Crux of a Core, Part 1 – addressing J Storrs Hall Posted on 26 February by Rob Honeycutt Over the past couple of years perusing the internet on climate issues I have repeatedly come upon various misrepresentations of the GISP2 ice core record here and here and here and here and here and here and here and here and here. I could literally list at least a more locations where I find this exact same argument on the internet. Each misrepresentation misses the very basic point that an ice core – any ice core or any other proxy – is a local record of temperature. Using a single ice core record as a proxy for global temperature is a little like reading the thermometer on your back porch and claiming you know the global average temperature. One of the major challenges in today’s world is that misinformation pops up and propagates like rabid bunnies before the scientific community can effectively address the erroneous information. The original source of this specific misinformation seems to come from J Storrs Hall, a nano technology engineer from the Foresight Institute. When this blog post hit the internet it quickly made the rounds to all the popular climate skeptic blogs and is now a permanent resident of the “interweb” and continues to misinform people. Let’s get to the crux of this core.
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Advanced Search Abstract Oscillations in the time series of insoluble microparticle characteristics between 0. Elevated values in microparticle number and mass, especially during the Younger Dryas, are related to Northern Hemisphere aridity and the subsequent increase in dust available for long-range transport to Greenland. This scenario occurs with the colder climatic conditions that result from a more expanded spatially and temporally polar vortex.
Peaks in mean grain size based on number mean number diameter are a proxy for increased strength in zonal winds westerlies. Highs in mean number diameter in the earlier part of the record often coincide with number and mass peaks reflecting the increased temperature and pressure gradients with an expanded polar vortex.
ABSTRACT. The rare melt feature in the GISP2, central Greenland deep ice core have decreased in frequency over the most recent years. Calibration of this temperature change during the Holocene. METHODS The GISP2 ice core was drilled during the summers of (the upper m of the core) is shown in Figure I, ALII!)’ al/d.
The Earth’s Climatic History on Ice Paleoclimatologists are concerned with the cycle of glacials and interglacials that have occurred throughout Earth’s history. The variety of factors contributing to the climatic system results in complexities that are difficult to unravel. Ice core geochemistry has been instrumental in the quest for an understanding of Earth’s climatic past. Researcher Mary Davis examines a thick layer of dust inside an ice core taken from Mt.
Kilimanjaro in Tanzania, Africa. The dust layer signifies a major drought event that struck the region in the past. Thompson, Ohio State University. Ice core analysis is a fairly new science; the first deep cores were drilled in the s.
Holocene climatic optimum
Produced a series of Summer seasonal maps. Project COHMAP Cooperative Holocene Mapping Project dev in s compared simulations of LGM climates from models with proxy climate data fossil pollen Pollen is used as a indicated of continental climates – pollens are carried by wind, water and insects and provides insight into the plants that are growing at a particular time. Use climate output to narrow range of possible vegetation types 3. Run biome model biomes reflect plant communities to allow vegetation to compete for resources 4.
Holocene Climate An interglacial period experiencing general warm and wet conditions. There have been a number of important shifts in climate during this time; stronger, then weaker monsoon 10, – 8, yrs ago monsoon activity in africa was much stronger higher rainfall – lake full conditions in sahara desert, greater extent northward of Sahel grasslands this reflects precessional control of monsoon activity.
A synchronized dating of three Greenland ice cores throughout the Holocene B. M. Vinther,1 H. B. Clausen,1 S. J. Johnsen,1 S. O. Rasmussen,1 K. K. Andersen,1 extend the DYE-3 Holocene record. The new synchronized dating relies heavily on this record of 75, stable isotope samples. The dating of the early Holocene consists of.
The Medieval Warm Period MWP until about CE displays generally moist and warm climate conditions with minor fluctuations [stability], likely in response to variations in summer monsoon intensity. The three-partite period of the Little Ice Age LIA , shows hydrologically unstable conditions between and CE with remarkably colder periods, assigned to a prolonged seasonal ice cover.
