MSM3 Preparations for a third CSIRO meeting. / archived / read-only

 
  • Part of: Points on Climate Change
  • Introduction, Background and Conventions
    • CSIRO text is in green.
    • OneNation text is in red.
    • Senator Malcolm Roberts in his maiden speech asserted that CSIRO had no empirical evidence that human emissions of CO2 caused any significant global warming. Senator Roberts is a member of the One Nation Party.
    • 2016-09-26 CSIRO presentation in Sydney is here. The presentation and discussion were recorded and a transcript produced but there has not been agreement to release them.
    • 2016-11-01? OneNation technical response [interactive]
    • 2016-11-07 A wide ranging reply by Senator Roberts is [here as a pdf].
    • 2017-04-13 CSIRO Response is [here]. This document was undated with the stated date being assumed from within the meta data of the pdf file.
    • 2017-05-10 CSIRO Presentation here. The Minister for Science did not permit this meeting to be recorded. Minutes were taken but did not capture the discussion of scientific points.
    • 2017-07-29 OneNation Response here CSIRO repeated their presentation of 2017-05-10 as it had not been recorded. OneNation's response then followed, then discussions. This meeting was recorded and a transcript produced but there has been no agreement to release them.
      • Dr Peter Mayfield, Executive Director Environment, Energy and Resources, CSIRO (reports to CEO)
      • Dr Jack Steele, Director of Science Impacts Policy, CSIRO (reports to DCEO)
      • Dr Helen Cleugh, Director of the CSIRO Climate Science Centre (reports indirectly to Dr Mayfield)
      • Dr Steve Rintoul, CSIRO Fellow and Research Team Leader
      • 2017 07 26 or 29?
      • Peter Bobroff
      • Malcolm Roberts
      • Leon Ashby
      • Sean Black
      • https://www.csiro.au/~/media/About/Files/CSIRO-Leadership-Team-Chart.pdf
      • Kate Chapple, Advisor to Minister Sinodinos
      • Geoff Mason, Senior Advisor to Minister Sinodinos
    • 2017-08-09 CSIRO CEO letter responding to 2017-07-29 from OneNation.
    • This document is OneNations's response to this last CSIRO Letter
    • 2017-10-26 CSIRO CEO statement to Senate Estimates hearings.
    • This document is best read interactively online at: https://checkvist.com/checklists/627895 It is not currently open to the public.
  • Summary of One Nation's discussion with CSIRO
    • 2016-09-26 CSIRO gave a presentation in Sydney [link]. The presentation and discussion were recorded and a transcript produced but there has not been agreement to release them.
    • CSIRO were asked Is there anything that indicates impending danger? but evaded the question saying it was for the Australian people or perhaps for the Minister to answer.
    • The presentation initially covered many aspects of Australian climate but these have been replaced in subsequent discussions by What is unprecedented in the climate record of the last 10,000 years?
    • The most important topic was Evidence that humans have caused climate change which was covered in 6 points.
    • There have been 2 further meetings with CSIRO and 2 letters from CSIRO to the Minister for Science on the subject.
    • What is unprecedented in the climate record of the last 10,000 years? The claimed rate of temperature rise is based on only one data point.
      • Rate of rise in global mean temperature is unprecedented in past 10,000 years
        • 2017-05-10 CSIRO cited Marcott et al 2013. The paper's Supplementary Information contains a Gain Curve that indicates that the process used in the paper could not detect any event whose period was less than 300 years. This paper could not have detected any of the current trends (what ever they are) in the past 10,000 years.
        • Lead author Marcott himself admitted: the 20th century portion of our paleotemperature stack is not statistically robust, cannot be considered representative of global temperature changes From RealClimate
        • 2017-08-09 CSIRO cited Lecavalier et al 2017. The unprecedentedness reported in this paper relies on one data point in a short additional ice-core appended to 2 10,000 year ice-cores. The post 1830 segments of all three ice-cores are plotted at 1 year resolution while the 10,000 segments are plotted at 25 year resolution, often after Gaussian smoothing with 50 year sigma. No Gain Curve is given. The lead author supplied some requested information but not the raw data for the 2 long cores. This is not very strong evidence of unprecedented rates of temperature change.
