To start with no one is entirely sure how warm the Medieval Warm period was, and definitely what the temperatures of Greenland were. It does seem clear though that Greenland was warmer and a number of climate reconstructions do have varying amount of warming, some little other more from that time period. The regional nature of the climate change of this period and type of proxy likely contribute to those model differences. See my post below for agriculture on Greenland and links for "Medieval Warm period"

As for the Icesheets, a major study was conducted by Ola M. Johannessen, Kirill Khvorostovsky, Martin W. Miles, Leonid P. Bobylev 2, 2005, titled "Recent Ice-Sheet Growth in the Interior of Greenland". To view the abstract.

http://www.sciencemag.org/cgi/content/abstract/1115356v1

Also a good summary from where my quotes are taken from

http://www.sciencedaily.com/releases/2005/11/051107080830.htm

In any regard, ill sum up the import part of this research, by taking a variety of their statements

"The result is a mixed picture, with a net increase of 6.4 centimetres per year in the interior area above 1500 metres elevation. Below that altitude, the elevation-change rate is minus 2.0 cm per year, broadly matching reported thinning in the ice-sheet margins. The trend below 1500 metres however does not include the steeply-sloping marginal areas where current altimeter data are unusable."

"The spatially averaged increase is 5.4 cm per year over the study area, when corrected for post-Ice Age uplift of the bedrock beneath the ice sheet. These results are remarkable because they are in contrast to previous scientific findings of balance in Greenland's high-elevation ice."

This means the icesheet is growing in +1500m elevation in the central portions while the edges or margins are shrinking. Furthermore, the reasons given for these changes include

"interior growth of the Greenland Ice Sheet to increased snowfall linked to variability in regional atmospheric circulation known as the North Atlantic Oscillation (NAO). First discovered in the 1920s, the NAO acts in a similar way to the El Niño phenomenon in the Pacific, contributing to climate fluctuations across the North Atlantic and Europe."

"Modelling studies of the Greenland Ice Sheet mass balance under greenhouse global warming have shown that temperature increases up to about 3ºC lead to positive mass balance changes at high elevations – due to snow accumulation – and negative at low elevations – due to snow melt exceeding accumulation."

In orderwords the ice isnt getting thicker because the climate in greenland is cooling but the warming is affecting weather patterns such that greater amounts of snow are accumulating in the higher elevations, while in the lower elevations are melting due to the increased warming.

To start with no one is entirely sure how warm the Medieval Warm period was, and definitely what the temperatures of Greenland were. It does seem clear though that Greenland was warmer and a number of climate reconstructions do have varying amount of warming, some little other more from that time period. The regional nature of the climate change of this period and type of proxy likely contribute to those model differences. See my post below for agriculture on Greenland and links for "Medieval Warm period"

As for the Icesheets, a major study was conducted by Ola M. Johannessen, Kirill Khvorostovsky, Martin W. Miles, Leonid P. Bobylev 2, 2005, titled "Recent Ice-Sheet Growth in the Interior of Greenland". To view the abstract.

http://www.sciencemag.org/cgi/content/abstract/1115356v1

Also a good summary from where my quotes are taken from

http://www.sciencedaily.com/releases/2005/11/051107080830.htm

In any regard, ill sum up the import part of this research, by taking a variety of their statements

"The result is a mixed picture, with a net increase of 6.4 centimetres per year in the interior area above 1500 metres elevation. Below that altitude, the elevation-change rate is minus 2.0 cm per year, broadly matching reported thinning in the ice-sheet margins. The trend below 1500 metres however does not include the steeply-sloping marginal areas where current altimeter data are unusable."

"The spatially averaged increase is 5.4 cm per year over the study area, when corrected for post-Ice Age uplift of the bedrock beneath the ice sheet. These results are remarkable because they are in contrast to previous scientific findings of balance in Greenland's high-elevation ice."

This means the icesheet is growing in +1500m elevation in the central portions while the edges or margins are shrinking. Furthermore, the reasons given for these changes include

"interior growth of the Greenland Ice Sheet to increased snowfall linked to variability in regional atmospheric circulation known as the North Atlantic Oscillation (NAO). First discovered in the 1920s, the NAO acts in a similar way to the El Niño phenomenon in the Pacific, contributing to climate fluctuations across the North Atlantic and Europe."

"Modelling studies of the Greenland Ice Sheet mass balance under greenhouse global warming have shown that temperature increases up to about 3ºC lead to positive mass balance changes at high elevations – due to snow accumulation – and negative at low elevations – due to snow melt exceeding accumulation."

In orderwords the ice isnt getting thicker because the climate in greenland is cooling but the warming is affecting weather patterns such that greater amounts of snow are accumulating in the higher elevations, while in the lower elevations are melting due to the increased warming.

John, have you ever been on a farm or are you a city slicker? I always get a laugh when people use this as proof that the MWP was warmer than present. You like to put out this image of the Vikings being "farmers" to support your misinformed view of reality. Ahhh, visons of golden fields of wheat, barley (did they have breweries too, John) then nasty old climate changed and it got so cold that the crops died. Hogwash.

