Sentences with phrase «of glacial conditions»

After the initial development of glacial conditions, the Earth system alternated between two modes, one of cold temperatures and growing glaciers and the other of relatively warm temperatures (although much cooler than today) and retreating glaciers.

A map of sea ice extent at the climax of the Last Glacial Maximum (both perennial and seasonal ice), prepared with the help of a colleague, makes it possible to discuss what genetic and fossil evidence can tell us about the probable effects of glacial conditions on polar bears and ringed seals.

Not exact matches

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Instead, the fossil record indicates they vanished during the Earth's glacial - interglacial transition, which occurred about 12,000 years ago and led to much warmer conditions and the start of the current Holocene period.

But the topography is just one part of the story — coupling that with vastly improved satellite data as well as a better understanding of glacial processes and oceanographic and climate conditions is «probably what we need to do in all of these places,» Siegert says.

«Humans in this region thrived through the Toba event and the ensuing full glacial conditions, perhaps as a combined result of the uniquely rich resource base of the region and fully evolved modern human adaptation,» study authors noted.

For example, Jessica tell Mike how she and her colleagues pulled together a sweeping collection of paleoclimate evidence to reveal how the jet stream contracted and twisted in glacial boundary conditions, rather than moving monolithically south.

Bartek, L.R., and Anderson, J.B., 1991, Facies distribution resulting from sedimentation under polar interglacial climatic conditions within a high - latitude marginal basin, McMurdo Sound, Antarctica: in J.B. Anderson and G.M. Ashley, eds., Paleoclimatic Interpretation of Glacial Marine Deposits, Special Publication 261, Geological Society of America, Boulder, p. 27 - 49.

The sequence of climatic forcings and responses during deglaciations (transitions from full glacial conditions to warm interglacials) are well documented.

The current secondary contact is thought to result from a range expansion associated with the amelioration of climatic conditions after the last glacial maximum (∼ 18000 ya)[20], although previous glacial / interglacial cycles during the Pleistocene may have provided multiple opportunities for vicariant and past hybridization events.

Rather than waiting for the glacial progress of modern biomedical research, which needs decades to assemble sufficient evidence to get an application for funding for a clinical trial past skeptical reviewers, anyone with a brain or neurological condition should simply experiment with a ketogenic diet themselves to see if it helps.

Over that time, we were faced with an incredible diversity of conditions: from glacial river crossings to decommissioned forest service roads, endless sand dunes and treacherous alpine crossings.

During the last part of the Pleistocene there were actually five major periods of glaciation with four periods of warmer non glacial conditions between them.

Equilibrium sensitivity, including slower surface albedo feedbacks, is 6 °C for doubled CO2 for the range of climate states between glacial conditions and ice - free Antarctica.»

I think these are simply features of global climate that are embedded and as predictable as other large features like hurricane patterns, the gulf stream, the jet stream, sea ice extent and mass, global glacial conditions, sea level etc..

The results of these simulations show that dust − climate feedbacks, perhaps set off by orbital forcing, push the system in and out of extreme cold conditions such as glacial maxima.

The conclusion that they survived over at least two glacial cycles, where the amplitude of environmental change in the Arctic is quite large, suggests they have under natural conditions the ability to adapt / survive such changes.

[Response: All forcings are calculated by changing the boundary conditions (in this case the distribution of glacial ice, and looking to see what the change in net radiation is while keeping everything else constant.

Aren't the neo-glacial readvances and other signs of a cooling climate during the past 3,000 years evidence of a gradual return to glacial conditions (prior to the anthropogenic influence brought on by the industrial revolution)?

It is also possible for cold climates to increase chemical weathering in some ways, by lowering sea level to expose more land to erosion (though I'd guess this can also increase oxydation of C in sediments) and by supplying more sediments via glacial erosion for chemical weathering (of course, those sediments must make it to warmer conditions to make the process effective — downhill and downstream, or perhaps via pulsed ice ages -LRB-?)-RRB-.

If C02 is the largest single contributing factor to the Greenhouse Effect (because supposedly water vapor is only involved as a feedback to primary chemistry involving C02 itself), and C02 lags temperature increases (as has been stated on this very blog), how has the Earth ever returned to colder glacial conditions following periods of warming?

Although the sensitivity of climate does change itself as the boundary conditions change, the past (PETM, glacial - interglacial cycles, etc) does not support sensitivities as low as 1 degree per doubling of CO2, and it doesn't support very high ones (like 10 degrees per doubling) either.

What I'm wondering is if our activities could actually be putting an end to the past few million years of the interglacial - glacial cycle and return to the conditions that existed around 4 million years ago?

I can't imagine humans wanting to enter conditions of the glacial period - unless skiing becomes very popular.

