Sentences with phrase «by ice core data»

Harder, S.L., D.T. Shindell, G.A. Schmidt, and E.J. Brook, 2007: A GCM study of CH4 emissions during the Holocene and glacial - interglacial transitions constrained by ice core data.

It is my contention that the quiescence of CO2 levels, as indicated by the ice core data, indicates that the CO2 regulatory system is a fast one.

Even the highest parts of the island, two miles above sea level at the Summit Station, underwent melting, an occurrence shown to happen every 150 years by ice core data.

This is the common sceptic claim that «the prediction is that CO2 is a major driver is refuted by the ice core data which shows it isn't, therefore, CO2 is not a major driver of climate change»

This is fully supported by the ice core data.

However, the geographic variability of these periodicities indicated by ice core data is not captured in model simulations.»

The AMO during the Little Ice Age was characterized by a quasi-periodicity of about 20 years, while the during the Medieval Warm Period the AMO oscillated with a period of about 45 to 65 years... The observed intermittency of these modes over the last 4000 years supports the view that these are internal ocean - atmosphere modes, with little or no external forcing... However, the geographic variability of these periodicities indicated by ice core data is not captured in model simulations.»

This follows a pattern that, supported by ice core data, C02 levels follow temperature changes.

However, if you are unconvinced by the ice core data, it is supported by physical evidence.

Not exact matches

Using data from 16 ice cores collected from widely spaced locations around the Antarctic continent, including the South Pole, a group led by Joe McConnell of the Desert Research Institute (DRI) in Reno, Nevada, created the most accurate and precise reconstruction to date of lead pollution over Earth's southernmost continent.

The team, led by Dr Kira Rehfeld and Dr Thomas Laepple, compared the Greenland data with that from sediments collected in several ocean regions around the globe, as well as from ice - core samples gathered in the Antarctic.

By comparing the EPICA air bubbles data to that from other ice cores and marine sediments, researchers can create a reliable picture of the climate over time.

The study, by an international team of scientists led by the University of Cambridge, examined how changes in ocean currents in the Atlantic Ocean were related to climate conditions in the northern hemisphere during the last ice age, by examining data from ice cores and fossilised plankton shells.

From at least Lorius et al (1991)-- when we first had reasonable estimates of the greenhouse gases from the ice cores, to an upcoming paper by Schneider von Deimling et al, where they test a multi-model ensemble (1000 members) against LGM data to conclude that models with sensitivities greater than about 4.3 ºC can't match the data.

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

I have recently attended a lecture by Dr. David Dallmeyer of the U.of Ga. concerning data availble from ice cores concerning the natural patterns of heating and cooling.

The authors compared recently constructed temperature data sets from Antarctica, based on data from ice cores and ground weather stations, to 20th century simulations from computer models used by scientists to simulate global climate.

The work by Vinther and colleagues in Southern Greenland is therefore key to helping calibrate the Greenland ice core records, and impressively, the correlations to the older data are as good as to the recent record, allowing us to have a little more confidence in the even longer term proxy data for this region.

This data clearly indicates that the planet is getting warmer, and this correlates with increased greenhouse gases, both now and in the distant past (as verified by ice core samples).

BPL: The warming trend is not twenty years old, but 165 years old by direct measurements and perhaps 250 years old if you include ice - core data.

I would also add that the «prediction» made by # 11 about what a D - O event would look like is based on the Greenland ice core records, and the picture of «abrupt warming / slow cooling» picture comes from the data on millennial timescales.

The highly accurate ice core data sets rathr precise dates for three major (and tropical) eruptions for which previous studies by traditional methods of paleogeology gave only poorer approximations.

In our current paper, we reinforce this proposed re-dating by looking at ice core data published since 2010, from both Greenland (NEEM S1 (Sigl et al., 2013)-RRB- and Antarctica (WDC06A (Sigl et al., 2013), Law Dome (Plummer et al., 2012)-RRB- as well as the Antarctic DML core (Traufetter et al., 2004).

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.

Stomata data show a much larger variation of CO2 in the last millenium (besides higher values in general), in part caused by the smoothing effect of relative slow closing air bubbles in ice cores...

I just tested this by trying to recall some details about recent improvements in understanding the data from the ice cores.

