IPCC: Last 30-year period warmest of last 800 years

So why was it so warm 800 years ago?

The Washington Post reports:

The latest review of climate science from the Intergovernmental Panel on Climate Change (IPCC), though not finalized, is making the rounds. The prevailing headline is that the panel is more certain than ever that most of the warming observed in recent decades is human-caused. It’s level of certainty has increased from at least 90 percent in 2007 to at least 95 percent in the new report.

Officials from the IPCC stress that the leaked draft is not its final product. A government review is ongoing, so some of the conclusions may be altered. But here are some of the more interesting preliminary findings…

Read more…

10 thoughts on “IPCC: Last 30-year period warmest of last 800 years”

  1. My question is how do they know that there have been no 30-year periods that were warmer than the last 30-year period. Paleo temperature estimates usually provide 100-year estimates do they not? How can IPCC compare 30-year thermometer estimates to 100-year paleo estimates when no one else knows how to do that?

  2. Snorbert is right, certainly.
    Moreover, if temps over the last 30 years are warmer than anything during the last 800 years, and if 2010-800=1230, then we’re in the Medieval Warm Period, which has been variously reported as global, European, or one pasture in Kent and has been reported variously as about as warm, cooler than, or warmer than now.
    The last 30 years encompasses a period just after an Ice Age scare, rising temps to about 1996 or 1998, and level to cooling temps since then. We’ve had level-to-cooling temperatures about as long as we had rising temperatures, according to the various boffins who have reported various measurements.
    Why do I find all of this pretty thin as the basis for guessing what will happen over the next ten years, let alone hundred?

  3. there you go again, Milloy, pointing out where the mystery is not a mystery at all. Talking history or, as us sophisticates regard it—the discipline called paleoclimatology—where Mann plyed fast and loose with the surrogate tree rings and such.

    in fact, my favorite warm period was the Minoan, which I didn’t know about until I saw the Russian paleoclimate insect study that used insect carcasses for a surrogate of temps—and they included the Roman and the Minoan and if you say Minoan it sounds so Classical. so we got the minoan warm 2700 years ago, the roman 1700 years ago, the medieval 900 years ago.

    Hey Fred, I wanna see your next paper include the Minoan. sounds so cool but its still warm.

    John Dale Dunn MD JD Consultant Emergency Services/Peer Review Civilian Faculty, Emergency Medicine Residency Carl R. Darnall Army Med Center Fort Hood, Texas Medical Officer, Sheriff Bobby Grubbs Brown County, Texas 325 784 6697 (h) 642 5073 (c)

  4. “Last 30-year period warmest of last 800 years”

    Of course — in comparison to LIA *****************************************

  5. The problem is that you cannot meaningfully compare high resolution instrument readings with even low resolution instrument readings. With the “proxies” having an even lower resolution compared with any instrument records.
    That’s be fore even considering the accuracy of any of the readings including if the proxies you have chosen only show temperature.
    30 years is also about half of the PDO cycle too.

  6. The world would be a much better place if we returned to the climate of 700 years ago. Great Famine, Black Plague, beginning of the LIA. Yep, we need to return to the glory years of civilization.

  7. “Officials from the IPCC stress that the leaked draft is not its final product.” The final product of the IPCC will likely be as dark, malleable, and as malodorous as the final product of my cat.

  8. tadchem,

    The next sentence is more telling for me, “A government review is ongoing, so some of the conclusions may be altered.” Not a scientific review, but a political one.

  9. “last 800 years”: cherry picking in its purest form. If you cherry pick 2000 years you get different results.

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