They were no more farmers that the Inuit and others who have lived there for thousands of years. Yes, they had a few cows and sheep probably feeding on seaweed and coarse grasses. However, the one factor that was missing and cannot be created over a short time span, such as the MWP, is soil. As any farmer knows, soil is the key to farming not temperature. That is what is lacking in Greenland since if the ice retreated for a few centuries there was not nearly enough time to make soil which takes thousands of years to form.

The "fields" were enclosed so that the animals didn't wander. Why would they put a stone wall round a field of wheat?

As I mentioned it was lack of soil which prevented serious farming not temperature.

And what about all the wine they were supposed to be growing and drinking? Isn't that why the called Labrador Vinland? All stories and lots of PR just like the AGW deniers.

I recognize BS when I step in it. Funny that you people will not accept data and conclusions from the world's best scientists but believe everything written in 1000 year old "fairy tales".

There are many reasons why the Norse decided to leave Greenland, lower temperatures is only one of a number of reasons. It is an exaggeration to call what they were doing "farming" as we presently know it and what was considered farming in Europe at that time. It was a meager form of subsistence agriculture.

One of the reasons put forward was that they overgrazed the available land. Evidence for this was the badly eroded teeth of the sheep unearthed by archaeologists (from soil particles and found when forage was very poor and about to give out). This site was dated to just before the Norse left.

However, another site, about 200 years earlier was found when forage should have been much better since it was supposed to be warmer. However, the teeth were almost identical to those found 200 years later showing that forage was at a very low level for most of the time the Norse were on Greenland.

Now if they were farming as you suggest, then why the bad forage? Surely they must have been growing luxuriant hay crops for their sheep.

I found this one: http://www.ncdc.noaa.gov/paleo/globalwarming/medieval.html

Do you have a different one that actually matches what you're claiming, or are you just making stuff up?

Also, what part of the definition of the word "Global" in the phrase "Global Warming" don't you understand? Surely anecdotal evidence of the temperature of Greenland in the past is merely an indication of a different distribution of the same total atmospheric energy, and nothing more?

About farming in greenland thats entirely untrue. People have been surviving for years growing a variety of forage crops, and live stock. Not generally intensive by any means, its likely not that different from more historic farming practices in terms of intensity. Cia.gov site lists agricultural products as forage crops, garden and greenhouse vegetables; sheep, reindeer; fish. Granted while fish are likely all oceanic they could be farmed that is unknown to me. However sheep and reindeer are likely herded and forage crops grown to feed them and pasture land would be used.

While it seems anidotical exactly how warm greenland was, no temp records were kept by those industrious scandanavians, good evidence exists for a warmer greenland at that time none the less. However, current research suggests that the warming of the period was distinctively regional and most people tend to be very Euro-centric about this.

http://www.grida.no/climate/ipcc_tar/wg1/070.htm

Furthermore I'd assume the Norse farmers of historic record were not exactly growing intensive crops corn or canola, but likely the same types of things that have been "farmed" on greenland during the more modern age ie post 1900.

After all, he's a greedy scientist shamelessly chasing grant money, isn't he? Dr. Solanki's recommendation: more research, and lots of it.

Still, I wonder why, with all those juicy quotes from Dr Solanki, Solomon didn't include this one:
Just how large [the Sun's] role is, must still be investigated, since, according to our latest knowledge on the variations of the solar magnetic field, the significant increase in the Earth’s temperature since 1980 is indeed to be ascribed to the greenhouse effect caused by carbon dioxide.

I guess Solomon's own conlcusion--"Until the research is in, he believes, the story of what drives climate change remains unknown"-- just reads a little better.

Oh well, every almost perfect correlation has to end some time.

Zog, us "warmers" have a "special hatred" for Solomon because he constantly includes misleading information as well as misconceptions, falsehoods, etc. in his articles about climate change.

Yet again you show us what a powerhouse of logic and objectivity the denialist camp is. However, don't you think you'd do a little better by following Solomon's lead and fabricating your arguments? Might be even more effective than childish, ad hominem remarks.

I don't want Larry to shut up. I just think he should move his offering to the fiction section, where it belongs.

And as for his politics, why should I care if he's left wing (even if he was)? Why should I care if he's an environmentalist (setting aside all evidence to the contrary)?

My concern is that he misrepresents scientists as deniers of anthropogenic global warming - and then refuses to acknowledge that misrepresentation, even when one of those scientists demands a retraction.

The former could merely be shoddy journalism. The latter is evidence of an intention to deceive. 

Nobody really knows what the average global temperature is now or was in the MWP.

Someone linked to the "hockey stick" chart of the last 1,000 years which has since been discarded (it was made-up statistics and I don't know why it is still being used on websites.)

The two organizations which measure global temperature - the Hadley Centre and NASA's GISS - have been systematically adjusting all the historical temperature records down and the most recent temperatures up.

Nobody knows if temperatures were higher in the 1930s than now. Before the Hadley Centre and GISS adjusted the 1930s temperatures downward, 1940 was thought of as the highest yearly temperature recorded.