        • 2017-08-09 CSIRO cited a chapter of the IPCC's Fifth Assessment report. One Nation is prepared to accept a quotation from a secondary source if it is backed up by a citation of a paper but not a broad reference to a whole chapter.
        • 2017-08-09 CSIRO cited the North Report. This is a secondary source whose conclusions are not relevant to unprecedented changes during the past 10,000 years.
        • 2017-08-09 CSIRO cited a Progress Article from the PAGES 2k Consortium (2013). While interesting, it was not relevant to unprecedented changes during the past 10,000 years. It contained the statement: Proxy records with negative correlation with temperature were inverted.
        • 2017-08-09 CSIRO cited a paper explaining the data collected by the PAGES2k Consortium (2017). The data is publicly available as stated and 581 proxies were downloaded for examination. Most spanned less than 1,000 years. Most proxies had a field labeled "QC Certification". We were a little surprised to see the authors of the proxy appearing in this QC field, on the few cases we checked. This paper is not relevant to unprecedented changes during the past 10,000 years.
      • Carbon dioxide concentrations in the atmosphere today are unprecedented over at least the past 800,000 years One Nation concedes that CO2 levels may now be unprecedented for 10,000 years but are still extremely low at 0.04%. CSIRO has not indicated that this level of CO2 is itself dangerous or detrimental. CO2 is not relevant to the human organism at low concentrations but the increased levels are of great benefit to plant organisms on which all life depends.
    • What evidence shows humans have caused climate change. No quantitative evidence has been provide that humans have caused X degrees of temperature change or Y watts/sq metre of flux change. No evidence has been provided to indicate dangerous levels of change in X or Y.
      • 1. Carbon dioxide is a greenhouse gas. OneNation agrees that carbon dioxide absorbs and emits long wave radiation
      • 2. Carbon dioxide concentrations in the atmosphere have increased. One Nation agrees that CO2 levels have increased slowly since 1850 and more rapidly since 1950.
      • 3. The extra carbon dioxide in the atmosphere comes from human activities. One Nation agrees that some of the extra CO2 could have come from human activities however the CSIRO reference to Land Sink data is strongly questioned and this has not been contested by CSIRO.
      • 4. part A. Less energy is leaving the top of the atmosphere in the wavelengths absorbed by carbon dioxide and other greenhouse gases. Perhaps it is but no quantitative evidence has been provided to indicate that it is significant.
        • 2017-07-26 CSIRO cited Harries 2001 One Nation's objections (below) have not been contested by CSIRO.
          • CSIRO cited Harries 2001 Fig 1c which does not show the empirical data measured by the satellites. It shows the component of the simulated spectrum (not defined) that includes only the effect of trace-gas changes between 1970 and 1997 (omitting temperature and humidity changes) to aid interpretation. CSIRO was misleading not to have labelled the graph as such. The satellites involved were quite dissimilar and were 27 years apart. The paper excluded the main absorption band of CO2 because it was "too noisy". Harries 2001 draws conclusions on the basis of two points 27 years apart. Any such implied trend is very dependent on the particular years chosen. No statistician would draw strong conclusions from 2 points arbitrarily chosen from a time series.
        • 2017-08-09 CSIRO cites Griggs, J. A.; Harries, J. E., 2007. This paper updates Harries 2001 but some of the objections to the original paper, which were uncontested, have not been addressed
        • 2017-08-09 CSIRO cites Chapman, D.; Nguyen, P.; Halem, M., 2013. This paper overcomes the objections to the Harries papers. It reports changes in trends of Radiance of the Outgoing Longwave radiation measured in hundredths of a degree Kelvin per year. Global, Tropical and Arctic results suggest decreasing trends. In order to assess the significance of these small changes in radiance we would have liked to spectrally integrate into watts/sq metre. The resolution of the published graphs was not up to the task. The lead author was not contactable and approaches through Dr Halem have not resulted in the required data. The significance of this paper is not clear to One Nation.
