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Global Warming May Have Killed the Dinosaurs
The Fun Guy sent in a link to the American Society for Microbiology site, your leading news source for everything between nano and macro. The site is featuring a story about new research into the KT barrier extinction: the period in history where the dinosaurs went extinct, along with a number of other families of species. For a number of years scientists have theorized that an impact on the Yucatan peninsula was responsible for the species crash, but microbiological examination of marine organisms of the time indicate life persisted for another 300,000 years after the 'Chicxulub impact'. The researchers at Princeton who made this discovery theorize that global warming caused by a volcanic eruption in India is a more likely culprit for the world-wide devastation. The article generalizes that there is no 'smoking gun' for this event, and further research is required.
Ironically, the dinosaurs are playing a leading role in our own Global Warming Saga.
"You can't fight in here, this is the war room!"
The most plausible work I've seen on the subject is based on Durda & Kring's recent work on giant impacts and heat of re-entry. Based on the size of the Chixculub (sp?) impact crater, they concluded that the heat of re-entering rock on ballistic trajectories would have heated almost the entire atmosphere to incandescence. This is global warming of a sort, I suppose.
I've seen talks by archaeobiologists who assert that the dinosaurs were simply broiled by the heat coming from the atmosphere. That theory nicely explains why small, burrowing creatures suddenly took off and why the seas weren't as strongly affected by the land: anything small enough to hide in a burrow, or agile enough to swim deep underwater for a few days survived (at least in numbers large enough to propagate); everything else was cooked. It is also consistent with the fossil record, which shows huge amounts of charcoal cinders near the K-T boundary wherever you look, and a drastic change in the types of pollen present.
Disclaimer: I am not a paleontologist, I'm only an astrophysicist.
Obviously, the government needs to enforce reductions in volcanic emissions. In order to save our planet, we need to progress toward the use of more environmentally-friendly natural disasters.
"The findings suggest that global cooling led to a sea level drop from about 80 m to 30 m that apparently was more detrimental to foraminifera than was the Chicxulub impact, which occurred during the preceding warming." Maybe I'm missing something but I always thought the meteorite caused a lot of dust which obscured the sun and led to global cooling. That's what also happens with a volcano. So the Slashdot article says one thing but the article it cites says another. Hmm.
I know of at least one paper, published by Prof. Dewey McLean of Virginia Tech in the journal Science in 1978 that suggested that a major warming event was the cause of the K-T extinctions: "A terminal Mesozoic greenhouse: lessons from the past" (Science, 1978). Sometime later, he identified the Deccan Traps volcanism as a likely source of the CO2 that may have induced this warming: "Terminal Cretaceous Extinctions and Volcanism: a Link", in an abstract at the AAAS National Meeting, Toronto, Canada, in January 1981.
How do they explain away the layer of iridium rich clay (around the world) from around the time of the mass extinction. Current theory says it's vaporized impact material.
[Insert pithy quote here]
The Chicxulub event, while large, is not the only large impact suffered in Earth's history. There are quite a number of large craters in the geologic history, and probably more that we have not stumbled upon yet. The Earth Impact Database lists two craters larger than Chicxulub:
S ort2.htm
http://www.unb.ca/passc/ImpactDatabase/CIDiameter
Wikipedia blurbs on the two largest (as usual, do more research to verify if interested:)
http://en.wikipedia.org/wiki/Vredefort_crater
http://en.wikipedia.org/wiki/Sudbury_Basin
There are also questions about a possible crater in Antarctica, but it's too new an announcement to know if the features observed are actually impact related: http://researchnews.osu.edu/archive/erthboom.htm
My question is, why would the Chicxulub event have been so uniquely deadly?
I suppose one possible scenario is a double (or more) sucker punch of large impact followed by volcanic activity and/or other factors that happened to hit while the Earth was still recovering from the impact. Of course, that's a bit complex for a spectacular headline.
I hope work continues on this - it's a fascinating insight into our environment and might be useful in knowing how to safeguard ourselves against changes in the future.
"I object to doing things that computers can do." -- Olin Shivers, lispers.org
It's sad that there's a massive following of climate change deniers online. . .
.volcanos eruputing. For decades volcanoes have been well understood to cause global cooling by spreading ash into the high atmosphere which reflects solar radiation.
Look up, "The Year Without a Summer."
It was caused by . .
It's sad there's a massive following of the global warming is going to kill us all promoters online and off, to the extent that they've had to warp everything bad that happens, everytime, everywhere, to the effects of global warming.
Even ice ages fercrisakes.
No, I am not a global warming denier. 12,000 years ago Ireland was just emerging from under a sheet of glacial ice. Now there are palm trees in Kerry. Sea levels have risen about 400 feet. Things have clearly warmed up a bit. You'd have to be a kook to deny that. I'm a global climactic instability insistor. It's always, going up, or down; and sometimes even sideways (large, but local, changes. See the Sahara).
The climate will stop changing when the Sun expands and strips away the atmosphere; and not one minute before.
If this really bothers you go build yourself a biodome out beyond the Heliopause, but good luck controling its climate.
KFG
Nah. Everybody knows the real reason they died out.
For all intensive purposes, "whom" is no longer a word. That begs the question, "who cares"?
Every time one of these simple-minded "scientists" proclaims Chicxulub didn't do it, because of "X", it reminds me how badly science suffers from monomania.
