Dinosaurs were wiped off the face of the Earth by a sudden drop in temperature and not by a comet striking the planet, scientists claimed today.
Researchers studying fossils in Norway have discovered that the world's seas plummeted 9C from 13C to just 4C around 137 million years ago.
They believe this was caused by a sudden change in the Atlantic Gulf Stream - a phenomenon many experts fear is about to happen again.
The temperature drop during the Cretaceous period would almost certainly have wiped out an 'abundance' of the world's dinosaurs.
The scientists behind the ground-breaking study claim this would have been the first major step dinosaurs took on their eventual road to extinction.Some experts believe the creatures were wiped out by one cataclysmic event 65million years ago - such as a meteor hitting the planet.
But the new research suggests they were wiped out by a series of environmental changes - starting with a drop in sea temperatures.
The study was conducted by a team of scientists, led by Dr Gregory Price of Plymouth University, who examined fossils and minerals from Arctic Svalbard in Norway.
Dr Price found the drop in temperatures was so severe that numerous species of dinosaur previously living in warm, shallow seas, land and swamps would have died out.
He said the team's research showed the drop in temperature happened when the Earth was in a 'greenhouse' climate - similar to now.
'The drop in temperatures may well have been caused by a change in ocean circulation, much like what is being predicted for the Gulf Stream,' he said.
'In the Cretaceous period, the Atlantic was much narrower but it would have featured a similar, northerly-flowing current.
'If it had stopped working it could have resulted in the melting of the ice caps, causing a sudden drop in temperatures.
'We believe dinosaurs were most likely to be cold-blooded creatures and would have needed the warmth to keep them alive. If they were unable to migrate south they could have been wiped out.
'Climate change is now very much on the agenda in trying to determine how the dinosaurs became extinct.
'We now believe that they died out gradually and it is very possible that this could have been caused by a series of climatic changes.'
The drop in temperature is thought to have occurred because high levels of CO2 were in the atmosphere which caused global temperatures to rise and polar ice to melt - a phenomenon currently predicted for Earth.
It is the equivalent of the predicted shut-down of the Gulf Stream 'conveyor belt' - which scientists have warned could take Europe into another ice age.
Dr Price has been visiting the Svalbard since 2005, collecting fossils and samples in an area famed for a number of palaeontological discoveries, including giant marine reptiles such as pliosaurs and icthyosaurs.
He added: 'The flourishing of the dinosaurs and a range of other data indicates that the Cretaceous period was considerably warmer and boasted a high degree of CO2 in the atmosphere.
'But over a period of a few hundred or a few thousand years, ocean temperatures fell from an average of 13 degrees centigrade to between eight and four degrees.'via Dinosaurs killed off by sudden drop in temperature | Mail Online.
Side note: Volcanoes are not the cause of global warming and they don't put out more CO2 than humans:
Measurements of CO2 levels over the past 50 years do not show any significant rises after eruptions. Total emissions from volcanoes on land are estimated to average just 0.3 Gt of CO2 each year - about a hundredth of human emissions (pdf document).
This is going to baffle some folks. We are heating up the planet, and therefore, we may all freeze to death. Wha? Yes, you heard correctly. The price for our lack of understanding may be our near or total extinction. (Alternately, enough of us have to "get it" to take meaningful action, if we even can.
The earth is a very big dynamic system that responds to changes. We put more CO2 into the air and this greenhouse gas warms the surface. This causes ice to melt. The cold melted water from melting cracking ice shelves runs to the sea. Since sea temperature differences drive the gulf stream, the new cold water could shut the system down. This would bring about a rapid planet wide change in temperature according to the theory.
Yes, the earth did have climate change before us. Yes, this time, we are to blame. But I agree with the global warming deniers on one thing: Even if we do everything right, even if we reverse 100% man made global warming, one of the past causes of global climate change could still hit us.
Will we cook or freeze? Will it all balance out leaving us with a few thousand more years of good times like the present? Time will tell.
2 comments:
Before you go there: "We put more CO2 into the air" causing an increase in the Green House effect. Right?
Normally, the oceans take care of the CO2. Right?
That is, the plankton in the ocean that converts CO2 to oxygen. Plankton in all the world's oceans together produce about 70% of the oxygen in the atmosphere (the other 30% of whatever percent is atmospheric oxygen - 20%? -is produced by land plants etc.). But, the oceans are in trouble: the Great Garbage Patch (two in the Pacific - one has a diameter of 1000 km - and trash is piling up in other places also) and Dead Zones (the one in the Gulf of Mexico is the largest in the world during the summer).
So, in one way the plankton is getting all the CO2 it could use, but in another we're killing off the plankton or, at least interfering with it. (It's worse than that. The most of the trash in the ocean are plastics. And, plastics breakdown over long periods of time to smaller bits, which are consumed eventually by Plankton. And, plastic has a tendency, because it is an organic compound, to absorb organic toxins. So, what we have today are tiny toxic pellets - from the mfg process - and tiny fragments of plastics all over the earth's oceans, not just the Pacific, killing off or at least poisoning all sorts of critters.)
Thus, over time our atmosphere will not only have increasing amounts of CO2 but also decreasing amounts O2 as well - in worse possible future scenarios. Right?
Ha! It's funny how JUST A WHILE AGO they had a consensus stating it was a comet or an asteroid. :)
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