"Global Warming, Not Asteroids Caused Planet's Mass Extinction Events" - Leading Climate-Change Experts

“If you look at the fossil record, it is just littered with dead bodies from past catastrophes,”  observes University of Washington paleontologist Peter Ward. Ward says that only one extinction in Earth’s past was caused by an asteroid impact – the event 65 million years ago that ended the age of the dinosaurs. All the rest, he claims, were caused by global warming.

“If you look at the fossil record, it is just littered with dead bodies from past catastrophes,”  observes University of Washington paleontologist Peter Ward. Ward says that only one extinction in Earth’s past was caused by an asteroid impact – the event 65 million years ago that ended the age of the dinosaurs. All the rest, he claims, were caused by global warming.

Ward's Under a Green Sky explores extinctions in Earth’s past and predicts extinctions to come in the future.

Ward demonstrates that the ancient past is not just of academic concern. Everyone has heard about how an asteroid did in the dinosaurs, and NASA and other agencies now track Near Earth objects. Unfortunately, we may not be protecting ourselves against the likeliest cause of our species' demise. Ward explains how those extinctions happened, and then applies those chilling lessons to the modern day: expect drought, superstorms, poison–belching oceans, mass extinction of much life, and sickly green skies.

The significant points Ward stresses are  geologically rapid climate change has been the underlying cause of most great "extinction" events. Those events have been, observed Harvard evolutionary biologist Stephen Gould, major drivers of evolution. Drastic climate change has not always been gradual; there is solid empirical evidence of catastrophic warming events taking place in centuries, perhaps even decades. The impact of atmospheric warming is most potent in its modification of ocean chemistry and of circulating currents; warming inevitably leads to non-mixing anoxic dead seas. We are already in the middle, not the beginning, of an anthropogenic global warming, caused by agriculture and deforestation, which began some 10,000 years ago but which is now accelerating exponentially; though the earliest wave of anthropogenic warming has been stabilizing and beneficial to human development, it appears to have the potential for catastrophic effects within a lifetime or two.

Looking at the ancient evidence, Ward notes that ice caps began to shrink. "Melting all the ice caps causes a 75-meter increase in sea level will remove every coastal city on our planet." It will also cover earth's most productive farmland, the author warns, adding, "It will happen if we do not somehow control CO2 rise in the atmosphere."

A new analysis of the geological record of the Earth's sea level, carried out by scientists at Princeton and Harvard universities supports Ward using a novel statistical approach that reveals the planet's polar ice sheets are vulnerable to large-scale melting even under moderate global warming scenarios. Such melting would lead to a large and relatively rapid rise in global sea level.

According to the analysis, an additional 2 degrees of global warming could commit the planet to 6 to 9 meters (20 to 30 feet) of long-term sea level rise. This rise would inundate low-lying coastal areas where hundreds of millions of people now reside. It would permanently submerge New Orleans and other parts of southern Louisiana, much of southern Florida and other parts of the U.S. East Coast, much of Bangladesh, and most of the Netherlands, unless unprecedented and expensive coastal protection were undertaken. And while the researchers' findings indicate that such a rise would likely take centuries to complete, if emissions of greenhouse gases are not abated, the planet could be committed during this century to a level of warming sufficient to trigger this outcome.

The last interglacial stage provides a historical analog for futures with a fairly moderate amount of warming; the high sea levels during the stage suggest that significant chunks of major ice sheets could disappear over a period of centuries in such futures.

Previous geological studies of sea level benchmarks such as coral reefs and beaches had shown that, at many localities, local sea levels during the last interglacial stage were higher than today. But local sea levels differ from those in this earlier stage; one major contributing factor is that the changing masses of the ice sheets alter the planet's gravitational field and deform the solid Earth. As a consequence, inferring global sea level from local geological sea level markers requires a geographically broad data set, a model of the physics of sea level, and a means to integrate the two. The study's authors provide all three, integrating the data and the physics with a statistical approach that allows them to assess the probability distribution of past global sea level and its rate of change.

