Relative dating vs numerical dating What is the best free cyber sex text chat cell phone
A recent study (Van Hoof et al., 2005) demonstrated that the ice core CO2 data essentially represent a low-frequency, century to multi-century moving average of past atmospheric CO2 levels. A period where both methods consistently provide evidence for natural CO2 changes is during the 13th century AD. Highly variable Northern Hemisphere temperatures reconstructed from low- and high-resolution proxy data. The mean air age is thus aa = ai δa = ai Ts – Td where ages are dates A. Mixing of air from the ice sheet surface to the sealing depth is primarily by molecular diffusion.
It appears that the ice core data represent a long-term, low-frequency moving average of the atmospheric CO2 concentration; while the stomata yield a high frequency component. The results of the two independent methods differ significantly in the amplitude of the estimated CO2 changes (10 ppmv ice versus 34 ppmv stomatal frequency). doi:10.1073/pnas.0805721105 Mc Elwain et al., 2001. Stomatal evidence for a decline in atmospheric CO2 concentration during the Younger Dryas stadial: a comparison with Antarctic ice core records. The rate of air mixing by diffusion in the firn decreases as the density increases and the open porosity decreases with depth. (1996) determined the sealing depth at DE08 to be 72 m where the age of the ice is 40±1 years; at DE08-2 to be 72 m depth and 40 years; and at DSS to be 66 m depth and 68 years.
INTRODUCTION Anyone who has spent any amount of time reviewing climate science literature has probably seen variations of the following chart…
A record of atmospheric CO2 over the last 1,000 years constructed from Antarctic ice cores and the modern instrumental data from the Mauna Loa Observatory suggest that the pre-industrial atmospheric CO2 concentration was a relatively stable ~275ppmv up until the mid 19th Century.
Stomatal density can be empirically tested and calibrated to CO2 changes over the last 60 years in living plants. IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series #2004-013. Tom van Hoof on December 28, 2010 at am As one of the “stomata: people and author ofd the cited Tellus paper, I want to draw attention to one of the most interesting outcomes of our research. The natural source-sink ratio is far more variable than indicated by the ice cores.
The advantage to the stomatal data is that the relationship of the Stomatal Index and atmospheric CO2 can be empirically demonstrated… NOAA/NGDC Paleoclimatology Program, Boulder CO, USA. That is that for the past thousand years the stomata records seem to match with respect to timing to two Antarctic ice core records which are not often cited…. This was occurring long before man ever discovered how to burn things. 33–36…The discrepancies between the ice-core and stomatal reconstructions may partially be explained by varying age distributions of the air in the bubbles because of the enclosure time in the firn-ice transition zone.
GEOCARB GEOCARB provides a continuous long-term record of atmospheric CO2 changes; but it is a very low-frequency record… NOAA/NGDC Paleoclimatology Program, Boulder CO, USA. The lone fact that stomata data of the USA and Europe have the same timing of a CO2 wiggle which has also been recorded (but with a much lower amplitude) in two Antarctic ice cores is evidence enough that Co2 variability has been larger in the past millennium then assumed. […] Our results falsify the concept of relatively stabilized Holocene CO2 concentrations of 270 to 280 ppmv until the industrial revolution. The majority of the stomatal frequency-based estimates of CO 2 for the Holocene do not support the widely accepted concept of comparably stable CO2 concentrations throughout the past 11,500 years.
The lack of a long-term correlation between CO2 and temperature is very apparent when GEOCARB is compared to Veizer’s d18O-derived Phanerozoic temperature reconstruction. 2,000-Year Northern Hemisphere Temperature Reconstruction. IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series # 2005-019. If the variability would have been as small as the ice cores tell us, plant would hav e never ever picked this signal up on two different continents on another hemisphere. Atmospheric CO2 during the 13th century AD: reconciliation of data from ice core measurements and stomatal frequency analysis. SI-based CO2 reconstructions may even suggest that, during the early Holocene, atmospheric CO2 concentrations that were .300 ppmv could have been the rule rather than the exception. To address the critique that these stomatal frequency variations result from local environmental change or methodological insufficiencies, multiple stomatal frequency records were compared for three climatic key periods during the Holocene, namely the Preboreal oscillation, the 8.2 kyr cooling event and the Little Ice Age.
PLANT STOMATA Stomata are microscopic pores found in leaves and the stem epidermis of plants. The stomatal density in some C3 plants will vary inversely with the concentration of atmospheric CO2. Tom Van Hoof, an actual plant physiologist and author of numerous peer-reviewed papers on plant stomata made these comments… Stomata Notes Decadal- centennial- and millennial-scale fluctuations in atmospheric CO2 from 270-360 ppmv have been the norm throughout the Holocene.This model is derived from “geological, geochemical, biological, and climatological data.” The main drivers being tectonic activity, organic matter burial and continental rock weathering.ICE CORES The advantage to the ice core method is that it provides a continuous record of relative CO2 changes going back in time 800,000 years, with a resolution ranging from annual in the shallow section to multi-decadal in the deeper section. Carbon starvation in glacial trees recovered from the La Brea tar pits, southern California.According to the firn densification model, last year’s air is trapped at that depth in ice that was deposited over 2,000 years ago. Ice Core Resolution The so-called consensus will continue overestimating CO2 forcing until they accept the fact that ice core temperature estimates are at least an order of magnitude of higher resolution than ice core CO2 estimates. Ferdinand Engelbeen says: October 1, 2011 at am David Middleton says: September 30, 2011 at pm You can’t recover higher frequencies than you put into the ground.I have a lot of doubts about the accuracy of the FDM method. The ever-growing volume of peer-reviewed research on the relationship between plant stomata and CO2 will eventually force a paradigm shift. 33–36…The discrepancies between the ice-core and stomatal reconstructions may partially be explained by varying age distributions of the air in the bubbles because of the enclosure time in the firn-ice transition zone. The Nyquist frequency is equivalent to two-times the bubble enclosure period.
Search for relative dating vs numerical dating:
As can be seen in the figure above, plant stomata indicate a much greater range of CO2 variability; but are in general agreement with the lower frequency GEOCARB model. NOAA/NGDC Paleoclimatology Program, Boulder CO, USA. Esper, J., et al., 2003, Northern Hemisphere Extratropical Temperature Reconstruction, IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series # 2003-036. Tom van Hoof on December 28, 2010 at pm @ David Middleton… The ice cores cannot resolve CO2 shifts that occur over periods of time shorter than twice the bubble enclosure period. The assertion of a stable pre-industrial 270-280 ppmv is flat-out wrong. Stomatal evidence for a decline in atmospheric CO2 concentration during the Younger Dryas stadial: a comparison with Antarctic ice core records. The highly comparable fluctuations in the paleo-atmospheric CO2 records, which were obtained from different continents and plant species (deciduous angiosperms as well as conifers) using varying calibration approaches, provide strong evidence for the integrity of leaf-based CO2 quantification.