songbird wrote:

a large portion of desertification is
from human activities like overgrazing
cows/sheep/goats and removing covering
forests for crops and firewood. some
areas the moisture in the forrests is
part of the local weather cycle. remove
the forrest, change the weather...

Humans have done a large but unknown about of that over the millennia.
The Sahara used to be grassland, as was most of central Asia. How much
was human grazing and farming and how much was natural climate change?
Very hard to tell after the fact.

in China they are trying to reforrest
some areas, but i'm not sure how much
success they've had. i don't think they
have enough moisture or organic stuff
planted along with the saplings so they
bake before they can grow. instead they
probably need an approach like the one
above that starts small and works up
to supporting trees one step at a time.

It would need to be done a step at a time. Getting grasses and shrub
bushes then building generation to generation.

In article ,
Doug Freyburger wrote:

songbird wrote:

a large portion of desertification is
from human activities like overgrazing
cows/sheep/goats and removing covering
forests for crops and firewood. some
areas the moisture in the forrests is
part of the local weather cycle. remove
the forrest, change the weather...

Humans have done a large but unknown about of that over the millennia.
The Sahara used to be grassland, as was most of central Asia. How much
was human grazing and farming and how much was natural climate change?
Very hard to tell after the fact.

What is "natural climate change"?

The graph on
http://en.wikipedia.org/wiki/Geologic_temperature_record#Recent_past
indicates that the planet was "naturally" getting cooler.

in China they are trying to reforrest
some areas, but i'm not sure how much
success they've had. i don't think they
have enough moisture or organic stuff
planted along with the saplings so they
bake before they can grow. instead they
probably need an approach like the one
above that starts small and works up
to supporting trees one step at a time.

It would need to be done a step at a time. Getting grasses and shrub
bushes then building generation to generation.
--
---------
http://www.youtube.com/watch?v=hYIC0eZYEtI
http://www.democracynow.org/blog/2011/3/7/michael_moore
http://www.youtube.com/watch?v=eZkDikRLQrw
http://www.youtube.com/watch?v=MyE5wjc4XOw

Billy wrote:
Doug Freyburger wrote:

The Sahara used to be grassland, as was most of central Asia. How much
was human grazing and farming and how much was natural climate change?
Very hard to tell after the fact.

What is "natural climate change"?

Change that is not caused by humans. There's been a lot of it in
geological time. Enough to ask if the human contribution in the current
trend is large or small. And that's independent of the real issue that
you point out in the graph - If global warming isn't really a good
thing.

The graph on
http://en.wikipedia.org/wiki/Geologic_temperature_record#Recent_past
indicates that the planet was "naturally" getting cooler.

The graph also shows that life in general has done very well during the
warmer geological periods. We're all doomed - The history of life
thriving during warm periods proves it! We're all doomed - Humanity
evolved during the recent swings and highs. Our prehistoric ancestors
have already been through several ice ages and warming periods. The
"we" part is specific parts of human culture not humanity in general
and not life in general.

Independent of the size of human contribution to global warming that's
the interesting point - Earth's life thrived under warming conditions.
Ancient humanity thrived under warming conditions. Therefore global
warming *must* be *entirely* human caused and we're all going to die
as a result of it! It's political BS at its finest. It ignores what has
actually happened during prior warm eras.

Even glancing at the graphs tells a different story. Life and humanity
have thrived under warmer conditions across geological time. Except for
folks living in Florida which will eventually be innundated, exactly how
again is life and humanity thriving a disaster? Last time I checked
there are planes, trains and automolbiles capable of evacuating Florida
in a lot less than the several centuries it will take for it to flood.
We'll need to replant the citrus groves elsewhere, completely
disasterous.

The degree of human contribution just doesn't matter in real terms -
Life in general and humanity in specific has thrived on Earth during
eras of warmer climate.

Is it bad just because it's different? Really? I look at those graphs
and I don't buy it. I look at those graphs and I wonder why I support
green energy sources like wind, solar and nuclear. Because fossil fuels
are limited resources, that's why.

In article ,
Doug Freyburger wrote:

Billy wrote:
Doug Freyburger wrote:

The Sahara used to be grassland, as was most of central Asia. How much
was human grazing and farming and how much was natural climate change?
Very hard to tell after the fact.

What is "natural climate change"?

