Sentences with phrase «glacial ice core»

Atmospheric mercury deposition during the last 270 years: A glacial ice core record of natural and anthropogenic sources

And according to scientists who have 800,000 years of carbon records derived from glacial ice core samples, there is a strong link between earth temperatures and increased carbon dioxide levels in the atmosphere.

There are also many glacial ice cores as well as coral and seabed cores.

Tree rings, coral skeletons, and glacial ice cores (Figure 3) are proxies for annual temperature records, while boreholes (holes drilled deep into Earth's crust) can show temperature shifts over longer periods of time.

That includes records of bird migration patterns and the dates that cherry trees bloom, as well as analyses of air bubbles sealed inside glacial ice cores and of the shells of foraminifera, single - celled sea creatures.

Opening with a biographical sketch of Broecker — who, we learn, was born to an Evangelical suburban Chicago family, and initially drifted into his scientific vocation via a summer job in a radiocarbon dating lab — the book explains the currently - accepted Milankovitch theory of Ice Age glaciation; proceeds to an account of the Dr. David Keeling's measurements atmospheric CO2; continues with a summary of research work on glacial ice cores, sediments, and fossil pollen from around the world showing startlingly abrupt prehistoric climate changes; and moves on to the possible consequences of continued warming, closing with an account of the prospects of removing carbon dioxide from the atmosphere.

This is the period when data retrieved from glacial ice cores show the beginning of a growth in the atmospheric concentrations of several «greenhouse gases,» in particular CO2 and CH4.

Not exact matches

Climate scientists find the last glacial period interesting because ice cores in Greenland and ocean sediment cores have shown that during this period there were sharp shifts in global temperatures.

For instance, in the Tropics the temperature variations were three times as intense as today at the height of the last glacial, whereas the ice cores from Greenland indicate variations that were 70 times as intense.

In 1998, while boring near the bottom of that long core, expecting to hit bedrock, the drillers brought up ice with crystals that were startlingly different from those usually found in glacial ice.

Another thing that ice core showed, as others have before, is that the great swing in temperature between glacial and interglacial periods was invariably accompanied by great swings in the amount of greenhouse gases in the atmosphere: When the greenhouse goes up, the ice sheets go down.

The sediment cores used in this study cover a period when the planet went through many climate cycles driven by variations in Earth's orbit, from extreme glacial periods such as the Last Glacial Maximum about 20,000 years ago, when massive ice sheets covered the northern parts of Europe and North America, to relatively warm interglacial periods with climates more like tglacial periods such as the Last Glacial Maximum about 20,000 years ago, when massive ice sheets covered the northern parts of Europe and North America, to relatively warm interglacial periods with climates more like tGlacial Maximum about 20,000 years ago, when massive ice sheets covered the northern parts of Europe and North America, to relatively warm interglacial periods with climates more like today's.

Patrick Crill, an American biogeochemist at Stockholm University, says ice core data from the past 800,000 years, covering about eight glacial and interglacial cycles, show atmospheric methane concentrations between 350 and 800 parts per billion in glacial and interglacial periods, respectively.

«The first step was to reconstruct the history of global mean temperatures for the last 784,000 years, using combined data from marine sediment cores, ice cores, and computer simulations covering the last eight glacial cycles,» said Friedrich, a post-doctoral researcher at IPRC.

Ice core records are rich archives of the climate history during glacial - interglacial cycles over timescales of up to ~ 800 kyr before the current age.

Readers can look for themselves at the Greenland ice core record and decide whether there's anything of consequence going on around 41K before present that looks any different from other glacial - interglacial cycles.You can look at the GISP data yourself by downloading

Methane changes much more quickly than CO2 in the ice core records, through the Younger Dryas for example, which lasted 1000 years, methane goes back to glacial values while CO2 sort of hovers in place.

Ice core records show that atmospheric CO2 varied in the range of 180 to 300 ppm over the glacial - interglacial cycles of the last 650 kyr (Figure 6.3; Petit et al., 1999; Siegenthaler et al., 2005a).

Marine sediment cores will reveal records of past glacial - interglacial cycles while lake sediments and peat cores will reveal climate records since the last ice age.

Despite the difficulties, analyses of ice core and ocean sediment cores has shown periods of glacials and interglacials over the past few million years.

For the most recent glacial periods ice cores provide climate proxies from their ice, and atmospheric samples from included bubbles of air.

Development and comparison of layer - counted chronologies from the WAIS Divide and EDML ice cores, Antarctica, over the last glacial transition (10 - 15 ka BP).

An ultra-high resolution continuous record of methane variations during the last glacial - interglacial transition from the WAIS Divide ice core.

It covers the historical evidence, glacial retreat, ice cores...

Methane changes much more quickly than CO2 in the ice core records, through the Younger Dryas for example, which lasted 1000 years, methane goes back to glacial values while CO2 sort of hovers in place.