        • 2017-08-09 CSIRO shifts ground from outgoing longwave radiation at the top of the atmosphere to greenhouse effect of tropospheric ozone, citing Worden, H. M.; Bowman, K. W.; Worden, J. R.; et al., 2008
        • 2017-08-09 CSIRO shifts ground to energy at the earth surface not outgoing at top of atmosphere. This is a much more complex subject and less likely to yield definitive empirical evidence.
      • 4. part B. The additional carbon dioxide added to the atmosphere by human activities has enhanced the greenhouse effect. It may have done but no quantitative evidence has been provided that this enhancement is significant.
      • 5. The earth has warmed as a result of the enhanced greenhouse effect. One Nation considers this statement to be meaningless without quantification. One thousandth of a degree of warming is hardly dangerous.
      • 6. part A Observed changes in the climate system are consistent with an enhanced greenhouse effect. CSIRO has offered an opinion unsupported by any empirical evidence or cited papers.
      • 6. part B Other forcings (e.g. volcanoes, the sun, internal variability) cannot explain the magnitude, timing and distribution of observed trends. CSIRO has offered an opinion unsupported by any empirical evidence or cited papers.
    • One Nation's conclusion. CSIRO have not made even a prima facie that the current climate is unprecedented and dangerous or that humans are responsible for any specific amount of change.
  • OneNation: What is unprecedented in the climate record of the last 10,000 years?
    • CSIRO: Rate of rise in global mean temperature is unprecedented in past 10,000 years Marcott 2013
      • In relation to claims made in blog posts regarding the integrity of the Marcott study, and the questions raised regarding this research, it should be noted that there are currently 265 published papers in the peer-reviewed literature citing Marcott et al (2013), and there is no published study that draws the temperature reconstruction into question for the period for which sufficient proxies are available (~11,300 BP to 1800 CE).
      • The fact that 265 papers cite Marcott et all 2013 is irrelevant to veracity of the paper. It is likely that no more due diligence was done by any of the 265 than was done by CSIRO.
      • We further note that reference [1] derives a 12,000-year record of Arctic temperatures that extends to the year 2009 CE, with 25-year resolution, and concludes that the recent rate of Arctic temperature change is unprecedented in the entire Holocene.
        • Lecavalier B. S., et al. High Arctic Holocene temperature record from the Agassiz ice cap and Greenland ice sheet evolution, Proceedings of the National Academy of Sciences (2017). DOI: 10.1073/pnas.1616287114,
          • Vinther--Holocene thinning of the Greenland ice sheet
          • Fisher--Holocene climatic records from Agassiz Ice Cap,
          • Lecavalier--High Arctic Holocene temperature record from the Agassiz ice cap and Greenland ice sheet evolution
          • Data requested by emain 2017-08-15 Lecavalier
          • Data requested 2017-08-18 Lacelle

          • Benoit S. Lecavalier a,1 Not at Memorial University David A. Fisher b Not at Ottawa Glenn A. Milne b gamilne@uOttawa.ca Bo M. Vinther c bo@gfy.ku.dk Lev Tarasov a lev@mun.ca
            Philippe Huybrechts d No email on uni site Denis Lacelle e dlacelle@uOttawa.ca Brittany Main e Not at Ottawa James Zheng f james.zheng@canada.ca Jocelyne Bourgeois g Cant find company Arthur S. Dyke h,i Not at either uni

            a Department of Physics and Physical Oceanography, Memorial University, St. Johns, Canada, A1B 3X7; b Department of Earth and Environmental Sciences, University of Ottawa, Ottawa, Canada, K1N 6N5; c Centre for Ice and Climate, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark, 2100; d Earth System Science and Departement Geografie, Vrije Universiteit Brussel, Brussels, Belgium, 1050; e Department of Geography, University of Ottawa, Ottawa, Canada, K1N 6N5; f Geological Survey of Canada, Natural Resources Canada, Ottawa, Canada, K1A 0E8; g Consorminex Inc., Gatineau, Canada, J8R 3Y3; h Department of Earth Sciences, Dalhousie University, Halifax, Canada, B3H 4R2; i Department of Anthropology, McGill University, Montreal, Canada, H3A 2T7

