2016-12-05. During last period of global warming, Antarctica warmed 2 to 3 times more than planet average.
By Robert Sanders, UC Berkeley News, Media relations.
2016-09-26. Study: Earth’s roughly warmest in about 100,000 years.
By Seth Borenstein, Associated Press.
2016-06-30. Crippled Atlantic currents triggered ice age climate change.
By Eric Hand, Science.
2016-03-02. Characterizing Interglacial Periods over the Past 800,000 Years.
By Cody Sullivan, Earth & Space Science News (EoS, AGU).
2015-12-16. Plankton Reveal New Secrets About Ancient CO2 Levels.
By Natalie Jacewicz, EoS Earth and Space Science News, AGU.
2015-07-23. Hot spells doomed the mammoths.
By Elizabeth Pennisi, Science.
2015-05-05. Ice cores show 200-year climate lag.
By Stephanie McClellan, BBC News.
2013-03-01. Study of Ice Age Bolsters Carbon and Warming Link | Justin Gillis, The New York Times. Excerpt: ...Previous research suggested that as the world began to emerge from the depths of the ice age about 20,000 years ago, warming in Antarctica preceded changes in the global carbon dioxide level by something like 800 years. That ...led some climate-change contrarians to assert that rising carbon dioxide levels were essentially irrelevant to the earth’s temperature.... ...A wave of new research in the last few years has raised the likelihood that there was actually a small gap, if any. ...Scientists have long known that ice ages are caused by variations in the earth’s orbit around the sun. When an intensification of sunlight initiates the end of an ice age, they believe, carbon dioxide is somehow flushed out of the ocean, causing a big amplification of the initial warming. Since the 1980s, scientists have been collecting a climate record by extracting long cylinders of ice from the ice sheets in Greenland and Antarctica, and from glaciers.... Air bubbles trapped in the ice give direct evidence of the past composition of the atmosphere. And subtle chemical variations in the ice itself give an indication of the local temperature at the time it was formed. The trouble is that air does not get sealed in the ice until hundreds or even thousands of years after the snow has fallen, as it slowly gets buried and compressed. ...Instead of the 800-year lag between temperature and carbon dioxide increases found in some previous research, [Dr. Parrenin’s] work suggests that the lag as the ice age started to end was less than 200 years, and possibly there was no lag at all. ...“What this does, again and more clearly than ever, is to show that the large temperature changes are tightly coupled to the large CO2 changes,” ...said Richard B. Alley, a climate scientist at Pennsylvania State University. ...The tight relationship in past climate between temperature and carbon dioxide is a major reason scientists have warned that modern society is running a big risk by burning CO2-producing fossil fuels. The level of carbon dioxide in the atmosphere has jumped 41 percent since the Industrial Revolution began in the 18th century, and scientists fear it could double or triple.... Even at the current concentration of the gas, ...increases in sea level of 25 feet or more may have already become inevitable…. Read the full article: http://www.nytimes.com/2013/03/01/science/earth/at-ice-age-end-a-smaller-gap-in-warming-and-carbon-dioxide.html
2012 Mar 5. Sharing the Blame for the Mammoth's Extinction. by Richard A. Kerr, ScienceNOW. Excerpt: The past few tens of millennia were hard times for the "megafauna" of the world. Hundreds of big-bodied species—from the mammoths of North America to the 3-meter-tall kangaroos of Australia to the 200-kilogram-plus flightless birds of New Zealand—just disappeared from the fossil record. A new, broad analysis continues the century-long debate over the loss of the big animals, coming down on the middle ground between blaming migrating humans for wiping them all out and climate change alone for doing them in. …Barnosky and environmental scientist Barry Brook of the University of Adelaide in Australia have found such a human-climate synergy operating in megafaunal extinctions when severe climate change coincided with human arrivals. A similar synergy is happening today, they say, as global warming intensifies and the human population continues to grow….
2012 February 13. A Tiny Horse That Got Even Tinier As the Planet Heated Up. By James Gorman, The NY Times. Excerpt: …Sifrhippus, the first horse... shrank from about 12 pounds average weight to about eight and a half pounds as the climate warmed over thousands of years, a team of researchers reported in the journal Science on Thursday….
…Its preserved fossils, abundant in the Bighorn Basin, provide an excellent record of its size change over a 175,000-year warm period in the Earth’s history known as the Paleocene-Eocene thermal maximum, when temperatures are estimated to have risen by 9 to 18 degrees Fahrenheit at the start, and dropped again at the end.