Change that is not caused by humans. There's been a lot of it in
geological time. Enough to ask if the human contribution in the current
trend is large or small. And that's independent of the real issue that
you point out in the graph - If global warming isn't really a good
thing.

The graph on
http://en.wikipedia.org/wiki/Geologic_temperature_record#Recent_past
indicates that the planet was "naturally" getting cooler.

The graph also shows that life in general has done very well during the
warmer geological periods. We're all doomed - The history of life
thriving during warm periods proves it!
I realize that this is sarcasm, but let me point out the home, for Homo
sapiens is the Olduvai Gorge [Latitude: 2?59S], which is very near the
equator.
We're all doomed - Humanity
evolved during the recent swings and highs. Our prehistoric ancestors
have already been through several ice ages and warming periods. The
"we" part is specific parts of human culture not humanity in general
and not life in general.

Possibly.
--

http://www.sciam.com/article.cfm?cha...eID=00037A5 D
-A938-150E-A93883414B7F0000
October 2006 Scientific American Magazine

Impact from the Deep

Strangling heat and gases emanating from the earth and sea, not
asteroids, most likely caused several ancient mass extinctions. Could
the same killer-greenhouse conditions build once again?

By Peter D. Ward

Philosopher and historian Thomas S. Kuhn has suggested that scientific
disciplines act a lot like living organisms: instead of evolving slowly
but continuously, they enjoy long stretches of stability punctuated by
infrequent revolutions with the appearance of a new species--or in the
case of science, a new theory. This description is particularly apt for
my own area of study, the causes and consequences of mass extinctions --
those periodic biological upheavals when a large proportion of the
planet's living creatures died off and afterward nothing was ever the
same again.
(cont. below)


Independent of the size of human contribution to global warming that's
the interesting point - Earth's life thrived under warming conditions.
Ancient humanity thrived under warming conditions. Therefore global
warming *must* be *entirely* human caused and we're all going to die
as a result of it! It's political BS at its finest.

Granted, "political BS" is redundant.

It would help if you could separate the theatrics from your argument.

What is it that you offer as proof of your contention?

It ignores what has
actually happened during prior warm eras.

Even glancing at the graphs tells a different story. Life and humanity
have thrived under warmer conditions across geological time.

In the grand scheme of things, the few million years of humanoids
existence is hardly representative of the changing environmental
conditions on earth.
Except for
folks living in Florida which will eventually be innundated, exactly how
again is life and humanity thriving a disaster? Last time I checked
there are planes, trains and automolbiles capable of evacuating Florida
in a lot less than the several centuries it will take for it to flood.
We'll need to replant the citrus groves elsewhere, completely
disasterous.

The degree of human contribution just doesn't matter in real terms -
Life in general and humanity in specific has thrived on Earth during
eras of warmer climate.

Is it bad just because it's different? Really? I look at those graphs
and I don't buy it. I look at those graphs and I wonder why I support
green energy sources like wind, solar and nuclear. Because fossil fuels
are limited resources, that's why.

No concern over rising CO2 levels? Why not?

http://www.sciam.com/article.cfm?cha...eID=00037A5 D
-A938-150E-A93883414B7F0000

October 2006 Scientific American Magazine

(cont.)
Since first recognizing these historical mass extinctions more than two
centuries ago, paleontologists believed them to have been gradual
events, caused by some combination of climate change and biological
forces such as predation, competition and disease. But in 1980 the
understanding of mass extinctions underwent a Kuhnian revolution when a
team at the University of California, Berkeley, led by geologist Walter
Alvarez proposed that the famous dinosaur-killing extinction 65 million
years ago occurred swiftly, in the ecosystem catastrophe that followed
an asteroid collision. Over the ensuing two decades, the idea that a
bolide from space could smite a significant segment of life on the earth
was widely embraced--and many researchers eventually came to believe
that cosmic detritus probably caused at least three more of the five
largest mass extinctions. Public acceptance of the notion crystallized
with Hollywood blockbusters such as Deep Impact and Armageddon.

Now still another transformation in our thinking about life's punctuated
past is brewing. New geochemical evidence is coming from the bands of
stratified rock that delineate mass extinction events in the geologic
record, including the exciting discovery of chemical residues, called
organic biomarkers, produced by tiny life-forms that typically do not
leave fossils. Together these data make it clear that cataclysmic impact
as a cause of mass extinction was the exception, not the rule. In most
cases, the earth itself appears to have become life's worst enemy in a
previously unimagined way. And current human activities may be putting
the biosphere at risk once again.

