2016-10-10. Simulating the Climate 145 Million Years Ago.
By Shannon Hall, Earth and Space Science News (EoS, AGU).
2015-01-15. Tiny plant fossils offer window into Earth's landscape millions of years ago.
NSF Press Release 15-003.
2014-02-20. Seeking a Break in a 252 Million-Year-Old Mass Killing. A Geologist Investigates a Mass Extinction at the End of the Permian Period. Excerpt: Sam Bowring ... a geologist at M.I.T. ... wants to understand how an estimated 96 percent of all species on Earth became extinct at the end of the Permian Period 252 million years ago...the biggest of the five mass extinctions recorded in the fossil record. ...Dr. Bowring and his colleagues have ... made the most precise measurement yet of how long it took for all those species to become extinct...less than about 60,000 years. That’s a geological blink of an eye — a fact that will help scientists evaluate different hypotheses for what triggered the mass extinction. ...Studies on the rocks that formed around the time of the mass extinction ... revealed that ...Huge volcanoes in Siberia belched molten rock that covered millions of square miles. The oceans warmed dramatically, climbing 18 degrees Fahrenheit. ...the carbon in the rocks that formed around the time of the mass extinction...have a drastically higher ratio of light-to-heavy carbon. One way to create such a planet-wide shift would be to deliver a huge surge of carbon dioxide into the ocean. ...The volcanoes may well be the cause, but scientists have yet to establish all the links from eruptions to extinctions. ...the Siberian eruptions lasted for one to two million years. But the world’s biodiversity did not decline over a similar time scale. Instead, it swiftly collapsed with little advance warning.... http://www.nytimes.com/2014/02/21/science/earth/Mass-Extinction-Permian-Period.html. Carl Zimmer, The New York Times.
2013-10-08. When CO2 Levels Doubled 55 Million Years Ago, Earth May Have Warmed 9°F In 13 Years. Excerpt: The Paleocene/Eocene thermal maximum (PETM) and associated carbon pulse “are often touted as the best geologic analog for the current” manmade rise in CO2 levels, as a new study notes. The Proceedings of the National Academy of Sciences paper, “Evidence for a rapid release of carbon at the Paleocene-Eocene thermal maximum,” ...Rutgers geologists Morgan Schaller and James Wright argue that: … following a doubling in carbon dioxide levels, the surface of the ocean turned acidic over a period of weeks or months and global temperatures rose by 5 degrees centigrade – all in the space of about 13 years. Scientists previously thought this process happened over 10,000 years. ...Note that if we stay anywhere near our current emissions path, we are headed for a tripling or quadrupling of CO2 concentrations from preindustrial levels. ...the “dean of climate scientists,” Wallace Broecker who popularized the term “global warming” ...decades ago... said, “The climate system is an angry beast, and we are poking at it with sticks.” ...“My point [with the 'angry beast' metaphor] was that by adding large amounts of CO2 to the atmosphere, we were poking our climate system without being sure how it would respond,” he says. At the rate we are spewing carbon pollution into the atmosphere, one might even say we are punching the climate beast in the nose. Paleoclimate studies, including this new one, suggests that is a very, very bad move.... http://thinkprogress.org/climate/2013/10/08/2750191/petm-co2-levels-doubled-55-million-years-ago-global-temperatures-jumped/. Joe Romm, ThinkProgress.
2012-12-09. 5 million-year hangover | By Spencer Hunt, The Columbus Dispatch. Excerpt: Scientists say climate change slowed recovery after the world’s greatest extinction event 250 million years ago. …250 million years ago during a time that scientists call the Great Dying … world’s greatest extinction event wiped out 90 percent of life in the oceans and about 70 percent on land. Earth did recover, but it took about 5 million years, according to a team of earth scientists, including Ohio State University geologist Matthew Saltzman. “That’s a relatively long amount of time,” he said. “We see mass extinctions throughout Earth’s history and, in most cases, the recovery took place in about 1 million years or so.” …the mass extinction was triggered by a series of severe volcanic eruptions in a region called the Siberian Traps. After 1 million years of heavy volcanic activity, an area larger than Europe was covered in a layer of once-molten igneous rock 1 mile to 3 miles thick…. Researchers theorize that magma from the initial eruptions burned through an ancient coal bed. …Thomas Algeo, a University of Cincinnati geologist, said huge amounts of carbon dioxide and methane were released, killing off most remaining species. …After the Great Dying, increases in global temperatures made life nearly impossible for plants and animals on land and heated the oceans to an average 100 degrees Fahrenheit. …Saltzman said the Great Dying offers a window on the effects of climate change. He and Algeo cautioned that the current predictions for climate change are far from the global catastrophe that occurred 250 million years ago. …the average temperature increase then was two to three times higher than the increase climatologists are forecasting. Still, Saltzman said reactions to climate change can be severe…. Read the full article: http://www.dispatch.com/content/stories/science/2012/12/09/5-million-year-hangover.html