The strengthened solar activity could be significantly amplified by the variations in ultraviolet radiation as well as clouds e. The model computes a new Dalton-type sunspot minimum from approximately to and a new Dalton-type period TSI minimum from approximately to Periods with many sunspots are associated with high solar activity and warm climate periods.
The conclusion is that the activity level of the Modern Maximum — is a relatively rare event, with the previous similarly high levels of solar activity observed 4 and 8 millennia ago Usoskin et al.
Originally published in Journal of Creation 16, no 1 April The differences between the two paradigms also show up in the interpretation of the Ice Age portion of the cores. Large changes in oxygen isotope ratio are interpreted by uniformitarian scientists as wild fluctuations in temperature in the North Atlantic region. Uniformitarian scientists are still perplexed over the huge Ice Age fluctuations.
The Greenland Ice Core Chronology , GICC05, is extended back to 42ka b2k (before AD), i.e. to the end of Greenland Stadial The chronology is based on independent multi-parameter counting of annual layers using comprehensive high-resolution.
Here, we investigate the regional footprints of the North Atlantic weather regimes on Greenland isotope and climate variability, using a compilation of 22 different shallow ice-cores and the atmospheric pressure conditions from the twentieth century reanalysis 20CR. Likewise, the Scandinavian blocking and the Atlantic ridge also show remarkable imprints on isotopic composition over the region.
To assess the robustness and model dependency of our findings, a second isotope simulation from the isotopic model is also explored. This study opens the possibility for reconstructing past changes in the frequencies of occurrence of the weather regimes, which would rely on the sensitive regions identified here, and the use of additional proxies over the North Atlantic region. We would also like to thank two anonymous reviewers for their constructive comments that helped to improve the final version of the manuscript.
J Geophys Res Geophys Res Lett Mon Weather Rev Q J R Meteorol Soc Bull Am Meteorol Soc J Geophys Res —
But the planet bears the scars of only a few hundred of these impacts because of weathering processes like erosion. Through analysis of crater size and sediments from the crater, they estimate that the asteroid that slammed into Earth was more than a kilometer in diameter, composed mainly of iron. This discovery suggests that Earth may harbor more signs of its tumultuous history beneath its glaciers and ice sheets.
They were using archival measurements of the Greenland Ice Sheet to study its ice flows and underlying bedrock.
The Holocene RCCs are also characterized by peaks in the sea-salt [Na+] series from the GISP2 ice core (Figure 1). These sea-salt [Na+] variations closely reflect the intensity of the Icelandic Low (Meeker and Mayewski, ).
Climate at the core: Amy Dusto Like a prehistoric fly trapped in amber during dinosaurs’ days, airborne relics of Earth’s earlier climate—including dust, air bubbles, sea salts, volcanic ash, and soot from forest fires—can end up trapped in glacial ice for eons. To climate scientists, those relics tell a story about how our planet’s climate and atmosphere have changed over thousands of years.
The embedded pebbles and dingy ice tell researchers that this portion of the ice core is from the bottom of the glacier, right above bedrock. This chunk comes from the first ice core drilled at Mt. Hunter, Alaska; the core’s total length was feet. Photo by Mike Waszkiewicz. What they find out could have an impact on worldwide civilization within a few generations—especially in coastal regions.
Crux of a Core, Part 1
Evidence[ edit ] The best evidence for Dansgaard—Oeschger events remains in the Greenland ice cores , which only go back to the end of the last interglacial, the Eemian interglacial. Ice core evidence from Antarctic cores suggests that the Dansgaard—Oeschger events are related to the so-called Antarctic Isotope Maxima by means of a coupling of the climate of the two hemispheres, the Bi-polar Seesaw.
Unfortunately, current ice core records from Greenland extend only through the last most recent glacial period so direct evidence of D-O events in earlier glacial periods from Greenland ice is unavailable. However, work by Stephen Barker and colleagues has shown that the existing Greenland record can be reconstructed by deriving the Antarctic ice core record. This allows for the reconstruction of an older Greenland record through the derivation of the nearly million-year-long Antarctic ice core record.
Heinrich events only occur in the cold spells immediately preceding D-O warmings, leading some to suggest that D-O cycles may cause the events, or at least constrain their timing.
