While ramping up his own invective to fit as much ad hominem as possible into a single sentence:
Mr. Sauer parroted baseless talking points that have their origin in fossil-fuel industry-funded climate change denial propaganda, not honest scientific discourse.
Michael Mann says:
“overall warmth of the globe and northern hemisphere today is substantially greater than during Medieval time”
Except, there’s that pesky ice core proxy temperature data (proxy temperature data is something Mann embraces for his own Hockey Stick) that says otherwise:
And he finishes up with this gem:
Readers interested in the truth behind the science, rather than the falsehoods and smears perpetuated by uninformed individuals like Mr. Sauer, should consult scientist-run websites like skepticalscience.com, or books on the topic like my own “Dire Predictions: Understanding Climate Change”. Let’s get past the fake debate about whether the problem exists, and on to the worthy debate about what to do about it.
Last I heard, skepticalscience.com was run by a cartoonist.
Having the courage to “do nothing” is also worthy of debate.
[Added] Given his quote, Dr. Mann might find the recent change in the AP style book interesting.
Update: Some people had questions about the graph and it’s representivity. For that, we cite the paper by Dr. Richard B. Alley, of Penn State, a colleague of Mann and a vociferous climate change proponent, much like Dr. Mann himself. The bolding in the abstract is mine.
The Younger Dryas cold interval as viewed from central Greenland
Quaternary Science Reviews
Volume 19, Issues 1-5, 1 January 2000, Pages 213-226.
Richard B. Alley
Department of Geosciences and Environment Institute, The Pennsylvania State University, Deike Building, University Park, PA 16802, USA
Greenland ice-core records provide an exceptionally clear picture of many aspects of abrupt climate changes, and particularly of those associated with the Younger Dryas event, as reviewed here. Well-preserved annual layers can be counted confidently, with only ~1% errors for the age of the end of the Younger Dryas ~11,500 years before present. Ice-flow corrections allow reconstruction of snow accumulation rates over tens of thousands of years with little additional uncertainty. Glaciochemical and particulate data record atmospheric-loading changes with little uncertainty introduced by changes in snow accumulation. Confident paleothermometry is provided by site-specific calibrations using ice-isotopic ratios, borehole temperatures, and gas-isotopic ratios. Near-simultaneous changes in ice-core paleoclimatic indicators of local, regional, and more-widespread climate conditions demonstrate that much of the Earth experienced abrupt climate changes synchronous with Greenland within thirty years or less. Post-Younger Dryas changes have not duplicated the size, extent and rapidity of these paleoclimatic changes.
Source data for the graph: ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/gisp2/isotopes/gisp2_temp_accum_alley2000.txt
UPDATE2: In pointing out an error I made (in comments) about the end date in the GISP2 graph above (ending 95 years before present) Nick Stokes reminded me of a detailed analysis I did in 2009 showing the scale of Mann’s Hockey stick relative to the GISP2 data.
The graph from that post, shown above, illustrates the last
3000 5000 years, with the 20th century instrumental record splice added (like Mann did in his original hockey stick paper) to show the warming of the last century. Clearly, the medieval warm period around the year 1000 is still warmer than the present
And there is a video, which illustrates the scale of the “hockey stick” compared to the warmer periods of the past: