A little while back the climate change community was all abuzz with news that a new hockey stick graph had been reported in the peer-reviewed literature. Believers in the consensus were cock-a-hoop and it was reported in all the usual places. Within OLO a thread entitled "Too Fast" was started to celebrate the breakthrough paper.

The paper was called Marcott et al 2013 and purported to show the temperatures over the past 11300yrs. It showed a steady rise for 5000yrs or so, then a steady decline for 5000yrs up to around 1900 when temperatures rapidly rose, wiping out all the decline in the previous 5000yrs.

Unfortunately for the authors (but fortunately for those who treasure the truth) Steve McIntyre looked into the data behind the graph and the results have been sensational.

Long story short, the authors, who originally were crowing that “What we found is that temperatures increased in the last 100 years as much as they had cooled in the last 6,000 or 7,000,” are now back-tracking as fast as they can and are reporting “the 20th century portion of our paleotemperature stack is not statistically robust, cannot be considered representative of global temperature changes ..“. ie you can't rely on anything their data says about the 20th century.

So we don't have a hockey stick but an upturned U-shaped graph where the all the bumps are ironed out by averaging with a resolution of ~300yrs. The authors are also conceding that their work can't rule out the likelihood that there have been many other periods like the 20th century where temperatures rose by 0.5 degrees or so. Finally to make matters even worse for the authors there is more investigation into the processes behind the paper with some not ruling out professional misconduct on the part of the authors.

The other interesting aspect to this is to see how well the 'clarifications' from the authors are reported given that the original, now discredited graph was widely covered by the press.

MHaze,

You’re a bit slow off the mark. Isn’t this the same report Poirot was crowing about here: http://forum.onlineopinion.com.au/thread.asp?discussion=5668#157478

It seems she swallowed it hook line and sinker--ROFL

(now watch, she is going to come in with some yada about how bad Lord Monkton is, to throw you off the trail)

mhaze,

Ho hum.....

http://tamino.wordpress.com/2013/03/22/the-tick/

http://tamino.wordpress.com/2013/04/02/for-the-record/

Have you guys an explanation for the rate of warming in modern times?

Or do you subscribe to the line that nasty Marcott smeared out all the warmish periods in the Holocene?

I suppose it's nice to have a hobby, but hunting down and thrashing hockey sticks is so passe these days.

"We already know what happened in the 20th century."

Okay boys, obviously the game's up....

Apparently, according to the "NO CARBON TAX Climate Skeptics Party", we're heading for a mini ice age...and it's already upon us!

http://theclimatescepticsparty.blogspot.com.au/2013/04/mini-ice-age-has-started-prof-warns.html

Fascinating......

Poirot. "Have you guys an explanation for the rate of warming in modern times?"

That's too big a question to answer here. I'll simply observe that we are comparing a detailed instrumental record for maybe a couple of hundred years containing multiple adjustments to a proxy record of the last 10,000 years. Although I can't comment as an expertly informed observer, I am suspicious proxies are unable to match an instrumental record for accuracy or reliability. If they did, we could scrap thermometers tomorrow and rely on reading tree rings or teabags or something for contemporary scientific research.

Regardless, Tamino as I observed earlier is twisting and turning like mad to save the day. But simply put, the confirming uptick is not there. You may wish to read Marcott's own response here:
http://www.realclimate.org/index.php/archives/2013/03/response-by-marcott-et-al/

Here's a relevant quote:

"Q: What do paleotemperature reconstructions show about the temperature of the last 100 years?

A: Our global paleotemperature reconstruction includes a so-called “uptick” in temperatures during the 20th-century. However, in the paper we make the point that this particular feature is of shorter duration than the inherent smoothing in our statistical averaging procedure, and that it is based on only a few available paleo-reconstructions of the type we used. Thus, the 20th century portion of our paleotemperature stack is not statistically robust, cannot be considered representative of global temperature changes, and therefore is not the basis of any of our conclusions. Our primary conclusions are based on a comparison of the longer term paleotemperature changes from our reconstruction with the well-documented temperature changes that have occurred over the last century, as documented by the instrumental record. Although not part of our study, high-resolution paleoclimate data from the past ~130 years have been compiled from various geological archives, and confirm the general features of warming trend over this time interval (Anderson, D.M. et al., 2013, Geophysical Research Letters, v. 40, p. 189-193; http://www.agu.org/journals/pip/gl/2012GL054271-pip.pdf).