The findings indicate that sea level during the last interglacial stage rose for centuries at least two to three times faster than the recent rate, and that both the Greenland and West Antarctic ice sheet likely shrank significantly and made important contributions to sea level rise. However, the relative timing of temperature change and sea level change during the last interglacial stage is fairly uncertain, so it is not possible to infer from the analysis how long an exposure to peak temperatures during this stage was needed to commit the planet to peak sea levels.

A similar study by a team of scientists from Bristol, Cardiff and Texas A&M universities braved the lions and hyenas of a small East African village to extract microfossils from rocks which have revealed the level of CO2 in the Earth’s atmosphere at the time of the formation of the ice-cap. New carbon dioxide data confirm that formation of the Antarctic ice-cap some 33.5 million years ago was due to declining carbon dioxide in the atmosphere.

Professor Paul Pearson from Cardiff University’s School of Earth and Ocean Sciences, who led the mission to the remote East Africa village of Stakishari said: “About 34 million years ago the Earth experienced a mysterious cooling trend. Glaciers and small ice sheets developed in Antarctica, sea levels fell and temperate forests began to displace tropical-type vegetation in many areas.

“The period culminated in the rapid development of a continental-scale ice sheet on Antarctica, which has been there ever since. We therefore set out to establish whether there was a substantial decline in atmospheric carbon dioxide levels as the Antarctic ice sheet began to grow.”

Co-author Dr Bridget Wade from Texas A&M University Department of Geology and Geophysics added: “This was the biggest climate switch since the extinction of the dinosaurs 65 million years ago. Our study is the first to provide a direct link between the establishment of an ice sheet on Antarctica and atmospheric carbon dioxide levels and therefore confirms the relationship between carbon dioxide levels in the atmosphere and global climate.”

Geologists have long speculated that the formation of the Antarctic ice-cap was caused by a gradually diminishing natural greenhouse effect. The study’s findings, published in Nature online, confirm that atmospheric CO2 started to decline about 34 million years ago, during the period known to geologists as the Eocene - Oligocene climate transition, and that the ice sheet began to form about 33.5 million years ago when CO2 in the atmosphere reached a tipping point of around 760 parts per million.

The team mapped large expanses of bush and wilderness and pieced together the underlying local rock formations using occasional outcrops of rocks and stream beds. Eventually they discovered sediments of the right age near a traditional African village called Stakishari. By assembling a drilling rig and extracting hundreds of meters of samples from under the ground they were able to obtain exactly the piece of Earth's history they had been searching for.

Ward is encouraged that we are beginning to make changes in their daily lives and demanding action from their leaders -"that we are on a planet that has violent convulsions, and that we humans are playing with nature in such a way that we could recreate what were some really awful times in earth's history, that we really tinker with the earth's atmosphere at our peril."

Posted by Casey Kazan from material provided by Princeton University and Bristol University

http://www.bris.ac.uk/news/2009/6546.html

Comments

[Vacation Packages]

Harvard universities supports Ward using a novel statistical approach that reveals the planet's polar ice sheets

[Bob]

- I.Velikovsky, Worlds in Collision (3600 years ago): "Two celestial bodies have been attracted one to each other. The inner masses of the Earth were pushed to the periphery. The Earth with its rotation movement disturbed, started towarm…The Earth exploded and the lava started to spread around"...
- Associated Press about 3,600 Years Ago Natural Disasters...
- ECOLOGICAL EVIDENCE FROM PREVIOUS PLANET X PASSAGES:
http://cristiannegureanu.blogspot.com/2010/01/lost-city-of-atlantis-could-be-buried.html

[Fred]

Not so fast...

http://www.guardian.co.uk/environment/2010/feb/21/sea-level-geoscience-retract-siddall

[Tom]

No, no. Its population explosion of the dominate species causes climate change on global scale that causes mass extinction.

[CF]

this is the dumbest shit I have read here yet

[Madhy Pradesh]

Geologists have long speculated that the formation of the Antarctic ice-cap was caused by a gradually diminishing natural greenhouse effect.

[ham]

really?....you gotta be shitting me....

[Rob]

ell the do all seem to be found in mud pits or places that used to be wet a lot...

[Movies]

We all saw The Land Before Time. If we don't stop this there will be dinosaur species segregation and Little Foot will lose his tree star. And what will become of Petri!?! Won't someone please think of Petri!?!