          • Authors - IPCC relationships some IPCC authors and reviews. Possible skeptic
            • Benoit S. Lecavalier David A. Fisher AR5 Reviewer Glenn A. Milne AR5 Lead Author Bo M. Vinther Lev Tarasov AR5 Reviewer possible Contributing Author Philippe Huybrechts AR3 AR4 Contributing Author Denis Lacelle possible skeptic Brittany Main James Zheng Jocelyne Bourgeois Arthur S. Dyke
      • Agreed that there is one data point in the recent extension to the Agassiz ice cape series that can be interpreted as evidence for "an unprecedented rate of warming in the Holocene". This data point did not come from a calibrated recording thermometer sitting on the icecap but results from a complex set of measurements, models and assumptions each with its own unknowns and uncertainties.
        • (C) Rate of temperature change (black) based on the Gaussian filtered Agassiz temperature reconstruction. [img: screenshot-checkvist.com-2017-09-20-10-51-16.png] The red arrow indicates the one data point that is being interpreted as evidence for an unprecedented rate of warming in the Holocene.
        • The above graph has been reproduced from data supplied by the lead author and shows the first difference of Gaussian filtered( 50yr) for the full data set. This is to investigate different views and processes. [img: screenshot-localhost-2017-09-08-17-51-43.png] This plot extends some years beyond the chart from the paper and shows that the apparent rate of warming has already fallen below the "unprecedented" value.
        • Just viewing the post 1825 part of the above graph. Again it is first difference of Gaussian filtered( 50yr) for the data set, reproduced from files supplied by the lead author. [img: screenshot-localhost-2017-09-20-11-17-40.png]
          • Just post 1825 data but now removing the Gaussion filtering. It is now just first difference of the unfiltered data, calculated from files supplied by the lead author. [img: screenshot-localhost-2017-09-20-11-20-02.png] The red arrow shows the unprecedented data point. The 25 year sampling interval is obvious.
        • Lecavalier 2017 Fig S3 The post 1825 portion of the three cores involved, but at one year resolution. [img: screenshot--2017-09-07-17-57-40.png]
          • The short term variance of the 2009 core is recognisably different from the 1984 and 1987 cores. The processing of the 2009 core was not identical to the earlier cores which covered the bulk of the Holocene. The different processes may have had different gain curves so the rate comparisons may have been invalid.
          • Data extracted from the above chart Lecavalier 2013 Fig S3 [img: screenshot-localhost-2017-09-19-17-45-19.png]
          • First differences [img: screenshot-localhost-2017-09-19-17-47-33.png]
          • First differences of combined 1984 and 1987 series against 2009 series [img: screenshot-localhost-2017-09-19-18-42-52.png]
          • First differences (with Gaussian Filter sigma=1yr to cope with digitisation errors) [img: screenshot-localhost-2017-09-19-18-50-41.png]
          • First differences of combined 1984 and 1987 series against 2009 series (with Gaussian Filter sigma=1yr to cope with digitisation errors) [img: screenshot-localhost-2017-09-19-18-56-08.png]
          • There are periods where the differences between the 1984 and 1987 series exceed the "unprecedentedness" of the 2009 series.
        • In order to investigate this high resolution annual data it has been extracted from the previous graph image. This is not a perfect process. [img: screenshot-localhost-2017-09-20-11-48-11.png] The difference between the 1984 and 1987 datasets at about 1855 (blue) significantly exceeds the uniqueness of the 1990 spike (gold) which may just be measurement error.