It's really not that difficult: the Earth's climate has demonstrated multiple stable (more than a few million years) and metastable states, ranging from snowball to hothouse, with side trips through conditions like our current glacial/interglacial metastate. The rate at which climate state can change, once change begins, is generally faster than species, particularly those embedded in "eco-web", can follow. When the Chicxulub event happened, the global climate state was moved toward a different one which was not conducive to the major fauna of the time, the dinosaurs. It didn't kill everything overnight (except near ground zero), but may have thrown off the timing of mating, reduced the efficiency of some primary plant's life-cycle, or in some other way moved the birth rate of the dinosaurs to below replacement (less efficient animals have fewer reserves and are more vulnerable to disease, for example). Some species and ecosystems may have required a few hundred thousand years to dwindle away, but the impact triggered that particular extinction event. Other events, such as the Permian-Triassic extinction, are more likely to have been caused by vulcanism.
Volcanos cause short term cooling until the ash falls out. Many volcanos erupting together cause longer term warming owing to the higher CO2 concentration.
c ould-be-paid-for-by.html you may want to closely scutinize what
has influenced your opinion here.
s -selling-solar.html
You seem to want the climate to be entirely free from constraints of cause and effect, it can go wherever it wants for no reason at all. This is, I think, what you mean by instability. Climate feedbacks do occur but this is not the same thing as the butterfly effect which makes weather difficult to predict. Climate follows forcing and both the short term aerosols that you cite and the long term GHG balance have definite effects on climate.
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Because this false equating of weather behavior and climate behavior has been a major part of a well funded attempt to decieve the public http://mdsolar.blogspot.com/2007/01/your-opinion-
Skeptical about global warming? Who cares, you can still save money by switching to solar: http://mdsolar.blogspot.com/2007/01/slashdot-user
Well, that's the polite way of phrasing it. Basically they're just arrogant. They don't understand global warming (or evolution) and they really think that their own seat-of-the-pants assessment is more insightful than that of scientists who make their living analyzing the data. The virulent strain of populism that defines American culture encourages this. Evangelical Christianity encourages this. The media plays into it. The media exists to sell toothpaste and beer, and you don't sell as much toothpaste and beer if your message to viewers is "you don't understand things as well as you think you do, because you lack the education." It's a sad, self-perpetuating situation, but you (and all likeminded people) are stuck in a never-ending cycle of refuting the same claims, again and again and again and...
A professor of mine once pointed out something very interesting about the Indian volcano theory for the extinction of the dinosaurs. The Indian subcontinent was, 65 million years ago, more or less on the exact opposite side of the Earth from what would eventually become the Yucatan Peninsula. Remember that the Earth is really like a huge ball of liquid, molten rock (the mantle) with a thin crust of solidified material on the outside. What happens when you flick a water balloon really hard with your finger, but don't break it? The force of the blow causes waves to radiate throughout the water from the point of impact in all directions, and dissipates against the inside of the balloon. The point of strongest force for these waves will be on the direct opposite side of the balloon from the point of impact, which bubbles out briefly before returning to place.
On a global scale, a massive meteor impact would actually cause massive and very sudden volcanic eruptions on the opposite side of the Earth as it causes a wave of magma to concentrate on one very small spot.
Put those 4 things together and the "science" of climate change has a problem. The problem is simple: scientifically, we cannot use the scientific method to predict change because our best models are not yet scientifically predictive. That's an absolute problem, and it can't be fudged by wishful thinking.
We know many facts --- most of the measurements are not in doubt. The trouble is, we can't add those facts together because the underlying model isn't working even to first order. You HAVE to be able to model major effects like the glaciation cycle before you can be confident that your model is valid for smaller effects like a 1 or 2 degrees C of additional contributory greenhouse heating.
The fact that the vast majority of climatologists believe that we are witnessing unprecedented global warming and that man's outpouring of CO2 is the key factor in it really has no bearing on the above. Science is not about beliefs. And it's not about witnessing diverse effects in the world around us and mentally putting 2 and 2 together. That's not science.
The only thing that's really certain is that we're witnessing an unprecedented rise in CO2 levels, and that the extra CO2 is undoubtedly a contributing factor for any climate change. And that's it. That's all we know. The rest is supposition, and the results from our GCM simulations cannot be accepted as gospel because they are quite severely limited, and do not match history, and we know it.
I'm not actually a skeptic on global warming at all (personally), but I absolutely refuse to attribute to science a prediction that the scientific method cannot currently deliver. It's a matter of scientific integrity.
"The question of whether machines can think is no more interesting than [] whether submarines can swim" - Dijkstra
I'm a skeptic of anything so obviously incorrect, and much of the crud being presented as "research" by both the devotees and naysayers is definitely incorrect. The very little solid work is lost amidst the garbage.
That's why I'm skeptical about most of the claims being made by all the axe-grinders, be they doomsdayers or not.
Seriously, there's no money in everything being fine.
People who make money from oil, the Chinese, the Indians, and everyone else who wouldn't have to do any cleaning up would probably disagree with that statement.
There is bugger all money in anthropomorphic climate change. There is instead a big cost in changing things if it turns out to be true and therefore a big financial incentive to deny it at all costs.
That means you have to have millions and billions of cars to get any kind of a quantity.
Not to mention all the other vehicles including planes, trains, trucks etc and all factories pumping out waste. In any case there might well be a billion cars on the roads of the world now; if not it probably isn't that far off.
Given the recovery capacity of the planet, what makes you think your puny a$$ vespa or even my brontosaur vehicle can spew enough crap to cause climatic change?
What does the recovery capacity of the planet have to do with whether the human race gets wiped out or not?