After Alvarez
To understand the general enthusiasm for the impact paradigm, it helps
to review the evidence that fueled it. The scenario advanced by Alvarez,
along with his father, physicist Luis W. Alvarez, and nuclear chemists
Helen V. Michel and Frank Asaro, contained two separate hypotheses:
first, that a fairly large asteroid--estimated to have been 10
kilometers in diameter--struck the earth 65 million years ago; second,
that the environmental consequences of the impact snuffed out more than
half of all species. They had found traces left by the blow in a thick
layer of iridium--rare on the earth but common in extraterrestrial
materials--that had dusted the globe.

Within a decade of this prodigious announcement the killer's thumbprint
turned up, in the form of the Chicxulub crater hiding in plain sight on
the Yucatn Peninsula of Mexico. Its discovery swept aside most lingering
doubts about whether the reign of the dinosaurs had ended with a bang.
At the same time, it raised new questions about other mass extinction
events: If one was caused by impact, what about the rest? Five times in
the past 500 million years most of the world's life-forms have simply
ceased to exist. The first such event happened at the end of the
Ordovician period, some 443 million years ago. The second, 374 million
years ago, was near the close of the Devonian. The biggest of them all,
the Great Dying, at the end of the Permian 251 million years ago, wiped
out 90 percent of ocean dwellers and 70 percent of plants, animals, even
insects, on land [see "The Mother of Mass Extinctions," by Douglas H.
Erwin; Scientific American, July 1996]. Worldwide death happened again
201 million years ago, ending the Triassic period, and the last major
extinction, 65 million years ago, concluded the Cretaceous with the
aforementioned big bang.

The earth can, and probably did, exterminate its own.

In the early 1990s paleontologist David Raup's book Extinctions: Bad
Genes or Bad Luck? predicted that impacts ultimately would be found to
be the blame for all these major mass extinctions and other, less severe
events as well. Evidence for impact from the geologic boundary between
the Cretaceous and Tertiary (-K/T) periods certainly was and remains
convincing: in addition to the Chicxulub crater and the clear iridium
layer, impact debris, including pressure-shocked stone scattered across
the globe, attests to the blow. Further chemical clues in ancient
sediments document rapid changes in the world's atmospheric composition
and climate that soon followed.

For several other extinction periods, the signs also seemed to point
"up." Geologists had already associated a thin iridium layer with the
end Devonian extinctions in the early 1970s. And by 2002 separate
discoveries suggested impacts at the end Triassic and end Permian
boundaries. Faint traces of iridium registered in the Triassic layer.
And for the Permian, distinctive carbon "buckyball" molecules believed
to contain trapped extraterrestrial gases added another intriguing clue
[see "Repeated Blows," by Luann Becker; Scientific American, March
2002]. Thus, many scientists came to suspect that asteroids or comets
were the source of four of the "big five" mass extinctions; the
exception, the end Ordovician event, was judged the result of radiation
from a star exploding in our cosmic neighborhood.

As researchers continued to probe the data in recent years, however,
they found that some things did not add up. New fossil analyses
indicated that the Permian and Triassic extinctions were drawn-out
processes spanning hundreds of thousands of years. And newly obtained
evidence of the rise and fall of atmospheric carbon, known as carbon
cycling, also seemed to suggest that the biosphere suffered a
long-running series of environmental insults rather than a single,
catastrophic strike.

Not So Sudden Impact

The lesson of the K/T event was that a large-body impact is like a major
earthquake leveling a city: the disaster is sudden, devastating, but
short-lived--and after it is over, the city quickly begins rebuilding.
This tempo of destruction and subsequent recovery is reflected in
carbon-isotope data for the K/T extinctions as well as in the fossil
record, although verifying the latter took the scientific community some
time. The expected sudden die-off at the K/T boundary itself was indeed
visible among the smallest and most numerous fossils, those of the
calcareous and siliceous plankton, and in the spores of plants. But the
larger the fossils in a group, the more gradual their extinction looked.

