
Professor Lister has been working on this topic for the past 10 years using radiocarbon dating. Although he has studied a range of animals, his talk at the conference concentrated on the demise of the woolly mammoth.   His research is being used as part of the museum's upcoming event Mammoths: Ice Age Giants, which opens on 23 May.
In a similar way to the researchers from Columbia, Professor Lister found that the global range of the woolly mammoth contracted and expanded in line with changes in temperature.   ‘If we put all that together, we have very strong evidence that changes in climate and vegetation did shift and ultimately contract the range of the woolly mammoth between 14,000 and 4,000 years ago, when the mammoth became extinct.  
‘There are shifts and contractions that link with changes in vegetation, and although it’s very difficult to establish population structure, it seems to be quite plausible.  We may consider this tremendous contraction of the mammoth range is plausibly driven by changes in vegetation and climate - but there was also the potential factor of humans adding into the mix, perhaps hitting those last remaining populations.  

'However, I don’t see anywhere in these data, evidence of something the humans were doing, and certainly not the distributional density of humans, that is responsible for the disappearance of mammoths at this point.  This evacuation is climate driven, unless people were suddenly hunting mammoths at a much greater degree.   Archaeological data suggests that during this time, people were very much eating horses and cattle – not megafauna. I don’t see in this data that the disappearance of mammoths in Europe at this time had anything to do with people. ‘

Original article with additional pictures of megafauna


Early humans wiped out giant elephants and other megafauna

Behind the romanticizing of primitive man
News on Fukushima
In the news:  Recurrent radiation leaks from nuclear waste dump at Carlsbad California

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