Sentences with phrase «ice concentration during»

While sea ice concentrations were slightly lower in June during the early LIG (130 ka) and the middle LIG (125 ka) compared to PI concentrations, the largest difference can be observed in September when sea ice concentrations during the early and middle LIG were distinctly lower then those modeled for the PI.

Not exact matches

Data from the new ice core array illustrates that Antarctic lead concentrations reached a peak in 1900 and remained high until the late 1920s, with brief declines during the Great Depression and the end of World War II.

Year - round ice - free conditions across the surface of the Arctic Ocean could explain why Earth was substantially warmer during the Pliocene Epoch than it is today, despite similar concentrations of carbon dioxide in the atmosphere.

Year - round ice - free conditions across the surface of the Arctic Ocean could explain why Earth was substantially warmer during the Pliocene Epoch than it is today, despite similar concentrations of carbon dioxide in the atmosphere, according to new research carried out at the University of Colorado Boulder.

«Detailed chemical measurements in Antarctic ice cores show that massive, halogen - rich eruptions from the West Antarctic Mt. Takahe volcano coincided exactly with the onset of the most rapid, widespread climate change in the Southern Hemisphere during the end of the last ice age and the start of increasing global greenhouse gas concentrations,» according to McConnell, who leads DRI's ultra-trace chemical ice core analytical laboratory.

How sea ice concentrations around Antarctica differed from average during November 2016.

Historically, methane concentrations in the world's atmosphere have ranged between 300 and 400 nmol / mol during glacial periods commonly known as ice ages, and between 600 to 700 nmol / mol during the warm interglacial periods.

Acidity decline in Antarctic ice cores during the Little Ice Age linked to changes in atmospheric nitrate and sea salt concentratioice cores during the Little Ice Age linked to changes in atmospheric nitrate and sea salt concentratioIce Age linked to changes in atmospheric nitrate and sea salt concentrations.

It has long been suspected that the low solar activity during the Maunder Minimum was one of the causes of the Little Ice Age, although other factors like a small drop in greenhouse gas concentrations around 1600 and strong volcanic eruptions during that time likely played a role as well.

We know from data that we have caused the CO2 concentration in the atmosphere to rise sharply during the past century: it is now much higher than any time during the past 650,000 years (which is as far back as reliable ice core data exist).

On a related note: Does anyone here know where the best source would be for getting a detailed chart of Be-10 concentrations from ice cores plotted against global temps during the past 10,000 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.

Dr. Archer has worked on the ongoing mystery of the low atmospheric CO2 concentration during glacial time 20,000 years ago, and on the fate of fossil fuel CO2 on geologic time scales in the future, and its impact on future ice age cycles, ocean methane hydrate decomposition, and coral reefs.

Fig. 2 The CO2 concentration of the atmosphere during the Holocene, measured in the ice cores from Antarctica until 1958, afterwards Mauna Loa.

Howell points out that concentration of MYI in the region is well below the historical average and that it is likely the seasonal first - year ice will clear during the melt season.

Infact during the Ordovician period the CO2 concentrations were 4000 ppm, and yet earth had an Ice Age, explain that, I bet you can't.

During our 200,000 - or - so years on this planet, CO2 concentrations have largely stayed below 300 ppm, as ice cores prove.

As the BRT stated, «Research suggests that, during the time of whelping and nursing, bearded seals prefer areas where the percent concentration of sea ice is > 25 %.

Thus, during the optimal season for whelping, 99 % of their foraging habitat is covered by ice concentrations greater than 15 % and as high as 100 %.

«It is very likely that the rate of global mean sea level rise during the 21st century will exceed the rate observed during 1971 — 2010 for all Representative Concentration Pathway (RCP) scenarios due to increases in ocean warming and loss of mass from glaciers and ice sheets.

As researchers documented in this graph, the region had experienced increasing precipitation during the Little Ice Age, followed by a sharp drying trend that began in the late 1700s, which triggered Kilimanjaro's retreat long before CO2 ever reached significant concentrations.

Lower ice concentrations in 2011 relative to 2007 in late May indicate increased sensitivity of the arctic ice cover to atmospheric dynamical forcing, with implications for ice transport during summer.

Morison and Untersteiner (University of Washington); 5.6 Million Square Kilometers; Heuristic Estimate is based on recent observations, including the previous winter Arctic Oscillation (AO), ice concentrations observed during North Pole Environmental Observatory (NPEO) hydro surveys, atmospheric and ice surface conditions observed with NPEO buoys and Web Cams, and recent ice trajectories.

(a, b) Annual - mean sea ice concentration in the CTL and SW experiments, and (c) SST anomalies during the last 50 years of the latter simulation.

During the late LIG (120 ka), on the other hand, September sea ice concentrations seems to have been quite similar to the PI (Fig. 4).

Based on a proxy reconstruction, ice - free summers also occurred during a late Miocene warm climate with simulated atmospheric CO2 concentrations of 450 ppm8, a value we also might reach in the near future.

During the MIS 5 interstadials, a seasonal sea ice cover and ice - edge conditions seem to have been most prominent, with minimum sea ice concentrations towards almost ice - free summers during MIS 5e (Eemian)(FigDuring the MIS 5 interstadials, a seasonal sea ice cover and ice - edge conditions seem to have been most prominent, with minimum sea ice concentrations towards almost ice - free summers during MIS 5e (Eemian)(Figduring MIS 5e (Eemian)(Fig. 3b).