Slowly, paleontologists came to understand that this apparent pattern
was influenced by the sparsity of large-fossil samples for most of the
soil and rock strata being studied. To address this sampling problem and
gain a clearer picture of the pace of extinction, Harvard University
paleontologist Charles Marshall developed a new statistical protocol for
analyzing ranges of fossils. By determining the probability that a
particular species has gone extinct within a given time period, this
analytical method teases out the maximum amount of information yielded
by even rare fossils.

In 1996 Marshall and I joined forces to test his system on K/T
stratigraphic sections and ultimately showed that what had appeared to
be a gradual extinction of the most abundant of the larger marine
animals, the ammonites (molluscan fossils related to the chambered
nautilus) in Europe, was instead consistent with their sudden
disappearance at the K/T boundary itself. But when several researchers,
including myself, applied the new methodology to earlier extinctions,
the results differed from the K/T sections. Studies by my group of
strata representing both marine and nonmarine environments during the
latest parts of the Permian and Triassic periods showed a more gradual
succession of extinctions clustered around the boundaries.

That pattern was also mirrored in the carbon-isotope record, which is
another powerful tool for understanding rates of extinction. Carbon
atoms come in three sizes, or isotopes, with slightly varying numbers of
neutrally charged particles in the nucleus. Many people are familiar
with one of these isotopes, carbon 14 (14C), because its decay is often
used to date specific fossil skeletons or samples of ancient sediments.
But for -interpreting mass extinctions, a more useful type of
information to extract from the geologic record is the ratio of 12C to
13C isotopes, which provides a broader snapshot of the vitality of plant
life at the time.

That is because photosynthesis largely drives changes in the 12C-13C
ratio. Plants use energy from the sun to split carbon dioxide (CO2) into
organic carbon, which they exploit to build cells and provide energy;
happily for us animals, free oxygen is their waste product. But plants
are finicky, and they preferentially choose CO2 containing 12C. Thus,
when plant life--whether in the form of photosynthesizing microbes,
floating algae or tall trees--is abundant, a higher proportion of CO2
remaining in the atmosphere contains 13C, and atmospheric 12C is
measurably lower.

By examining the isotope ratios in samples from before, during and after
a mass extinction, investigators can obtain a reliable indicator of the
amount of plant life both on land and in the sea. When researchers plot
such measurements for the K/T event on a graph, a simple pattern
emerges. Virtually simultaneously with the emplacement of the so-called
impact layer containing mineralogical evidence of debris, the carbon
isotopes shift--13C drops dramatically--for a short time, indicating a
sudden die-off of plant life and a quick recovery. This finding is
entirely consistent with the fossil record of both larger land plants
and the sea's microscopic plankton, which underwent staggering losses in
the K/T event but bounced back rapidly.

In contrast, the carbon records revealed by my group in early 2005 for
the Permian, and more recently for the Triassic, document a very
different fate for plants and plankton during those two mass
extinctions. In both cases, multiple isotope shifts over intervals
exceeding 50,000 to 100,000 years indicate that plant communities were
struck down, then re-formed, only to be perturbed again by a series of
extinction events. To produce such a pattern would take a succession of
asteroid strikes, thousands of years apart. But no mineralogical
evidence exists for a string of impacts during either time span.

Indeed, further investigation of the evidence has called into question
the likelihood of any impacts at those two times. No other research
groups have replicated the original finding of buckyballs containing
extraterrestrial gas at the end Permian boundary. A discovery of shocked
quartz from that period has also been recanted, and geologists cannot
agree whether purported impact craters from the event in the deep ocean
near Australia and under ice in Antarctica are actually craters or just
natural rock formations. For the end Triassic, the iridium found is in
such low concentrations that it might reflect a small asteroid impact,
but nothing of the planet-killing scale seen at the K/T boundary. If
impacts are not supported as the cause of these mass extinctions,
however, then what did trigger the great die-offs? A new type of
evidence reveals that the earth itself can, and probably did,
exterminate its own inhabitants.

Ghastly Greenhouse

About half a decade ago small groups of geologists began to team up with
organic chemists to study environmental conditions at critical times in
the earth's history. Their work involved extracting organic residues
from ancient strata in search of chemical "fossils" known as biomarkers.
Some organisms leave behind tough organic molecules that survive the
decay of their bodies and become entombed in sedimentary rocks. These
biomarkers can serve as evidence of long-dead life-forms that usually do
not leave any skeletal fossils. Various kinds of microbes, for example,
leave behind traces of the distinctive lipids present in their cell
membranes--traces that show up in new forms of mass spectrometry, a
technique that sorts molecules by mass.