Samples of gas trapped in ice cores taken from the Greenland and Antarctic ice sheets have enabled scientists to determine that the level of CO2 in the atmosphere has fluctuated between approximately 180 ppm (glacial advance and colder climate in the higher latitudes) and 280 ppm (glacial retreat and warmer climate in the higher latitudes), over the past 400,000 or more years.

Oeschger and his colleagues in Bern were the first to measure the glacial - interglacial change of atmospheric CO2 in ice cores, showing that atmospheric concentrations of CO2 during the glacial period was 50 % lower than the pre-industrial concentration, a result predicted by Arrhenius nearly a century earlier.

Ice - core records of glacial - interglacial cycles provide considerable insight into the coupling of the carbon cycle and climate....

The interactions (feedbacks) between THC shifts and sea ice and glacial calving (as indicated by ice - rafted debris in deep sea core records) would tend to seriously magnify the climate changes compared to what would be expected from a similar THC shift today.

In addition to # 56, the ice core data mentioned in http://www.realclimate.org/index.php?p=13 reveal that a decrease in temperature (some 8 K) in the previous interglacial - glacial transition is followed by a CO2 decrease of ~ 50 ppmv, many thousands of years later.

But the Antarctic ice cores show nice neat glacial interglacial times.

Glacial Stratigraphy and Ice Cores

Now, Hubertus Fischer of the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, Germany, and colleagues have measured carbon isotope ratios in methane from the whole of the last glacial - interglacial transition (between 20,000 and 10,000 years before present) by analysing ice - cores.

«Late Glacial Climate History from Ice Cores.»

A study using data taken from fossils and ice cores finds that long - term temperature variability decreased four-fold from the Last Glacial Maximum (LGM) around 21,000 years ago to the start of the Holocene around 11,500 years ago.

But for me the strongest evidence that small flucuations can have tremendous impact comes from the ice core and sediment records of the glacial / interglacial cycles.

Indermühle et al. 6 found four well - defined oscillations with a peak - to - peak amplitude of about 15 p.p.m.v. during the last glacial in the Taylor Dome ice core.

Figure 2 shows our data together with earlier results from the Dome C (650 — 390 kyr bp4 and 22 — 0 kyr bp5), Vostok1, 2,3 (440 — 0 kyr bp) and Taylor Dome6 (60 — 20 kyr bp) ice cores resulting in a composite CO2 record over eight glacial cycles.

Rather, the ice core record shows clearly that changes in temperature precede changes in carbon dioxide throughout the glacial - interglacial cycle (Mudelsee, 2001), and that for the last half million years the climate system has oscillated in a self - limiting way between glacials and interglacials by about 6 deg.

The climate record obtained from two long Greenland ice cores reveals several brief climate oscillations during glacial time.

«We build on this insight to demonstrate directly from ice - core data that, over glacial — interglacial timescales, climate dynamics are largely driven by internal Earth system mechanisms, including a marked positive feedback effect from temperature variability on greenhouse - gas concentrations.»

The 800 year lag is observed in ice core records following (and prior to) Glacial Minima (Gm).

Further, there is firm evidence that migration of CO2 isn't important in the Vostok and Dome C ice cores over the past 800,000 years: each glacial / interglacial period shows the same ratio between temperature and CO2 changes: about 8 ppmv/degr.C.

The iceberg delivery of sediment containing nanoparticulate Fe during the Last Glacial Maximum (18000 — 21000 years ago) may have been sufficient to fertilize the increase in productivity required to drawdown CO2 to the levels observed in ice cores [9].

When Kaser's team looked at ice cores previously drilled at two sites high in the western Alps — the Colle Gnifetti glacier saddle 4,455 m up on Monte Rosa near the Swiss — Italian border, and the Fiescherhorn glacier at 3,900 m in the Bernese Alps — they found that in around 1860 layers of glacial ice started to contain large amounts of soot.

---- Mayewski, 2016 http://meetingorganizer.copernicus.org/EGU2016/EGU2016-2567.pdf «The demonstration using Greenland ice cores that abrupt shifts in climate, Dansgaard - Oeschger (D - O) events, existed during the last glacial period has had a transformational impact on our understanding of climate change in the naturally forced world.

It is the first study to directly link past glacial events with annual data from ice cores — cylindrical samples drilled from the glacier — extracted from the same ice mass.

The researchers did not notice an obvious relationship between the accumulation of ice recorded in the ice core and glacial fluctuation.

The peak of the last glacial — Wisconsin in NA and Wurm in Europe — was probably about 8 degrees C colder than the present based on the Vostok ice core.

230 P. E. Biscaye, F. E. Grousset, M. Revel, S. VanderGaast, G. A. Zielinski, A. Vaars, and G. Kukla, «Asian provenance of glacial dust (stage2) in the Greenland Ice Sheet Project 2 Ice Core, Summit, Greenland,» Journal of Geophysical Research 102:765 - 781 (1997).