        • First difference of unfiltered annual data. [img: screenshot-localhost-2017-09-20-11-35-31.png] The red arrow indicates the "unpredecented" rate of change.
        • First difference of Gaussian filtered (sigma 1yr) annual data. [img: screenshot-localhost-2017-09-20-11-41-03.png]
      • CSIRO reaffirms the scientific rigour of the Marcott et al. (2013) study and the conclusion that the rate of recent warming of global mean temperature is unprecedented in the past 10,000 years.
      • Your attention is drawn to the scientific rigour in Marcott 2013 Supplementary Materials where it is explained why waves of periods faster than 300 years could not be detected. It is the scientific rigour of CSIRO that is now being questioned.
        • 7. Sampling Resolution One question regarding potential smoothing of our global temperature stack is what effect the choice of time-step (20 yrs) used in this study has on our results. The average sampling resolution of the datasets is 160 years, the median is 120 years, and the full range spans from 20 to 500 years.
        • 9. Signal retention Numerous factors work to smooth away variability in the temperature stack. These include temporal resolution, age model uncertainty, and proxy temperature uncertainty. We conducted a synthetic data experiment to provide a simple, first-order quantification of the reduction in signal amplitude due to these factors......The gain function is near 1 above ~2000-year periods, suggesting that multi-millennial variability in the Holocene stack may be almost fully recorded. Below ~300-year periods, in contrast, the gain is near-zero, implying proxy record uncertainties completely remove centennial variability in the stack. Between these two periods, the gain function exhibits a steady ramp and crosses 0.5 at a period of ~1000 years.
        • [img: SI-Gain_curves.jpg] "The gain function is near 1 above ~2000-year periods, suggesting that multi-millennial variability in the Holocene stack may be almost fully recorded. Below ~300-year periods, in contrast, the gain is near-zero, implying proxy record uncertainties completely remove centennial variability in the stack. Between these two periods, the gain function exhibits a steady ramp and crosses 0.5 at a period of ~1000 years."
      • Studies published after Marcott et al. (2013), using a variety of data sets and analysis methods and covering various time periods, support the conclusion that recent rates of warming are unprecedented [e.g. 1-5].
          1. Lecavalier B. S., et al. High Arctic Holocene temperature record from the Agassiz ice cap and Greenland ice sheet evolution, Proceedings of the National Academy of Sciences (2017). DOI: 10.1073/pnas.1616287114,
          1. Masson-Delmotte, V., M. Schulz, A. Abe-Ouchi, J. Beer, A. Ganopolski, J.F. González Rouco, E. Jansen, K. Lambeck, J. Luterbacher, T. Naish, T. Osborn, B. Otto-Bliesner, T. Quinn, R. Ramesh, M. Rojas, X. Shao and A. Timmermann, 2013: Information from Paleoclimate Archives. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, US,
          1. North, Gerald R.; Biondi, Franco; Bloomfield, Peter; Christy, John R.; Cuffey, Kurt M.; Dickinson, Robert E.; Druffel, Ellen R. M.; Nychka, Douglas; Otto-Bliesner, B.; Roberts, N.; Turekian, K.; Wallace, J. (22 June 2006), Surface temperature reconstructions for the last 2,000 years, Washington, D.C.: National Academies Press, ISBN 0-309-10225-1. (data publicly available at https://www.ncdc.noaa.gov/paleo-search/study/14188)
          1. PAGES 2k Consortium (2013). Continental-scale temperature variability during the past two millennia. Nature Geoscience, Vol. 6, pp. 339-346 (data publicly available at https://www.ncdc.noaa.gov/paleo-search/study/14188)
          • PAGES2k at ClimateAudit
          • PAGES2k QC certification can be done by the lead author of the paper.