This biomarker research was first conducted on rocks predating the
history of animals and plants, in part to determine when and under what
conditions life first emerged on the earth. But within the past few
years scientists began sampling the mass extinction boundaries. And to
the great surprise of those doing this work, data from the periods of
mass extinction, other than the K/T event, suggested that the world's
oceans have more than once reverted to the extremely low oxygen
conditions, known as anoxia, that were common before plants and animals
became abundant.

Among the biomarkers uncovered were the remains of large numbers of tiny
photosynthetic green sulfur bacteria. Today these microbes are found,
along with their cousins, photosynthetic purple sulfur bacteria, living
in anoxic marine environments such as the depths of stagnant lakes and
the Black Sea, and they are pretty noxious characters. For energy, they
oxidize hydrogen sulfide (H2S) gas, a poison to most other forms of
life, and convert it into sulfur. Thus, their abundance at the
extinction boundaries opened the way for a new interpretation of the
cause of mass extinctions.

Scientists have long known that oxygen levels were lower than today
around periods of mass extinction, although the reason was never
adequately identified. Large-scale volcanic activity, also associated
with most of the mass extinctions, could have raised CO2 levels in the
atmosphere, reducing oxygen and leading to intense global warming--long
an alternative theory to the impacts; however, the changes wrought by
volcanism could not necessarily explain the massive marine extinctions
of the end Permian. Nor could volcanoes account for plant deaths on
land, because vegetation would thrive on increased CO2 and could
probably survive the warming.

But the biomarkers in the oceanic sediments from the latest part of the
Permian, and from the latest Triassic rocks as well, yielded chemical
evidence of an ocean-wide bloom of the H2S-consuming bacteria. Because
these microbes can live only in an oxygen-free environment but need
sunlight for their photosynthesis, their presence in strata representing
shallow marine settings is itself a marker indicating that even the
surface of the oceans at the end of the Permian was without oxygen but
was enriched in H2S.

In today's oceans, oxygen is present in essentially equal concentrations
from top to bottom because it dissolves from the atmosphere into the
water and is carried downward by ocean circulation. Only under unusual
circumstances, such as those that exist in the Black Sea, do anoxic
conditions below the surface permit a wide variety of oxygen-hating
organisms to thrive in the water column. Those deep-dwelling anaerobic
microbes churn out copious amounts of hydrogen sulfide, which also
dissolves into the seawater. As its concentration builds, the H2S
diffuses upward, where it encounters oxygen diffusing downward. So long
as their balance remains undisturbed, the oxygenated and hydrogen
sulfide-saturated waters stay separated, and their interface, known as
the chemocline, is stable. Typically the green and purple sulfur
bacteria live in that chemocline, enjoying the supply of H2S from below
and sunlight from above.

Yet calculations by geoscientists Lee R. Kump and Michael A. Arthur of
Pennsylvania State University have shown that if oxygen levels drop in
the oceans, conditions begin to favor the deep-sea anaerobic bacteria,
which proliferate and produce greater amounts of hydrogen sulfide. In
their models, if the deepwater H2S concentrations were to increase
beyond a critical threshold during such an interval of oceanic anoxia,
then the chemocline separating the H2S-rich deepwater from oxygenated
surface water could have floated up to the top abruptly. The horrific
result would be great bubbles of toxic H2S gas erupting into the
atmosphere.

Their studies indicate that enough H2S was produced by such ocean
upwellings at the end of the Permian to cause extinctions both on land
and in the sea. And this strangling gas would not have been the only
killer. Models by Alexander Pavlov of the University of Arizona show
that the H2S would also have attacked the planet's ozone shield, an
atmospheric layer that protects life from the sun's ultraviolet (UV)
radiation. Evidence that such a disruption of the ozone layer did happen
at the end of the Permian exists in fossil spores from Greenland, which
display deformities known to result from extended exposure to high UV
levels. Today we can also see that underneath "holes" in the ozone
shield, especially in the Antarctic, the biomass of phytoplankton
rapidly decreases. And if the base of the food chain is destroyed, it is
not long until the organisms higher up are in desperate straits as well.