Anonymous, that is completely full of crap and is slanderous/libelous against the Hadley Centre and the GISS as well as MBH.

You're a liar or worse, a bulls****er who knows your're wrong but are trying to screw with the minds of the public to suit your flawed and oblivious opinion. Stop your crap now!

Here is GISS - James Hansen's own paper showing how he adjusted US temperatures by a total of 0.35C (1940 down by 0.1C and 2000 up by 0.25C).

This is only the first of many such adjustments made by GISS and Jones from the Hadley Centre (without publishing a paper on what they did - like Hansen did at least with the 2001 adjustments.)

Not Libel. FACT. (that is convienently not publicized because it advances the global warming cause.)

I will revise my post.

Anonymous, you've told the worst lie of all. A partial truth or the truth told in a certain way.

First of all, the "hockey stick" is not broken one bit, but affirmed by Wahl and Ammann (2006). It also figures prominently in the scientific basis the IPCC has synthesised.

Secondly, the GISS and Hadley Centre's adjustments are very minor and only take into account small disparities and sensitivities in the data collected. Otherwise, there would be irregularities in the synopsis of a certain situation.

As for this comment:

"Nobody knows if temperatures were higher in the 1930s than now. Before the Hadley Centre and GISS adjusted the 1930s temperatures downward, 1940 was thought of as the highest yearly temperature recorded."

Complete rubbish. It is beyond question that temperatures today are higher than during the 1930s and 1940s. Anyone who says otherwise is a fool. Every single major national scientific association in the G8 as well as every major climate research organisation has agreed that today's temperatures are the warmest they have ever been as far back as at least 400 years.

I apologise for the over-energetic comments before. However, it pisses me off to read such blatant obfuscation and dishonesty without explanation and clarification of one's comments as well as false accusations of academic fraud leveled against such scholars as Dr. Hansen. It seems to be a specialty of the "denier" crowd.

Now that you know they have been playing around with the data, do you really know it is warmer today than 1940? That is all I said - no one really knows.

And the hockey stick was completely replaced in the latest IPCC report AR4.

"And the hockey stick was completely replaced in the latest IPCC report AR4."

That's complete rubbish, as well, as the AR4 hasn't yet been released. Only the SPM has been released with the WG1 report scheduled for release next month. Therefore, you have no idea what the heck is in it yet, unless, that is, you are one of the lead authors which I highly doubt based on your ignorance of the science of climate change.

The working group drafts have been leaked. I imagine you haven't read them yet. I have however.

Hockey Stick replaced with a spaghetti graph of ALL the recent (showing global warming) reconstructions (not the reconstructions which might show other trends.)

Just to add further to my point, the Hadley Centre adjusted the temperature record yet again late in 2006.

Remember when we used to think the temperature rise since 1900 was 0.6C. Well, that is old now. Hadley has changed it 0.8C. [If you can find the paper when they explain what they have done, why they done it, and how they adjusted the data, I would sure like to know.]

By my reckoning, the total adjustments to date are 0.7C. Maybe all the "adjustments" were done for valid reasons. But nobody knows that except for the authors of the adjustments (and they are not talking.)

The 0.8 C comes from this paper (i.e. there is documentation):

Brohan, P., J.J. Kennedy, I. Haris, S.F.B. Tett and P.D. Jones (2006). "Uncertainty estimates in regional and global observed temperature changes: a new dataset from 1850". J. Geophysical Research 111: D12106. DOI:10.1029/2005JD006548.

If you only looked below the graph, you would have seen it. Maybe the ideological smog which blinds you prevented you from reading the information package at the bottom, which reads:

"This image shows the instrumental record of global average temperatures as compiled by the Climatic Research Unit of the University of East Anglia and the Hadley Centre of the UK Meteorological Office. Data set HadCRUT3 was used. HadCRUT3 is a record of surface temperatures collected from land and ocean-based stations. The most recent documentation for this data set is Brohan, P., J.J. Kennedy, I. Haris, S.F.B. Tett and P.D. Jones (2006). "Uncertainty estimates in regional and global observed temperature changes: a new dataset from 1850". J. Geophysical Research 111: D12106. DOI:10.1029/2005JD006548. Following the common practice of the IPCC, the zero on this figure is the mean temperature from 1961-1990."

"Hockey Stick replaced with a spaghetti graph of ALL the recent (showing global warming) reconstructions (not the reconstructions which might show other trends.)"

The spaghetti graph is identical to the latter section of the "hockey stick". It is just a shorter time frame than the 1000-year MBH graph. Again, your ideological blindness prevents you from seeing reality.

As for your comment that the AR4 shows only the recent reconstructions which show global warming and does not show "reconstructions which might show other trends", that is because no reconstructions exist which show other trends.

Also, very typical of the cretins at JunkScience to leak the draft of the AR4. It is typical because those at JunkScience love to circumvent the process and halt (or at least hinder/inhibit) the scientific process so their supporters will be able to go on dumping GHGs into the atmosphere as regulations will be slow coming.