2012-09-10. Earlier Mass Extinction for Most of Marine Life | by Sindya Bhanoo, New York Times. Excerpt: Most scientists agree that dinosaurs became extinct as a result of a catastrophic meteor strike 65 million years ago near the Yucatán Peninsula. …But now scientists are suggesting that another mass extinction event occurred about 200,000 years earlier: a volcanic eruption on the Deccan Plateau of India. The eruption filled the atmosphere with aerosols — fine particles suspended in greenhouse gases that led to warming and, eventually, the extinction of much of marine life, especially shelled invertebrates on the ocean floor….. Read the full article: http://www.nytimes.com/2012/09/11/science/volcanic-eruption-may-have-caused-marine-life-extinction.html?ref=science
2010 April 9. Scientists Explore Origins of 'Supervolcanoes' on the
Sea Floor. National Science Foundation Update. Excerpt: "Supervolcanoes" have been blamed for
multiple mass extinctions in Earth's history, but the cause of their
massive eruptions is unknown. ..."'Supervolcanoes' emitted large amounts
of gases and particles into the atmosphere, and re-paved the ocean
floor," says Rodey Batiza, marine geosciences section head in the
National Science Foundation (NSF)'s Division of Ocean Sciences, which
co-funded the research. The result? "Loss of species, increased
greenhouse gases in the atmosphere, and changes in ocean circulation,"
says Batiza. In fall 2009, an international team of scientists
participating in IODP Expedition 324 drilled five sites in the ocean
floor. They studied the origin of the 145 million-year-old Shatsky Rise
volcanic mountain chain... 1,500 kilometers (930 miles) east of Japan,
... roughly the size of California... one of the largest supervolcanoes
in the world: the top of Shatsky Rise lies three and a half kilometers
(about two miles) below the sea's surface, while its base plunges to
nearly six kilometers (four miles) beneath the surface. ... composed of
layers of hardened lava, with individual lava flows that are up to 23
meters (75 feet) thick.
...About a dozen supervolcanoes exist on Earth; some
are on land, while others lie at the bottom of the ocean. Those found on
the seafloor are often referred to as large oceanic plateaus. Current
scientific thinking suggests that these supervolcanoes were caused by
eruptions over a period of a few million years or less--a rapid pace in
...Shatsky Rise ... is ... the only supervolcano to
have formed during a time when Earth's magnetic field reversed
frequently." This process creates "magnetic stripe" patterns in the
seafloor. "We can use these magnetic stripes to decipher the timing of
the eruption," says Sager"....
2010 March 4. NSF Release 10-037: Scientists Find Signs of "Snowball Earth" Amidst Early
Animal Evolution. Excerpt: Geologists have
found evidence that sea ice extended to the equator 716.5 million years
ago, bringing new precision to a "snowball Earth" event long suspected
to have taken place around that time.
...The new findings--based on an analysis of ancient
tropical rocks that are now found in remote northwestern Canada--bolster
the theory that our planet has, at times in the past, been ice-covered
at all latitudes.
"This is the first time that the Sturtian glaciation
has been shown to have occurred at tropical latitudes, providing direct
evidence that this particular glaciation was a 'snowball Earth' event,"
says lead author Francis Macdonald, a geologist at Harvard University.
...According to Enriqueta Barrera, program director in
NSF's Division of Earth Sciences, which supported the research, the
Sturtian glaciation, along with the Marinoan glaciation right after it,
are the greatest ice ages known to have taken place on Earth. "Ice may
have covered the entire planet then," says Barrera, "turning it into a
The survival of eukaryotes--life forms other than
microbes such as bacteria--throughout this period suggests that sunlight
and surface water remained available somewhere on Earth's surface. The
earliest animals arose at roughly the same time.
..."The fossil record suggests that all of the major
eukaryotic groups, with the possible exception of animals, existed
before the Sturtian glaciation," Macdonald says. "The questions that
arise from this are: If a snowball Earth existed, how did these
eukaryotes survive? Did the Sturtian snowball Earth stimulate evolution
and the origin of animals?"...
2009 June 21. Carbon
Dioxide Higher Today Than Last 2.1 Million
Years. ScienceDaily. Excerpt:
have reconstructed atmospheric carbon dioxide
levels over the past 2.1 million years in
the sharpest detail yet, shedding new light
on its role in the earth's cycles of cooling
The study...is the latest to rule out a drop
in CO2 as the cause for earth's ice ages growing
longer and more intense some 850,000 years
ago. But it also confirms many researchers'
suspicion that higher carbon dioxide levels
coincided with warmer intervals during the
The authors show that peak CO2 levels over
the last 2.1 million years averaged only 280
parts per million; but today, CO2 is at 385
parts per million, or 38% higher. This finding
means that researchers will need to look back
further in time for an analog to modern day
In the study, Bärbel Hönisch, a
geochemist at Lamont-Doherty Earth Observatory,
and her colleagues reconstructed CO2 levels
by analyzing the shells of single-celled plankton
buried under the Atlantic Ocean, off the coast
of Africa. By dating the shells and measuring
their ratio of boron isotopes, they were able
to estimate how much CO2 was in the air when
the plankton were alive. This method allowed
them to see further back than the precision
records preserved in cores of polar ice, which
go back only 800,000 years.