Kump and Arthur estimate that the amount of H2S gas entering the late
Permian atmosphere from the oceans was more than 2,000 times the small
amount given off by volcanoes today. Enough of the toxic gas would have
permeated the atmosphere to have killed both plants and
animals--particularly because the lethality of H2S increases with
temperature. And several large and small mass extinctions seem to have
occurred during short intervals of global warming. That is where the
ancient volcanic activity may have come in.

Around the time of multiple mass extinctions, major volcanic events are
known to have extruded thousands of square kilometers of lava onto the
land or the seafloor. A by-product of this tremendous volcanic
outpouring would have been enormous volumes of carbon dioxide and
methane entering the atmosphere, which would have caused rapid global
warming. During the latest Permian and Triassic as well as in the early
Jurassic, middle Cretaceous and late Paleocene, among other periods, the
carbon-isotope record confirms that CO2 concentrations skyrocketed
immediately before the start of the extinctions and then stayed high for
hundreds of thousands to a few million years.

But the most critical factor seems to have been the oceans. Heating
makes it harder for water to absorb oxygen from the atmosphere; thus, if
ancient volcanism raised CO2 and lowered the amount of oxygen in the
atmosphere, and global warming made it more difficult for the remaining
oxygen to penetrate the oceans, conditions would have become amenable
for the deep-sea anaerobic bacteria to generate massive upwellings of
H2S. Oxygen-breathing ocean life would have been hit first and hardest,
whereas the photosynthetic green and purple H2S-consuming bacteria would
have been able to thrive at the surface of the anoxic ocean. As the H2S
gas choked creatures on land and eroded the planet's protective shield,
virtually no form of life on the earth was safe.

Kump's hypothesis of planetary killing provides a link between marine
and terrestrial extinctions at the end of the Permian and explains how
volcanism and increased CO2 could have triggered both. It also resolves
strange findings of sulfur at all end Permian sites. A poisoned ocean
and atmosphere would account for the very slow recovery of life after
that mass extinction as well.

Finally, this proposed sequence of events pertains not only to the end
of the Permian. A minor extinction at the end of the Paleocene epoch 54
million years ago was already--presciently--attributed to an interval of
oceanic anoxia somehow triggered by short-term global warming.
Biomarkers and geologic evidence of anoxic oceans suggest that is also
what may have occurred at the end Triassic, middle Cretaceous and late
Devonian, making such extreme greenhouse-effect extinctions possibly a
recurring phenomenon in the earth's history.

Most troubling, however, is the question of whether our species has
anything to fear from this mechanism in the futu If it happened
before, could it happen again? Although estimates of the rates at which
carbon dioxide entered the atmosphere during each of the ancient
extinctions are still uncertain, the ultimate levels at which the mass
deaths took place are known. The so-called thermal extinction at the end
of the Paleocene began when atmospheric CO2 was just under 1,000 parts
per million (ppm). At the end of the Triassic, CO2 was just above 1,000
ppm. Today with CO2 around 385 ppm, it seems we are still safe. But with
atmospheric carbon climbing at an annual rate of 2 ppm and expected to
accelerate to 3 ppm, levels could approach 900 ppm by the end of the
next century, and conditions that bring about the beginnings of ocean
anoxia may be in place. How soon after that could there be a new
greenhouse extinction? That is something our society should never find
out.

ABOUT THE AUTHOR(S)
PETER D. WARD is a professor in the University of Washington's biology
department and its earth and space sciences division, where he
investigates both realms. His terrestrial research centers on ancient
mass extinction events as well as the evolution and ultimate extinction
of the nautiluslike marine animals known as ammonites, which he
described in his first article for Scientific American in October 1983.
Ward also applies principles gleaned from studying the earth's earliest
life-forms to research for the NASA Astrobiology Institute into
potential habitats for life elsewhere. He discussed those environments
in an October 2001 Scientific American article, "Refuges for Life in a
Hostile Universe," written with Guillermo Gonzalez and Donald Brownlee,
as well as in a popular book co-authored with Brownlee, Rare Earth: Why
Complex Life Is So Uncommon in the Universe (Springer, 2000).
--
---------
http://www.youtube.com/watch?v=hYIC0eZYEtI
http://www.democracynow.org/blog/2011/3/7/michael_moore
http://www.youtube.com/watch?v=eZkDikRLQrw
http://www.youtube.com/watch?v=MyE5wjc4XOw