          • There are 34 associated people in a group that have contributed 371 series, mostly tree rings.
          • There is another group of 6 people who have contributed 118 series, nearly all tree rings.
          1. PAGES2k Consortium (2017). A global multiproxy database for temperature reconstructions of the Common Era, Scientific Data 4, Article number: 170088 (2017) doi:10.1038/sdata.2017.88
      • The conclusion drawn by CSIRO and by the Marcott study is based on a comparison of recent temperatures as measured by instruments to past temperatures inferred from proxy data. Neither Marcott, nor CSIRO, make any conclusions based on the “uptick” part of the temperature record.
      • This approach is used because the best information we have about recent temperatures are those made by instruments measuring temperature (thermometers measure temperature more accurately than tree rings, ice cores, or plankton preserved in sediments).
      • There is no scientific evidence in any other climate variable to support the supposition that there may have been periods of rapid warming and cooling in the past that were missed by Marcott’s reconstruction method, nor has a plausible physical mechanism been identified that could have driven such spikes in warming and cooling. In addition, it can be demonstrated that the Marcott method could have detected periods of rapid warming/cooling in the past, had they occurred.
  • OneNation: What proves it is caused by carbon dioxide from human activity?
    1. Harries et al. (Nature, 2001)
    • CSIRO reaffirms its conclusion that changes in radiative spectra provide direct empirical evidence of an enhanced greenhouse effect.
    • Studies published since 2001 confirm that less energy is leaving the top of the atmosphere in the wavelengths absorbed by carbon dioxide and other greenhouse gases [e.g. 6-8],
        1. Chapman, D.; Nguyen, P.; Halem, M., 2013. A decade of measured greenhouse forcings from AIRS. Proc. SPIE, 8743, 874313.
        • Data requested from Dr Halem 2017-08-18
        • Increased greenhouse gasses reduce the transmission of Outgoing Longwave Radiation (OLR) to space along spectral absorption lines eventually causing the Earth’s temperature to rise in order to preserve energy equilibrium. This greenhouse forcing effect can be directly observed in the Outgoing Longwave Spectra (OLS) from space-borne infrared instruments with sufficiently high resolving power 3, 8. In 2001, Harries et. al observed significant increases in greenhouse forcings by direct inter-comparison of the IRIS spectra 1970 and the IMG spectra 19978. We have extended this effort by measuring the annual rate of change of AIRS all-sky Outgoing Longwave Spectra (OLS) with respect to greenhouse forcings. Our calculations make use of a 2°x2° degree monthly gridded Brightness Temperature (BT) product. Decadal trends for AIRS spectra from 2002-2012 indicate continued decrease of -0.06 K/yr in the trend of CO2 BT (700cm-1 and 2250cm-1), a decrease of -0.04 K/yr of O3 BT (1050 cm-1), and a decrease of -0.03 K/yr of the CH4 BT (1300cm-1). Observed decreases in BT trends are expected due to ten years of increased greenhouse gasses even though global surface temperatures have not risen substantially over the last decade.
        • https://sci-hub.cc/10.1117/12.2017019
        • A decade of measured greenhouse forcings from AIRS
        1. Griggs, J. A.; Harries, J. E., 2007. Comparison of spectrally resolved outgoing longwave radiation over the tropical Pacific between 1970 and 2003 using IRIS, IMG, and AIRS. Journal of Climate, 20, 3982-4001.