[online]

Just a guess, but I suspect that past mass extinctions were caused by global cooling as often as global warming. Both would result in massive habitat changes.

[Me!]

Keep trying! Maybe someday one of the 150 variant stories of global warming and their derivative yarns might be believable. What's next? Blame dinosaur deaths on previous administrations?

[Jess WOods]

I disagree, it was either an asteroid OR a super volcano that caused the last mass extinction.

Jess
www.complete-anonymity.cz.tc

[Deeg]

Do you expect people to fall for this?

[Jim]

Go on and say it: it's all the Bush Administration's fault.

According to Danny Glover, -you know, the Lethal Weapon actor- the Haiti EARTHQUAKE was caused by global warming.

Seriously, this is all caused by the fact that Krypton is simply changing its orbit...

GDINY

[Jay]

Thank goodness this will now be impossible, thanks to the Utah Legislature which just passed a referendum stating that global warming is not true!

Up next, republicans pass bill to claim sun revolves around earth.

[Jay]

Thank goodness this will now be impossible, thanks to the Utah Legislature which just passed a referendum stating that global warming is not true!

Up next, republicans pass bill to claim sun revolves around earth.

[fred]

OO!! I got one!

Alain's came 40 billion light years across the galaxy and noticed that the earth was being taken over by these reptiles, so they set off huge mega-tun explosives off on both north and south poles which cause a very similar effect as global warming.. sorry "climate change", to reset the flow of things. With out the reptiles to eat us those of us who survived were free to thrive on this young planet.. at that time.

[Fred]

The simple fact of the matter is global warming has more than enough scientific evidence to back it. And the majority of the legitimist scientific community stands behind it.

But if a single right wing nut job politician says it is not so his lunatic followers will jump right on board. Let me see who we should believe, the guy with the educational background and no motive to say one way or another? Or should we believe the republican politician whose career was built on taking money from companies that benefit on global warming going away. Not to mention most of them are lucky they graduated from high school and I think most of the republican voters fall in the same category. As CNN showed during the last election most college grads are more likely to vote Democrat and not right wing nut job. I am also certain if a right wing goofball politician said the world was flat and it was a democratic conspiracy to prove it was round most of these same people would believe it.

[Tim]

I notice that all of the previous comments fail to address any of the arguments made, but simply indulge in snide ironical quips. Apparently, these people already know the answers to these issues, and don't need to bother with careful consideration and rebuttal.

The gist: I don't need to be a scientists who carefully considers the evidence to know whether global warming is real. A bit of a sneer and unearned self-confidence is enough.

[DarthVain]

Environmental changes forces species that fail to adapt to them to go extinct.

News at 11.

I am pretty sure every ice age caused a lot of extinctions as well. Any adverse fluctuation of temperature or environmental condition will have impact more or less depending on the severity of the change (both in degree and speed), and the ability or rather the inability of certain species to adapt to those changes.

I mean surely this is common sense and not some revelation? Oh wait it has "Global Warming/Climate Change" in the title! Oh Noes we all gonna die!

Give me a break.

[Nicole]

Why do normal people think they know more than scientists?
It amazes me.
Obviously they have more evidence to back up their claims than anyone who comments here. -_-

[Philippine Real Estate Owner]

So what caused the Global warming long time ago?

Is it not human activity that causes global warming today? I am confused because if there are natural ways for global warming to take place at a time were SUVs and factories do not exist yet, then global warming can indeed happen again today even if there were no human intervention on what so ever.

[Robert Burt]

When the temperature in New York is 125 degrees, there will be no doubters.

[GDINY]

I will question the global warming/climate change THEORY as long as the self-appointed evangelists of the environment -i.e. Al Gore, the Kennedys- continue to generate more carbon emissions than I do with their use of private jets, limos, and oversized mansions.

[brothermartin]

a question...the story says "when CO2 in the atmosphere reached a tipping point of around 760 parts per million." the Antarctic ice sheet began to form...was that a misprint? (I do note the occasional typo in these pages)

If it wasn't a misprint, I gather that the CO2 in the atmosphere was declining when it passed that threshold, nearly twice the current level, and so it might take that much of a rise to totally melt the Antarctic?

Ah, insatiable curiosity....
thanks
non illegitimi carborundum!
mh