Holocene data from Greenland ice core GISP2 (d) show little variability in air temperature over Greenland (δ 18 O ice data in red), except during the ka event, and greater variability in sea salt Na concentration (black) at that and other times, such as the Little Ice Age (after ref. 1).
Their data indicated that after the termination of the glacial period, temperatures steadily rose to a maximum of 2. After the Little Ice Age, they report that temperatures once again rose, but that they had “decreased during the last decades,” thereby indicating that the MWP in this part of the Arctic was significantly warmer than it was just before the turn of the century.
Wagner and Melles also worked on Greenland, where they extracted a 3. Key to the study were biogeochemical data, which, in the words of the two researchers, reflect “variations in seabird breeding colonies in the catchment which influence nutrient and cadmium supply to the lake. And after that “medieval warm period,” their data suggested another absence of birds during what they called “a subsequent Little Ice Age,” which they said was “the coldest period since the early Holocene in East Greenland.
However, values of the most recent measurements of seabird numbers were not as great as those inferred for the earlier Medieval Warm Period, which result indicates that higher temperatures prevailed during much of the period from to years BP than those that had been observed over the most recent hundred years. A third Greenland study was conducted by Kaplan et al. This work revealed that the interval from to years BP was marked by warmth and stability, but that the climate cooled thereafter until its culmination in the Little Ice Age.
From years BP, however, there was a partial amelioration during the Medieval Warm Period, which was associated with an approximate 1. In a non-Greenland Arctic study, Jiang et al. Starting from a maximum value of about 8. Hence, their data clearly showed that the Medieval Warm Period in this part of the Arctic was significantly warmer than it is there now. Moving on, Moore et al. Over the entire period from AD , temperatures averaged 2.
Detecting Holocene changes in thermohaline circulation
Paleoclimate Overview SUMMARY The task of understanding climate change and predicting future change would be complex enough if only natural forcing mechanisms were involved. It is significantly more daunting because of the introduction of anthropogenic forcing and even more so considering the limitations in available records. In effect, the paleoclimate record provides a series of cases and lessons upon which our understanding of climate change can be constructed and tested.
The paleo perspective has provided some significant surprises concerning climate change, changes in atmospheric chemistry, and the response of natural systems to climate change. Perhaps most surprising is the demonstration that these rapid climate change events turn on and off in decades or less and may last centuries to millennia. Research Pathways for the Next Decade.
Stable isotopes and climate history from polar ice cores-Stable isotopes of oxygen and hydrogen and their use in ice core studies-Paleoclimate studies on Greenland ice cores over the last 40 years-Antarctic records of climate history-Correlation of Greenland and Antarctic recordsUH Winter School Talk # 26 Thorsteinn Thorsteinsson.
Global effects[ edit ] Temperature variations during the Holocene from a collection of different reconstructions and their average. The most recent period is on the right, but the recent warming is not shown on the graph. At 16 sites, where quantitative estimates have been obtained, local HTM temperatures were on average 1. Northwestern North America had peak warmth first, from 11, to 9, years ago, and the Laurentide ice sheet still chilled the continent.
Northeastern North America experienced peak warming 4, years later. This was caused by a strengthening of the African monsoon by changes in summer radiation, resulting from long-term variations in the Earth’s orbit around the Sun. The ” Green Sahara ” was dotted with numerous lakes, containing typical African lake crocodile and hippopotamus fauna. A curious discovery from the marine sediments is that the transitions into and out of the wet period occurred within decades, not the previously-thought extended periods.
This introduction contributed to the rapid transition to the arid conditions found in many locations in the Sahara. However, some authors have used the term “Holocene Climatic Optimum” to describe the earlier southern warm period, as well. Comparison of ice cores[ edit ] A comparison of the delta profiles at Byrd Station , West Antarctica m ice core recovered, and Camp Century , Northwest Greenland, shows the post glacial climatic optimum.
A similar comparison is evident between the Dye 3 and Camp Century cores regarding this period. The ice core contained distinct melt layers all the way to bedrock indicating that Hans Tausen Iskappe contains no ice from the last glaciation; i.
