Sentences with phrase «global glaciations»

A similar low and high arsenic content accompanied the coming and going of global glaciations at around 0.7 billion years ago, which is when Earth first saw the appearance of complex life.

«In addition, this early phase of evolutionary divergence appears to have preceded the extreme climate changes that led to Snowball Earth, a period marked by severe long - term global glaciation that lasted from about 720 to 635 million years ago,» Dohrmann says.

This is also a period when Earth experienced its first known global glaciation.

Pierrehumbert RT 2004: High levels of atmospheric carbon dioxide necessary for the termination of global glaciation Nature 429, 646 - 649.

«In particular, this mechanism may have contributed to Earth's entry into a long period of global glaciation around 700 million years ago, a theory known as the Snowball Earth hypothesis.»

Three areas of particular interest and debate are the «faint young Sun paradox,» the role of organisms in shaping Earth's atmosphere, and the possibility that Earth went through one or more «snowball» phases of global glaciation.

Not exact matches

So the fact that we have this very strong drying in the tropics during glaciation would argue for a strong feedback of water vapor concentration to the global climate during glacial - interglacial cycles.»

The late Proterozoic — the time period beginning less than a billion years ago following this remarkable chapter of sustained low levels of oxygen — was strikingly different, marked by extreme climatic events manifest in global - scale glaciation, indications of at least intervals of modern - like oxygen abundances, and the emergence and diversification of the earliest animals.

Michael Mann, a meteorology professor at Penn State who was not involved with the study, said it's «speculative» but «plausible» that global climate models have been underestimating climate sensitivity by assuming too much cloud glaciation.

The current global cycle of glaciation dates to this period and might have been triggered by a transformation of the world's ocean currents, which a slender rib of land separating Atlantic and Pacific would naturally explain.

During the preceding glaciation (the LGM, or «Last Glacial Maximum»), global mean temperature was approximately 6 Celsius degrees cooler, sea levels were at least 120 meters lower than at present.

During glaciation, water was taken from the oceans to form the ice at high latitudes, thus global sea level drops by about 120 meters, exposing the continental shelves and forming land - bridges between land - masses for animals to migrate.

The new production circumstances of Code Unknown gave him the space and budget to retry and perfect some of the thematic strategies risked in the glaciation trilogy, but it is the combination of the fates of semi-established African residents in Paris with those of Romanians in the country illegally and begging in the streets that makes the film feel more global in scope than his earlier work.

I'm a fish geneticist so I won't bother commenting on «paleo - ocean current - ology», but it seems to me that glaciation would result in a reduction of fresh water inputs to the North Atlantic (during the ice age) and would therefore be quite different from the mechanism in question (which is related to early phases of global warming).

As astronomical cycles they are predictable into the future and will cause another ice age probably in around 50,000 years (that depends on where the threshold for glaciation is, and what future CO2 levels will be at that time), but there is no way the Milankovich cycles could explain the current global warming.

Without knowing the bigger picture (i.e having right global model of glaciations - deglaciations), the «local» responses may be misleading, especially for practical purposes.

During the preceding glaciation (the LGM, or «Last Glacial Maximum»), global mean temperature was approximately 6 Celsius degrees cooler, sea levels were at least 120 meters lower than at present.

The earth has had significant Global Warming for some 20,000 years now... The only real argument is to the degree that mans activity has augmented that... We just came out of one - point - five - million years of continuous glaciation with sheets of two mile thick ice down past the 44th parallel... I will cheerfully deal with warming issues over that, any day...

Clearly Antarctic glaciation was not part of a global event, but a regional one.

So what are you willing to do to prevent rapid cooling into the next glaciation — rather than the lemming mantra of global warming?

C: Datasets suggesting a drying environment at 2.5 Ma, shown by λ 18O from benthic foraminifera, a proxy for global temperature, smoothed with a Gaussian window of 200 ky; eustatic sea level; and magnetic susceptibility, a proxy for ice rafted debris and Northern Hemisphere glaciation.

However, we know that severe and abrupt climate shifts of global extent have occurred (infrequently) during glaciations, and almost never during warmer interglacial periods such as the current Holocene.

The few degrees of global temperature rise since the depths of the Pleistocene glaciation (say 18,000 ybp) can be seen as a short - term reversal of a long - term cooling trend.

In 1974 when the Club of Rome formulated it, the consensus was that global cooling (due to dust and pollution from natural volcanic eruptions and from industry) was screening out sunlight, and we were in for runaway glaciation and a new ice age.

Clarke et al.'s work is published in Nature Geoscience and uses a regional glaciation model driven by global climate model output to examine possible future changes to glaciers in western Canada.

Such glaciation, snow and cold would cause catastrophic harm to agriculture with consequent global famines.

Cenozoic evolution of Antarctic glaciation, the circum - Antarctic Ocean, and their impact on global paleoceanography

In a paper «Global warming preceded by increasing carbon dioxide concentrations during the last deglaciation», Shakun et al. (Nature 2012) contend that rising temperature at the end of the last Pleistocene glaciation were preceded by increasing atmospheric CO2.

As far as CO2 «signatures» go, it is hard to verify that CO2 is having any warming, as in Global Warming» impact and the black carbon associated with «the Social Cost of Carbon» has a more easily verified impact which is to reduce snow fields which are the lead in to glaciation.

My PhD research focussed on the Neoproterozoic, a period in Earth history when some researchers believe glaciation was global, covering continents and oceans.

In my search to be informed about all this global warming and co2 concern I found the Orbital Variations in connection with the Stages of Glaciation very interesting.

* * The evidence shows global warming AND glaciations near the P - Tr.

As the ice sheets waxed and waned, global climate drifted steadily toward cooler conditions characterized by increasingly severe glaciations and increasingly cool interglacial phases.