Core PS2757 - 8 is located on the southern Lomonosov Ridge close to the Laptev Sea continental margin, an area that is predominantly covered by sea ice (Fig. 1; 7/10 summer sea ice concentration) but may occasionally be even ice - free during summer.

Nørgaard - Pedersen, N., Mikkelsen, N., Lassen, S. J., Kristoffersen, Y. & Sheldon, E. Reduced sea ice concentrations in the Arctic Ocean during the last interglacial period revealed by sediment cores off northern Greenland.

The most likely explanation for the linear trend [in sea ice decline] during the satellite era from 1979 onwards is the almost linear increase in CO2 concentration during that period.

Wenk Physics Institute, University of Bern, CH — 3012 Bern, Sidlerstrasse 5, Switzerland Studies on air trapped in old polar ice1, 2 have shown that during the last ice age, the atmospheric carbon dioxide concentration was probably significantly lower than during the Holocene — about 200 p.p.m. rather than 270 p.p.m.. Also, Stauffer et al. 3 recently showed by detailed analyses of Greenland ice cores, that during the ice age, between about 30,000 and 40,000 yr BP, the atmospheric CO2 level probably varied between 200 and 260 p.p.m..

Taken together, the average of the warmest times during the middle Pliocene presents a view of the equilibrium state of a globally warmer world, in which atmospheric CO2 concentrations (estimated to be between 360 to 400 ppm) were likely higher than pre-industrial values (Raymo and Rau, 1992; Raymo et al., 1996), and in which geologic evidence and isotopes agree that sea level was at least 15 to 25 m above modern levels (Dowsett and Cronin, 1990; Shackleton et al., 1995), with correspondingly reduced ice sheets and lower continental aridity (Guo et al., 2004).

The great thing is that, since we can make good estimates of the changes in solar radiation, changes in the Earth's albedo due to melting ice, and changes in atmospheric CO2 concentration during the ice ages, scientists can directly calculate the sensitivity of the climate to changes in the atmospheric CO2 concentration.

In his testimony, he said that he arrived at that figure because that was how far CO2 concentration had fallen during the Cenozoic before polar ice sheets appeared.

The fact that the earth appears to have gone through huge changes in atmospheric CO2 concentration over geologic eras, while the estimated temps went from 12degC to 22 deg C regardless of «Snowball Earth» or «Cretaceous Hot House» with both hot and cold periods occurring during both high and low CO2 regimes and both with and without ice caps argues very strongly that we do not understand the climate mechanism at all.

The models heavily relied upon by the Intergovernmental Panel on Climate Change (IPCC) had not projected this multidecadal stasis in «global warming»; nor (until trained ex post facto) the fall in TS from 1940 - 1975; nor 50 years» cooling in Antarctica (Doran et al., 2002) and the Arctic (Soon, 2005); nor the absence of ocean warming since 2003 (Lyman et al., 2006; Gouretski & Koltermann, 2007); nor the onset, duration, or intensity of the Madden - Julian intraseasonal oscillation, the Quasi-Biennial Oscillation in the tropical stratosphere, El Nino / La Nina oscillations, the Atlantic Multidecadal Oscillation, or the Pacific Decadal Oscillation that has recently transited from its warming to its cooling phase (oceanic oscillations which, on their own, may account for all of the observed warmings and coolings over the past half - century: Tsoniset al., 2007); nor the magnitude nor duration of multi-century events such as the Mediaeval Warm Period or the Little Ice Age; nor the cessation since 2000 of the previously - observed growth in atmospheric methane concentration (IPCC, 2007); nor the active 2004 hurricane season; nor the inactive subsequent seasons; nor the UK flooding of 2007 (the Met Office had forecast a summer of prolonged droughts only six weeks previously); nor the solar Grand Maximum of the past 70 years, during which the Sun was more active, for longer, than at almost any similar period in the past 11,400 years (Hathaway, 2004; Solankiet al., 2005); nor the consequent surface «global warming» on Mars, Jupiter, Neptune's largest moon, and even distant Pluto; nor the eerily - continuing 2006 solar minimum; nor the consequent, precipitate decline of ~ 0.8 °C in TS from January 2007 to May 2008 that has canceled out almost all of the observed warming of the 20th century.

Table 1 summarizes mean variation rates of temperature, sea level and GHG concentrations during (A) the last termination (19 — 10 kyr), (B) the Holocene (10 kyr to mid-19th century), (C) mid-19th century to mid-1970s, and (D) mid-1970s to 2005, based on ice core studies [2], IPCC - 2001 and IPCC - 2007 [3], NASA - GISS [4], CSIRO Marine and Atmospheric Research [5], UK Meteorological Office [6] datasets and science journals.

More than 20 years ago, analyses of greenhouse gas concentrations in ice cores showed that downward trends in CO2 and CH4 that had begun near 10,000 years ago subsequently reversed direction and rose steadily during the last several thousand years.

The discovery in ice core records that atmospheric concentrations of two potent greenhouse gases, carbon dioxide and methane, have decreased during past glacial periods and peaked during interglacials indicates important feedback processes in the Earth system.

Morison and Untersteiner (University of Washington); 5.6 Million Square Kilometers; Heuristic Estimate is unchanged from last month and is based on the previous winter Arctic Oscillation (AO), ice concentrations observed during North Pole Environmental Observatory (NPEO) hydro surveys, atmospheric and ice surface conditions observed with NPEO buoys and Web Cams, and recent ice trajectories.

Ice concentrations have declined significantly along the northern Northwest Passage route during July and early August and clearing along the western end of the route is trending a week earlier than in 2007.