«In spite of calls for urgent reform and broad recognition that the current rules penalised solar power and rewarded network gold - plating, governments have not even made glacial progress in the past five years, with the unpopular result of high electricity prices driven by the cost of network infrastructure to service people's desire for air conditioning.

Carbon starvation, which apparently sometimes occurs during glacial periods due to the low levels of CO2 that are reached, has the same effect on C3 plants * trees, shrubs, and such) as do warm, dry conditions when the warm is excesaive.

Dr. Soon: Earth's climate system dynamically oscillates between icehouse and hothouse conditions in geological time or, to a lesser degree, between the glacial and interglacial climates of the last 1 — 2 million years.

Müller, C. Reconstruction of the paleontological conditions at the Laptev Sea continental margin during the last two glacial / interglacial cycles based on sedimentological and mineralogical investigations.

This type of behavior is especially evident during transitions from glacial to interglacial conditions, when climate is affected by a wide variety of time - varying influences and is relatively unstable.

With current greenhouse gas levels now in the range of 400 - 405 parts per million coinciding with substantial jumps in glacial melt and sea level rise, it may be worth taking a look back at times in the geological past when atmospheric heating conditions were similar to those seen today.

Conditions have been so warm and dry that at least one glacial outburst flood has occurred on the slopes of Mt. Shasta as winter ice accumulation decreases and summer melt accelerates.

(2) The glacial epoch itself seemed to have been a relatively stable condition that lasted millions of years.

(29) Another respected climatologist explained that the old view of «a grand, rhythmic cycle» must be replaced by a «much more rapid and irregular succession,» in which the Earth «can swing between glacial and interglacial conditions in a surprisingly short span of millennia (some would say centuries).»

The most likely candidate for that climatic variable force that comes to mind is solar variability (because I can think of no other force that can change or reverse in a different trend often enough, and quick enough to account for the historical climatic record) and the primary and secondary effects associated with this solar variability which I feel are a significant player in glacial / inter-glacial cycles, counter climatic trends when taken into consideration with these factors which are, land / ocean arrangements, mean land elevation, mean magnetic field strength of the earth (magnetic excursions), the mean state of the climate (average global temperature), the initial state of the earth's climate (how close to interglacial - glacial threshold condition it is) the state of random terrestrial (violent volcanic eruption, or a random atmospheric circulation / oceanic pattern that feeds upon itself possibly) / extra terrestrial events (super-nova in vicinity of earth or a random impact) along with Milankovitch Cycles.

each period of warming during the descent to the next glacial stage should be more intense than the previous ones, as climatic variability increases outside the warm conditions of an interglacial climatic optimum.

Other processes must be responsible for the 40 - to 50 - ppm pCO2 drawdown during the initial transition from interglacial to glacial conditions as well as for a comparable pCO2 increase during the latter part of glacial terminatins.

J, You said: «The model being debated here would imply truly massive swings in CO2 between glacial and interglacial conditions (on the order of 1000 ppmv fluctuations).

Our results show that dust − climate feedbacks can explain the final push into extreme glacial conditions for both GMT and pCO2, thereby explaining about one - fourth of the total interglacial − glacial change for both properties.

«The time span of the last 130,000 years has seen the global climate system switch from warm interglacial to cold glacial conditions, and back again.

Sometime in the long slow drift of continents following the breakup of Gondwanaland — conditions became ripe for the repeated glacials and interglacials that we have seen for the past few million years.

Together these two feedbacks fully account for the global temperature swings from glacial to interglacial conditions (Fig. 2C), with a climate sensitivity of 3/4 °C per W / m2 of forcing, or 3 °C for doubled CO2 forcing.

This overshoot is caused predominantly by the reduction of the meltwater in the northern North Atlantic associated with the retreat of the large amount of sea ice, an effect that becomes dominant when the subpolar North Atlantic is covered by sea ice as in the glacial condition.

These «hothouse Earths» supported life, but would be inhospitable to today's life - forms, adapted as they are to the conditions of a CO2 - poor glacial world.

At a tipping point the accumulation of snow is rapid causing a chaotic shift to glacial conditions.

In 2002, the Larsen B ice shelf collapsed; in 2003, the World Glacial Monitoring Service reported that «The recent increase in the rates of ice loss over reduced glacier surface areas as compared with earlier losses related to larger surface areas (cf. the thorough revision of available data by Dyurgerov, 2002) becomes even more pronounced and leaves no doubt about the accelerating change in climatic conditions.»

above: the calling - card of an ancient ice - age - an outcrop in Namibia of an ancient (Proterozoic) tillite of glacial origin, overlain by a dolomitic «cap - carbonate» sequence of marine origin, deposited in warmer post-glacial conditions.

Climate model simulations of the Last Glacial Maximum show an even stronger Bodélé LLJ compared with that of the present, and dated evidence points to the conditions under which deflation would have been capable of excavating the depression which was later partly filled by paleolake Megachad (31).