        • The observation of changes in the earth’s spectrally resolved outgoing longwave radiation (OLR) provides a direct method of determining changes in the radiative forcing of the climate system. An earlier study showed that satellite-observed changes in the clear-sky outgoing longwave spectrum between 1997 and 1970 from the Infrared Interferometer Spectrometer (IRIS) and Interferometic Monitor of Greenhouse Gases (IMG) instruments could be related to changes in greenhouse gas composition. The authors present a new study that extends this to 2003, through the first use of a new, independent source of global atmospheric infrared spectra, from the Atmospheric Infrared Sounder (AIRS) experiment. AIRS is a dispersion grating spectrometer, while the other two were Fourier transform spectrometers, and this is taken into account in the analysis. The observed difference spectrum between the years 2003 and 1970 generally shows the signatures of greenhouse gas forcing, and also shows the sensitivity of the signatures to interannual variations in temperature. The new 2003 data support the conclusions found in the earlier work, though, interestingly, the methane (CH4) Q branch centered at 1304 cm−1 exhibits more complex behavior, showing a decrease in intensity in the difference spectrum between 1997 and 2003. Sensitivity analysis indicates that this is due to changes in temperature structure, superposed on an underlying increase in CH4. Radiative transfer calculations based on reanalysis data are used to simulate the changes in the OLR spectrum; limitations in such data and possible variations that could account for several observed effects are discussed.
        • Comparison of Spectrally Resolved Outgoing Longwave Radiation over the Tropical Pacific between 1970 and 2003 Using IRIS, IMG, and AIRS: Journal of Climate: Vol 20, No 15
        1. Worden, H. M.; Bowman, K. W.; Worden, J. R.; et al., 2008. Satellite measurements of the clear-sky greenhouse effect from tropospheric ozone. Nature Geoscience, 1, 305-308.
        • SIDE ISSUE: Ozone may be a greenhouse gas but surely CO2 is the only greenhouse gas whose emission by humans is under discussion.
        • Radiative forcing from anthropogenic ozone in the troposphere is an important factor in climate change1, with an average value of 0.35 W m- 2 according to the Intergovernmental Panel for Climate Change1 (IPCC). IPCC model results range from 0.25 to 0.65 W m- 2, owing to uncertainties in the estimates of pre-industrial concentrations of tropospheric ozone1, 2, 3, and in the present spatial and temporal distributions of tropospheric ozone4, 5, 6, 7, 8, which are much more variable than those of longer-lived greenhouse gases such as carbon dioxide. Here, we analyse spectrally resolved measurements of infrared radiance from the Tropospheric Emission Spectrometer9 on board the NASA Aura satellite, as well as corresponding estimates of atmospheric ozone and water vapour, to obtain the reduction in clear-sky outgoing long-wave radiation due to ozone in the upper troposphere over the oceans. Accounting for sea surface temperature, we calculate an average reduction in clear-sky outgoing long-wave radiation for the year 2006 of 0.480.14 W m- 2 between 45° S and 45° N. This estimate of the clear-sky greenhouse effect from tropospheric ozone provides a critical observational constraint for ozone radiative forcing used in climate model predictions.
        • WordenSatellite2008.pdf
    • and more energy is reaching the surface in these wavelengths [e.g. 9-10]. These measurements provide further direct empirical evidence of the enhanced greenhouse effect.
      • NEW SUBJECT: Energy at the earth surface not outgoing at top of atmosphere.
        1. Philipona, R; Durr, B; Marty, C; et al., 2004. Radiative forcing - measured at Earth's surface - corroborate the increasing greenhouse effect. Geophysical Research Letters, 31, L03202.
        • The Intergovernmental Panel for Climate Change (IPCC) confirmed concentrations of atmospheric greenhouse gases and radiative forcing to increase as a result of human activities. Nevertheless, changes in radiative forcing related to increasing greenhouse gas concentrations could not be experimentally detected at Earth’s surface so far. Here we show that atmospheric longwave downward radiation significantly increased (+5.2(2.2) Wm-2) partly due to increased cloud amount (+1.0(2.8) Wm-2) over eight years of measurements at eight radiation stations distributed over the central Alps. Model calculations show the cloud-free longwave flux increase (+4.2(1.9) Wm-2) to be in due proportion with temperature (+0.82(0.41) oC) and absolute humidity (+0.21(0.10) g m-3) increases, but three times larger than expected from anthropogenic greenhouse gases. However, after subtracting for two thirds of temperature and humidity rises, the increase of cloud-free longwave downward radiation (+1.8(0.8) Wm-2) remains statistically significant and demonstrates radiative forcing due to an enhanced greenhouse effect.