Enormous Impact Crater Spotted in Greenland Under Glacial Ice
Previous Next Measurements with modern instruments the instrumental record are available only for roughly the past century. This is insufficient to describe the full natural variability of the climate system, which makes attribution of observed changes difficult. We want to know if the changes observed in the recent past are unusual compared to pre-industrial climate variability. If they are it is more likely that they are anthropogenic , if not they could well be natural.
Figure 15 shows the EPICA ice core CO 2 concentration and air temperature for the most recent 20 years, which is within the last ice age. The temperature scale shows the difference from the average temperature of the last years, so 0 °C is no change from today’s climate.
For a—e, the dashed red curve is the calcium carbonate content at the respective sub cores of BC after It was necessary to switch to the more sensitive Finnigan for the stable isotope analyses in the LIA samples where the benthic foram abundance was minimal because of higher clay and silt fluxes. Isotopic results show good agreement between the two instruments see Fig. If these data accurately reflect bottom water nutrient levels, then during the LIA NADW was nearly completely replaced by nutrient-rich circumpolar water in the deep western North Atlantic.
This increase is driven by samples in only the upper 2 cm of the cores, and is markedly less than what would be expected from a 0. The two tracers cannot both be reflecting deep ocean nutrient levels accurately. Although neither proxy is perfect, we do not presently have enough information to determine which is more reliable. Box core tops are sometimes disturbed in the recovery process, and the core is bioturbated, but those processes should influence the trace metal and isotopic data equally.
Carbon isotope ratios are also known to be influenced by the rain rate of organic carbon 29 , 30 , but those problems are thought to be of greatest concern in upwelling regions, not the centers of subtropical circulation like the Sargasso Sea. If we were to calculate the mass accumulation rate of organic carbon, there would be a large spike during the LIA because the rate of sedimentation spikes 20 , but that artifact would not be preserved in the sedimentary record as the percent organic carbon decreases to a steady state value.
One test of our Bermuda Rise observations is to study shallower locations where the potential for carbonate dissolution is not so great. Unfortunately, at present only a few open marine locations are known to resolve the LIA, and shallower sites might not be as sensitive to changes in the densest components of NADW.
Location map and Agassiz proxy temperature records: A Map showing the study area with the names and locations of ice core borehole sites mentioned in the text. Each record is referenced to its preindustrial temperature value at CE. The two time series were remarkably similar, leading the authors to adopt a spatially homogeneous change in air temperature across the region spanned by these two ice caps.
These so-called thinning curves provide a valuable constraint on model reconstructions of the Greenland ice sheet 5.
Two ice-core d18 O records from Svalbard illustrating climate and sea-ice variability suggest that the ice core nearly reached the bottom. Dating with a glaciological flow model (Nye, ), using the The Austfonna ice core During the spring of a m-deep core was drilled on the.
From this was recovered the deepest ice core record to date. Comparative data between these two deep cores have allowed scientists to develop an ice core-derived paleoenvironmental record dating back greater than , years BP BP means “before present” and “BP” is defined as In other words, the ice has been confirmed to be as old as the collective measurements indicate. These data alone destroy the core doctrine of the theory of Young Earth Creationism that the Earth is only about 6, years old.
In addition to the actual age of the ice at any given depth in the core, scientists can also determine the mean temperature of the Earth’s past climate for different times and ages by measuring the ratio of the isotopes of oxygen O16 and O18 gas present in the CO2. Secular critics of Young Earth Creationism cite the very existence of the Greenland Ice Sheet and the paleoenvironmental record it contains as well as the data found in ice cores from the glaciers on Kilimanjaro in Africa and Huascaran in Peru as absolute proof that the Earth is older than 6, years and that Noah’s flood did not occur, since there are no indications of a flood in the ice core layers.
On the first point they are absolutely correct. On the second point, we disagree that the lack of direct evidence in the ice proves that a global flood did not take place at all. There is certainly much “indirect” evidence to consider. The ice core records, whether in Greenland or mountain top glaciers around the globe, are replete with “melt” indicators.