Past decade warmest in 1,300 years

[Barrett808]

Past decade warmest in 1,300 years
Tom Spears, Canwest News Service
Published: Tuesday, September 02, 2008

Another week, another study showing Earth is warming up - with a twist.

This time researchers say there's firmer confirmation for their theory that the past decade has been warmer than anything in the previous 1,300 years. In fact, that might stretch to 1,700 years, they say - depending on whether they rely on the controversial evidence of tree rings showing fast and slow growth as the climate varied centuries ago.

The new study, headed by chief researcher Michael Mann of Penn State University, shows what many previous models have shown. Today's climate is about 0.9 degrees warmer than the long-term average for a period of more than 1,000 years.

The model shows a medieval warm period, not quite as warm as today, from about 700 AD until possibly as late as 1500, followed by a cooler "Little Ice Age" for several centuries. The temperature has warmed up since 1900, with a dip around 1940 to 1970.

But Mann says the real discovery lies in ironing out uncertainties that have plagued climate research.

"It's easy to produce a reconstruction" of past climates, he said in an interview. "But to actually show that it's likely to be meaningful requires a lot more work."

(more)

http://www.canada.com/topics/technology/story.html?id=f8d46935-258d-4234-bc7d-945940d92503

Climate 'hockey stick' is revived
By Richard Black
Environment correspondent, BBC News website

Michael Mann's team analysed data for the last 2,000 years, and concluded that Northern Hemisphere temperatures now are "anomalously warm".

Different analytical methods give the same result, they report in Proceedings of the National Academy of Sciences.

The 1998 hockey stick was a totem of debates over man-made global warming.

The graph - indicating that Northern Hemisphere temperatures had been roughly constant for 1,000 years (the "shaft" of the stick) before turning abruptly upwards in the industrial age - featured prominently in the Intergovernmental Panel on Climate Change's (IPCC) 2001 assessment.

...

"We used two different methods that are quite complementary in the assumptions they make about data, so that provides a test of the sensitivity of data to the methods used," he told BBC News.

"We also made use of a far wider network of proxy data than previously available.

"Ten years ago, the availability of data became quite sparse by the time you got back to 1,000 AD, and what we had then was weighted towards tree-ring data; but now you can go back 1,300 years without using tree-ring data at all and still get a verifiable conclusion."

Both analytical methods produced graphs similar to the original hockey stick, though starting further back in time. The "shaft" now extends back to about 700 AD.

The same basic pattern emerged when tree-ring data - whose reliability has been questioned - was excluded from the analysis.

"I think that having this extra data and using more methods to analyse it makes the conclusions more robust," commented Gabi Hegerl from the University of Edinburgh, UK, who was not involved in the research.

(more)

http://news.bbc.co.uk/2/hi/science/nature/7592575.stm

[Greyskye]

1. So? That's less than 1/6 the age of the Earth

That's like saying that Sunday was the hottest day in the past week.

:sarcasm: :sarcasm: :sarcasm: :sarcasm: :sarcasm: :sarcasm: :sarcasm: :sarcasm: :sarcasm:

[Barrett808]

3. Heh.

I had to do a double-take to get the joke!

[The Croquist]

2. Complete crap.

Nobody knows accurately what the temperature of the planet was 40 years ago let alone 1,300 or 1,700 years ago.

This is the moderate equivalent of the "boy crying wolf". The saddest thing is the scientists know better.

Michael Mann has no credibility. When he created his "Hockey Stick" model he relied heavily on tree rings. Now that his tree ring data was proven unreliable he comes up with other alternatives. When these alternatives are discredited he will come up with more.

[Greyskye]

4. I see.

So you don't believe that man is contributing to global warming? :shrug:

[The Croquist]

6. I do believe that man is contributing to global warming.

I just think it's closer to the effect of a 6 year old taking a piss in a pool compared to a sunny day.

[Greyskye]

7. And you really believe...

that "Nobody knows accurately what the temperature of the planet was 40 years ago let alone 1,300 or 1,700 years ago."

No one knows what the temperature was 40 years ago? You really don't see the absurdity of that?

Whatever. :eyes:

[The Croquist]

10. Yes I really believe that..

Without satellite data there is no accurate temperate data for the planet. The surface record of the planet is not accurate today let alone 40 years ago.

You can call it absurd all you want but why don't you tell me how they measured the temperature at:
The North Pole 40 years ago.
In Antarctica 40 years ago.
The Atlantic, Indian and Pacific oceans 40 years ago.

The United States has over 1,000 surface stations but more then half of them fail to meet NOAA's guidelines and are considered to have an error factor of +/- 2 degrees C. When you are arguing about tenths of a degree I don't see how an error factor of +/- 2 degrees can be considered acceptable. That is the surface stations in the United States today.

Nobody knows what they looked like 40 years ago or what most of the worlds stations look like today let alone 40 years ago. That is the problem.