        • Radiative forcing - measured at Earth's surface - corroborate the increasing greenhouse effect - Philipona - 2004 - Geophysical Research Letters - Wiley Online Library
        1. Feldman, D. R., W. D. Collins, P. J. Gero, M. S. Torn, E. J. Mlawer & T. R. Shippert , 2015. Observational determination of surface radiative forcing by CO2 from 2000 to 2010. Nature, 519, 339–343, doi:10.1038/nature14240.
        • The climatic impact of CO2 and other greenhouse gases is usually quantified in terms of radiative forcing1, calculated as the difference between estimates of the Earth’s radiation field from pre-industrial and present day concentrations of these gases. Radiative transfer models calculate that the increase in CO2 since 1750 corresponds to a global annual mean radiative forcing at the tropopause of 1.8 ± 0.19 W m-2 (ref. 2). However, despite widespread scientific discussion and modelling of the climate impacts of well-mixed greenhouse gases, there is little direct observational evidence of the radiative impact of increasing atmospheric CO2. Here we present observationally based evidence of clear-sky CO2 surface radiative forcing that is directly attributable to the increase, between 2000 and 2010, of 22 parts per million atmospheric CO2. The time series of this forcing at the two locations—the Southern Great Plains and the North Slope of Alaska—are derived from Atmospheric Emitted Radiance Interferometer spectra3 together with ancillary measurements and thoroughly corroborated radiative transfer calculations4. The time series both show statistically significant trends of 0.2 W m-2 per decade (with respective uncertainties of ±0.06 W m-2 per decade and ±0.07 W m-2 per decade) and have seasonal ranges of 0.1–0.2 W m-2. This is approximately ten per cent of the trend in downwelling longwave radiation5–7. These results confirm theoretical predictions of the atmospheric greenhouse effect due to anthropogenic emissions, and provide empirical evidence of how rising CO2 levels, mediated by temporal variations due to photosynthesis and respiration, are affecting the surface energy balance.
    • The more recent studies confirm and extend the conclusion reached by Harries et al. (2001). These studies use new data sets and methods that are not subject to limitations noted by the original Harries et al. study. Specifically, the new studies use improved instruments and satellites, span the spectral range of the main CO2 absorption band, and most are based on continuous measurements from single instruments (satellite or ground-based), which avoids introducing uncertainties or errors that might potentially arise as a result of intercalibrations between different sensors/satellites.
    1. Mann, Bradley and Hughes (1998)
    • Senator Roberts referred to a paper published two decades ago by Mann et al. (1998). This study was not used by CSIRO in its briefing and is not relevant to the present discussion.
    • Highlighting available data sets of global mean surface temperatures in the late 20th – early 21st century
    • Over the past twenty years, multiple studies have used a variety of methods and data sets to reconstruct past temperatures over various time periods. These studies have consistently shown that global mean surface temperatures in the late 20th – early 21st century are unusual in the context of the past 1000 years (the period covered by Mann et al., 1998). The data sets underpinning these studies are publicly available [5].
    • Based on an assessment of the published literature available by 2013, reference [2] concluded “For average annual NH temperatures, the period 1983–2012 was very likely the warmest 30-year period of the last 800 years (high confidence) and likely the warmest 30-year period of the last 1400 years (medium confidence).”
  • Agreed. This study was not used by CSIRO in its briefing and is not relevant to the present discussion.
  • Parked reference material
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Send an email to yourself and add the sender to Contacts for future use.

  • The email subject becomes the list item's text.
  • The email body becomes the list item's note.
  • All attachments from the email are attached to the list item (PRO only).
  • In the subject, you can also add #tags, ^due dates, and @assignees with Checkvist's smart syntax.

You can also set up voice integration on mobile devices