Scientists have known that many mammals appear to have shrunk during the warming period, and the phenomenon fits well with what is known as Bergmann’s rule, which says, roughly, that mammals of a given genus or species are smaller in hotter climates….
2009 May 7. Rise
Of Oxygen Caused Earth's Earliest
Ice Age. ScienceDaily.
Geologists may have uncovered
the answer to an age-old question
- an ice-age-old question, that is.
It appears that Earth's earliest
ice ages may have been due to the
rise of oxygen in Earth's atmosphere,
which consumed atmospheric greenhouse
gases and chilled the earth.
Alan J. Kaufman, professor of geology
at the University of Maryland, Maryland
geology colleague James Farquhar,
and a team of scientists from Germany,
South Africa, Canada, and the U.S.A.,
uncovered evidence that the oxygenation
of Earth's atmosphere - generally
known as the Great Oxygenation Event
- coincided with the first widespread
ice age on the planet.
"We can now put our hands on
the rock library that preserves evidence
of irreversible atmospheric change," said
Kaufman. "This singular event
had a profound effect on the climate,
and also on life."
Using sulfur isotopes to determine
the oxygen content of ~2.3 billion
year-old rocks in the Transvaal Supergroup
in South Africa, they found evidence
of a sudden increase in atmospheric
oxygen that broadly coincided with
physical evidence of glacial debris,
and geochemical evidence of a new
world-order for the carbon cycle.
...The result of the Great Oxidation
Event, according to Kaufman and his
colleagues, was a complete transformation
of Earth's atmosphere, of its climate,
and of the life that populated its
2007 March 23. MICROFOSSILS
UNRAVEL CLIMATE HISTORY OF TROPICAL
Earth Observatory News. Scientists
from the Royal Netherlands Institute
for Sea Research obtained for the
first time a detailed temperature
record for tropical central Africa
over the past 25,000 years. ... a
marine sediment core taken in the
outflow of the Congo River... contained
eroded land material and microfossils
from marine algae. The results show
that the land environment of tropical
Africa was cooled more than the adjacent
Atlantic Ocean during the last ice-age.
This large temperature difference
between land and ocean surface resulted
in drier conditions compared to the
current situation, which favors the
growth of a lush rainforest. These
findings provide further insight
in natural variations in climate
and the possible consequences of
a warming earth on precipitation
in central Africa. The results will
be published in this week's issue
of Science. ...ocean surface and
land temperatures behaved differently
during the past 25,000 years. During
the last ice age, temperatures over
tropical Africa were 21¡C,
or about 4¡C lower than today,
whereas the tropical Atlantic Ocean
was only about 2.5¡C colder.
By comparing this temperature difference
with existing records of continental
rainfall variability, lead author
Johan Weijers and his colleagues
concluded that the land-sea temperature
difference has by far the largest
influence on continental rainfall.
This can be explained by the strong
relationship of air pressure to temperature.
When the temperature of the sea surface
is higher than that of the continent,
stronger offshore winds reduce the
flow of moist sea air onto the African
continent. This occurred during the
last ice age and, as a consequence,
the land climate in tropical Africa
was drier than it is in today's world,
where it favours the growth of a
2006 June 8. NEW
STUDY SHOWS MUCH OF THE WORLD EMERGED
FROM LAST ICE AGE TOGETHER -
Earth Observatory. Excerpt:
The end of the recurring, 100,000-year
glacial cycles is one of the most
prominent and readily identifiable
features in records of the Earth's
recent climate history. Yet one
of the most puzzling questions
in climate science has been why
different parts of the world, most
notably Greenland, appear to have
warmed at different times and at
different rates after the end of
the last Ice Age. However, a new
study appearing in the upcoming
issue of the journal Science suggests
that, except for regions of the
North Atlantic, most of the Earth
did, in fact, begin warming at
the same time roughly 17,500 years
ago. In addition, scientists suggest
that ice core records from Greenland,
which show that average temperatures
there did not warm appreciably
until about 15,000 years ago, may
have remained in a hyper-cold state
largely as a result of events triggered
by warming elsewhere....
22 December 2005. Paleoclimatology:
Climate Close Up. While
cave rocks and ice cores provide a long-term,
annual record of past, some other climate
proxies can offer a detailed record of seasonal
temperature or rainfall changes.
22 December 2005. Paleoclimatology:
The Ice Core Record. Ice
sheets contain a record of hundreds of thousands
of years of past climate, trapped in the
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