Here is a picture of the surface station run by the Department of Atmospheric Sciences at the University of Arizona, Tucson. They put it in a parking lot on top of asphalt. This station has been in operation since 1867. I doubt it was on asphalt back then. This is what is refereed to as a class 5 site (error factor of +/- 5 degrees). You would think that the Department of Atmospheric Sciences at the University of Arizona would have known better.

http://gallery.surfacestations.org/main.php?g2_itemId=12970&g2_imageViewsIndex=3

PS: Yes it is a skeptic site.

[Barrett808]

13. The old Urban Heat Island appeal, eh?

Forgive me for referring you to actual climate scientists again:

No man is an (Urban Heat) Island
2 July 2007
http://www.realclimate.org/index.php/archives/2007/07/no-man-is-an-urban-heat-island/langswitch_lang/zh

Observant readers will have noticed a renewed assault upon the meteorological station data that underpin some conclusions about recent warming trends. Curiously enough, it comes just as the IPCC AR4 report declared that the recent warming trends are "unequivocal", and when even Richard Lindzen has accepted that globe has in fact warmed over the last century.

...

There is nothing wrong with increasing the meta-data for observing stations (unless it leads to harassment of volunteers). However, in the new found enthusiasm for digital photography, many of the participants in this effort seem to have leaped to some very dubious conclusions that appear to be rooted in fundamental misunderstandings of the state of the science. Let's examine some of those apparent assumptions:

Mistaken Assumption No. 1: Mainstream science doesn't believe there are urban heat islands….
Mistaken Assumption No. 2: … and thinks that all station data are perfect.
Mistaken Assumption No. 3: CRU and GISS have something to do with the collection of data by the National Weather Services (NWSs)
Mistaken Assumption No. 4: Global mean trends are simple averages of all weather stations
Mistaken Assumption No. 5: Finding problems with individual station data somehow affects climate model projections.
Mistaken Assumption No. 6: If only enough problems can be found, global warming will go away

[The Croquist]

14. Mistakes

1. Mainstream Science certainly recognizes urban heat islands (UHI) and takes efforts to adjust for them. The question is "how much to adjust"? Keep in mind that we are talking tenths of a degree. How much do you adjust per year?
By the way. The Tucson surface station has not only a UHI issue but micro-site heating problem as well. Moving the thing out of the parking lot and onto the grass would have helped.

2. Mainstream science may not think that all stations are perfect but since they have taken no effort to quantify the quality of the stations they don't know how good the stations are / were. Without accurate data on the quality of the stations today AND the quality of the stations 10, 25, 50, 75 and 100 years ago how do you know what they were like?

3. So what are the CRU and GISS stations used for?

4. The data is adjusted by an ever changing analog that looks at other nearby stations to look for differences that may show issues and rates the quality of the data. That is why when an error in data dating back to 2000 was found and "corrected" the temperatures from the 1990s was also changed. It's an interesting program that says "yesterdays temperature is subject to change depending on tomorrows temperature".

5. Finding problems in hundreds of stations should change models if they used actual data for verification instead of just theory. How can a model be independent of the input unless there is no input? Garbage in, garbage out.

6. This starts with the assumption that global warming is caused by man. Without that assumption the models are garbage. Temperatures have risen in the last 30 years. The question is "is it more then just normal fluctuation, if so how much is man made"? If you want to know how much temperatures have risen in the last 100 years you need to accurately know what the temperature was 100 years ago. You don't know that.

The surface stations were not designed for measuring long term climate change. They were designed to provide a record of local weather. If they had been expected to record temperatures within a tenth of a degree they would have been provided with thermometers that were accurate to within a tenth of a degree. The stevenson screens would have been properly maintained including painting, the sites audited, accurate records kept of where they were, the quality of the site and overlapping of site moves so that site temperature changes could be identified and recorded. None of these things happened until recently and not uniformly.

Try standing a hundred yards away from a friend and yelling at him in the middle of a hurricane and see if he knows what you are saying. If he can't try adjusting the sound of the hurricane to pick up what you said. You might be able to do it IF you knew what you said but good luck if you don't know what the correct answer was ahead of time.

Now why don't you answer this question:
When did man made global warming start?

[Barrett808]

20. Please click through for answers to your questions:

http://www.realclimate.org/index.php/archives/2007/07/no-man-is-an-urban-heat-island/langswitch_lang/zh

Before I answer your question, I'm still waiting for you to answer mine:

Now consider the reflectivity of Venus's cloud deck more than makes up for its proximity to the sun
http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=102&topic_id=3447905&mesg_id=3452895

That's your homework. When you can answer it correctly, then we can have a more fruitful discussion.

[The Croquist]

24. Actually I did answer your questions just not the way you wanted me to.

I never saw the one regarding Venus. I posted a response over there:
http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=102x3447905#3474173

By the way you won that argument.

I look forward to a fruitful discussion.

[Barrett808]

25. I'm sure we'll have many more opportunities for discussion

In the meantime, be well.