Atmospheric CO2 is estimated by IPCC to have been around 290 ppmv in 1901 (based on ice core data) and was measured at 369 ppmv in 2000 (at Mauna Loa), for a 27 % increase.

Since 1880 to about 1925 more than 80 data series seleced by me to represent typical yearly averagees (when possible) we have nearly identical CO2 values than the ice cores shows!!!

Vostok Data The Vostok ice core sample was obtained by drilling down into the ice above Lake Vostok to a depth of 3623m.

For a complete technical description of other CO2 data problems (including ice core data), see my reference source — an article by a geochemist and geophysicist (Tom V. Segalstad, Carbon Cycle Modeling..., http://www.co2web.info/ESEF3VO2.pdf).

Mann's graphic represented a reconstruction of past temperatures, not from thermometers or satellites, but by analysing data from proxies, such as tree - ring width, corals, and ice cores.

Also, the Greenland ice core data do agree pretty good with sulfate emissions estimates, but Greenland is located downwind of the US and Canada and does not represent global trends impacted by developing countries.

I also explained I don't have any real beefs with ice core data but if you want to state something specific I'm sure I can find something to cast doubt upon it as very little in this debate is writ in granite, confirmation bias is rampant, overconfidence abounds, the race to publish by inexperienced youngsters on the tenure track is heated, and pal review let's just about anything that supports the consensus view get published while simultaneously quashing anything contrary.

The best candidates there would seem to be CET (Central England Temperature) for 1660 - 1900, the various ice core samples, and the International Tree Ring Data Bank maintained by NOAA.

«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.»

This work is the first to consistently recreate the event by computer modeling, and the first time that the model results have been confirmed by comparison to the climate record, which includes such things as ice core and tree ring data.

Granted the back - ground level is similar to that at Mauna Loa, but the point is, the ice - core data appears to suffer from the same problem as Stomata and is affected by local circumstances considerably too.

This is only suggested by ice - core paleoclimate data which is ultimately uncheckable by direct empirical observation.

I agree with you in one respect: to sort out all the nonsense about climate, one can go a long way just by meditating on ice core data.

Third, the ice core data how conclusively that, during natural climate cycling, changes in temperature precede changes in carbon dioxide by an average 800 years or so (Fischer et al, 1999; Indermuhle et al, 2000; Mudelsee, 2001; Caillon et al, 2003); similarly, temperature change precedes carbon dioxide change, in this case by five months, during annual seasonal cycling (Kuo, Lindberg and Thomson, 1990).

Obviously, the study is hampered by the limitation of the climate reconstruction (as well as by the few C13 ice core data).

Very few (1 - 2 points) of ice core C13 data (Francey tellus, 99) suggest that this drawdown was caused by additional terrestrial carbon storage (Joos et al, GRL, 99; Trudinger, Tellus, 99).

The Etheridge ice core data of CO2 indicate that CO2 was below average in the 17th and 18th centuries by a few ppm.

Oh, and according to the ice core data, at a certain level CO2 reaches saturation and becomes a negative or neutral feedback evidenced by falling temperature / rising CO2.

However, based on Antarctic ice core data, changes in CO2 follow changes in temperatures by about 600 to 1000 years, as illustrated in Figure 1 below.

The upper panel shows the air temperature at the summit of the Greenland Ice Sheet, reconstructed by Alley (2000) from GISP2 ice core daIce Sheet, reconstructed by Alley (2000) from GISP2 ice core daice core data.

For those not aware of the issue, ice core data, like that shown by Al Gore in An Inconvinient Truth, initially showed a very strong and compelling correlation between CO2 and temperature.

The reason is that by the time of the movie, better instrumentation and lab procedure had shown that temperature increases in the ice core data actually preceeded CO2 increases by 800 or more years.

Proxy data such as those generated from ice core samples, measurements of tree rings intervals, bore samples taken from sediments from the ocean and sea floor, and measurement of gases from bubbles trapped in ice are some examples of preserved physical characteristics of the past used by scientists to reconstruct prevailing climatic conditions in the past.

So far, by reading both CA and RC over a considerable period, much emphasis is placed on the atmosphere record contained in the ice cores, and on current (modern) instrument - recorded data.