Sentences with phrase «snowball earth glaciations»

«Studying Snowball Earth glaciations can tell us just how bad it can get, in which case life as we know it would probably not survive,» says geologist Linda Sohl of Columbia University's Center for Climate Systems Research and NASA's Goddard Institute for Space Studies.

Not exact matches

«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.

The first Ediacaran to begin crawling around would have discovered a world devoid of predatory animals, with a seafloor covered either in thick bacterial mats or toxic sediment and, possibly, a climate thawing from a worldwide glaciation event known as «Snowball Earth.»

Including sponge - like animals (850 to 635 million years ago, which pre-date the end of the hypothesized Snowball - Earth - type Marinoan glaciation — 2010 discussion at: Maloof et al, 2010; NSF press release; Hillary Parker, News at Princeton, 2010; and James O'Donoghue, New Scientist, August 17, 2010), worms, molluscs, and arthropods (joint - footed animals), invertebrates are among the most successful animals today.

One of the extreme events, which has mystified scientists for long, took place 717 million years ago and is called «snowball Earth» — the largest glaciation event in history during which the planet was covered almost entirely in ice.

[10] Earlier still, a 200 - million year period of intermittent, widespread glaciation extending close to the equator (Snowball Earth) appears to have been ended suddenly, about 550 million years ago, by a colossal volcanic outgassing which raised the CO2 concentration of the atmosphere abruptly to 12 percent, about 350 times modern levels, causing extreme greenhouse conditions and carbonate deposition as limestone at the rate of about 1 mm per day.

This chemical weathering process is too slow to damp out shorter - term fluctuations, and there are some complexities — glaciation can enhance the mechanical erosion that provides surface area for chemical weathering (some of which may be realized after a time delay — ie when the subsequent warming occurs — dramatically snow in a Snowball Earth scenario, where the frigid conditions essentially shut down all chemical weathering, allowing CO2 to build up to the point where it thaws the equatorial region, at which point runaway albedo feedback drives the Earth into a carbonic acid sauna, which ends via rapid carbonate rock formation), while lower sea level may increase the oxidation of organic C in sediments but also provide more land surface for erosion... etc..

With respect to the dismissal of the model, we point out that we have separately applied the model to the great Permo - Carboniferous glaciation on Pangaea and to the Snowball Earth problem (although some people do not like one of the solutions it produces).

The concept of «snowball earth» is based on interpretation of some geological formations as evidence of glaciation — an interpretation that is not shared by a number of Canadian geologists specializing in glaciation (an important phenomenon in Canadian geology).

Today Earth is a pretty temperate place, but about 700 million years ago ice covered the planet from pole to pole, in an extreme glaciation period often called «Snowball Earth.»

Given that a CO2 doubling or halving is equivalent to a 2 % change in solar irradiance [66] and the estimate that solar irradiance was approximately 6 % lower 600 Ma at the most recent snowball Earth occurrence [113], figure 7 implies that about 300 ppm CO2 or less was sufficiently small to initiate glaciation at that time.

«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.»

The last of these so - called «Snowball Earth» glaciations ended around 635 million years ago when complex life was just starting to develop.

[65] Earlier still, a 200 - million year period of intermittent, widespread glaciation extending close to the equator (Snowball Earth) appears to have been ended suddenly, about 550 Ma, by a colossal volcanic outgassing that raised the CO2 concentration of the atmosphere abruptly to 12 %, about 350 times modern levels, causing extreme greenhouse conditions and carbonate deposition as limestone at the rate of about 1 mm per day.

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.