:toast:

[Viking12]

21. yeah cuz a few photos are a great substitute for statistical analysis

[The Croquist]

23. Actually it is a few thousand photos and a few hundred reports

covering about 50% of the USHCN surface station network. This was done my many unpaid, untrained volunteers with no government money. They used their own time, gas and equipment (camera, GPS and tape measures). The initial government response to this project was to lock people out of the database to make it as difficult as possible to audit the sites.

Perhaps you can point to a better and more detailed analysis of the surface station network that has been done recently or ever. I am certainly not aware of one.

As of the last update:

4% are considered Class 1 (the best)
9% are considered Class 2
18% are considered Class 3 (accurate to 1 degree)
56% are considered Class 4 (accurate to 2 degrees)
13% are considered Class 5 (accurate to 5 degrees)

Why don't you take a look at the site closest to your house or better yet review one nearby. They could use help (I haven't done it).
You can browse here. http://gallery.surfacestations.org/main.php?g2_itemId=20

The nearest station to me is Covington GA. The person who did it, Don Kostuch, did a good job. He has 2 aerial views (from google earth), a map, 4 close up photos, a chart showing the temperature records dating back to about 1880 (with 2 large gaps prior to about 1930) and submitted a written report.

The station is 15 feet from a maintenance building on a golf course with an air conditioner 20 feet away. That makes it a class 4.
http://gallery.surfacestations.org/main.php?g2_itemId=23713&g2_imageViewsIndex=4

Not all reports are as well done but most are helpful.

Rather then accept that there is a problem with the quality of the data the reaction is to attack the integrity of the people doing the work. They should be thanked not ridiculed.

[Viking12]

22. You know the satellites don't measure the north pole, right?

[The Croquist]

26. Yes I do.

I'm winging this but I think RSS claims accuracy to about 80 degrees and UAH (Alabamastan) doesn't include quite so far. They still cover allot more of the planet then the surface data system with a great deal more uniformity of the methodology.

[Barrett808]

8. If you feel so strongly about it, why don't you tell Mike Mann over at RealClimate?

There's an open thread on this topic:

Progess in reconstructing climate in recent millennia
http://www.realclimate.org/index.php/archives/2008/09/progress-in-millennial-reconstructions/langswitch_lang/zh

[The Croquist]

11. I am not qualified to debate Mann

However Steve McIntyre over at Climate Audit is.

http://www.climateaudit.org/

You may want to ask Mann why he was so against sharing his data and code.

[Barrett808]

12. Mann's data and code are posted here:

Supplemental Information for PNAS Article "Proxy-Based Reconstructions of Hemispheric and Global Surface Temperature Variations over the Past Two Millennia"
http://www.meteo.psu.edu/~mann/supplements/MultiproxyMeans07

[The Croquist]

15. Some Thoughts on Disclosure and Due Diligence in Climate Science

by Steve McIntyre on February 14th, 2005

http://www.climateaudit.org/index.php?p=66

In the case of the Mann et al <1998,1999> study, used for the IPCC's "hockey stick"? graph, Mann was initially unable to remember where the data was located, then provided inaccurate data, then provided a new version of the data which was inconsistent with previously published material, etc.

In addition to the lack of due diligence packages, authors typically refuse to make their source code and data available for verification, even with a specific request. Even after inaccuracies in a major study had been proven, when we sought source code, the original journal (Nature) and the original funding agency (the U.S. National Science Foundation) refused to intervene. In the opinion of the latter, the code is Mann's personal commercial property. Mann recently told the Wall Street Journal that "Giving them the algorithm would be giving in to the intimidation tactics that these people employ"?. My first request for source code was a very simple request and could in now way be construed as "intimidation"?.

[Barrett808]

17. The code and data are publicly posted, what else do you want? n/t

[GliderGuider]

16. In that case, what qualifies you to call his conclusions "complete crap"?

If Mann is better informed and more scientifically sophisticated than you (which is what "qualified" comes down to), why do you feel justified in making categorical pronouncements on his conclusions?

[The Croquist]

18. Because I can read

I have read from those that are qualified to call his conclusions "complete crap"

[Barrett808]

19. Well, he can read Climate Audit.

But he refuses to read an actual textbook on climate science.

[bhikkhu]

5. So we are now warmer than the medieval warm period...

I had been curious about that. I read a book about it awhile back where that period was portrayed in some ways as an anomalously peaceful and stable era in human history, at least in Europe. While having balmy temperatures was probably nice, I think any number of median temperatures cold be adapted to and flourished in, as long as they remained stable. I think now it is not so much the "warming" as the volatility that is the big issue.

edit:sp

[Barrett808]

9. Here's the new "hockey stick" graph:

Figure: Spaghetti plot of the new reconstructions over a) 1800 and b) 1000 years along with selected older ones for comparison.
http://www.realclimate.org/index.php/archives/2008/09/progress-in-millennial-reconstructions/langswitch_lang/zh