...The low carbon dioxide levels outlined
by the study through the last 2.1 million
years make modern day levels, caused by
seem even more anomalous, says Richard Alley,
a glaciologist at Pennsylvania State University,
who was not involved in the research.
"We know from looking at much older climate
records that large and rapid increase in CO2
in the past, (about 55 million years ago)
caused large extinction in bottom-dwelling
ocean creatures, and dissolved a lot of shells
as the ocean became acidic," he said. "We're
heading in that direction now."...
14 November 2006. Paleoclimatology:
Understanding the Past to Predict
the Future. By
Holli Riebeek. Scientists
use complicated climate models to predict
how Earth's climate might change in the future.
One of the best ways to test the reliability
of such models is to see how well they recreate
climates of the past.
7 November 2006 In
Ancient Fossils, Seeds of a New Debate on
Warming. By WILLIAM J. BROAD. NY Times. Excerpt:
recent years, scientists have
learned about the changing makeup of the
vanished gases by teasing subtle clues from
fossilized soils, plants and sea creatures.
They have also gained information from computer
models that predict how phenomena like eroding
rocks and erupting volcanoes have altered
the planet's evolving air. "It's getting
a lot more attention," Michael C. MacCracken,
chief scientist of the Climate Institute, a
research group in Washington, said of the growing
field. For the first time, the Intergovernmental
Panel on Climate Change, a United Nations group
that analyzes global warming, plans to include
a chapter on the reconstructions in its latest
report, due early next year.The discoveries
have stirred a little-known dispute that, if
resolved, could have major implications. One
side foresees a looming crisis of planetary
heating; the other, temperature increases that
would be more nuisance than catastrophe. Some
argue that CO2 fluctuations over the Phanerozoic
follow climate trends fairly well, supporting
a causal relationship between high gas levels
and high temperatures. Other
experts say that the fluctuations in the gas
levels often fall out of step with the planet's
hot and cold cycles, undermining the claimed
supremacy of carbon dioxide.
Highlighting the gap, the two sides clash on
how much the Earth would warm today if carbon
dioxide concentrations double from preindustrial
levels, as scientists expect. Many climatologists
see an increase of as much as 8 degrees Fahrenheit.
dioxide skeptics and others see the reconstructions
of the last 15 years as increasingly reliable,
posing fundamental questions about the claimed
powers of carbon dioxide. "Some of
the work has been quite meticulous," Thure
E. Cerling, an expert at the University of Utah
on Phanerozoic climates, said. "We are likely
to learn something."
27 December 2005. Past
Hot Times Hold Few Reasons to Relax About
New Warming. By ANDREW C. REVKIN. Excerpt:
Earth scientists with the longest frames
of reference...often seem to be the least
agitated about human-caused global warming
... these backward-looking experts have
seen it all before. ... 49 million years
ago the balmy Arctic Ocean, instead of being
covered in ice, was matted with a cousin
of the duckweed that cloaks suburban frog
ponds. The forests on the continent now
called Antarctica and on shores fringing
the Arctic were once thick and lush. And
through hundreds of millions of years, concentrations
of carbon dioxide and the other trace gases
that trap solar energy and prevent the planet
from being an ice ball have mostly been
far higher than those typical during humankind's
short existence. ... A hot, steamy earth
would be fine for most forms of life. ...Studies
of the past also show that pace matters.
The rise in temperature and greenhouse gases
during the great heat wave 55 million years
ago, while instantaneous on a geological
time scale, took thousands of years to unfold.
But the pace of the recent rise in carbon
dioxide is as much as 200 times as fast
as what has been estimated in past rapid
May 2005. Weathering
Climate Variability. ScienceMatters@Berkeley. When
it comes to weather, most of us are only
concerned with the forecast. UC Berkeley
professor Lynn Ingram is more interested
in old news. Very old. She studies how California's
climate has changed over thousands of years.
Her research could help prepare us for what
tomorrow's weather may bring.
Isotopic Temperature Record from the Vostok
TIME LINE INFORMATION TOOL. The
Climate Time Line Information Tool (CTL)
is being developed and evaluated by science
educators at the University of Colorado
and NOAA as a tool for exploring the complex
world of climate science and history.
The developers ultimately see the prototype
supporting science concepts such as systems,
cycles, energy transfer, patterns and
scale, and science as inquiry. The site's
basic design is an interactive matrix
that uses the
"powers of ten" approach to frame 1) climatic
processes and 2) specific climate events
of the past at varying time scales. Each
time scale has its own list of sources and
links to more information. The web site
is a work in progress and the developers
would like feedback from science educators
and students. Audience: college level instruction.
Archive of Past Articles for Chapter 8