According to peer-reviewed studies, how many periods were most likely warmer than now in the last 4,000 years?

According to Carter, who is widely accepted, there have been three. The Minoan, Roman and Mediaeval.

Rutan discusses this along with other peer reviewed supporting data collection. (page 51)

http://rps3.com/Files/Ochkosh_2010_talks/Oshkosh20...

Yes there were a few warming spells.

The medievil warm period was a little below the warming period we are in today.

Around the time of the Egyptions there was also a warming period. I believe that one was warmer then the one we are currently in.

Along with these warm spells there were cold spells like the little ice age and a period in roman times that lasted a few centeries.

If they were to happen again it would get cold but only around 2 degrees celcius colder than today. Then it will warm up again till the next spell. These arent iceages or greenhouses they occur in 100,00-millions of years. These are just very minor shfts in temperature.

Well you basically answered your own question with regards to the regional characteristics of the study, being Greenland only. This study only deals with Greenland which is affected by such things as solar cycles, certain natural oscillations, and so on more than other areas of the world.

I see you are still linking to CO2 science as if it's actually trustworthy. Furthermore, it is known that the medieval warm period was a global phenomenon that coincided with the Medieval Maximum, the area around Greenland was warmer than currently in that region, and, on average, the medieval warm period was cooler than now and, it is thought, that the MWP average global temperatures were roughly equal to temperatures in the 1950s/1960s. Your reply to Al stating that graph 8 shows that the world is cooling is false as this 'Only deals with Greenland' as you stated in your question. One wonders why, if you already know the answer, you continue posting these types of things.

Edit: Where did I say that they were all funded by Exxon Mobile? Once again you are putting words in my mouth. Looking at these two graphs of the same area, done just 1 year after another, by the same people should give you some skepticism though.

http://www.co2science.org/data/mwp/studies/l1_maka...

http://www.co2science.org/data/mwp/studies/l1_cold...

This site reaches it's own conclusions based on the outcomes of studies that meet their personal opinion. Read more about it here: http://blogs.nature.com/climatefeedback/2008/08/mo...

It was founded and is run by the Idso family. Exxon Mobile has provided a boat load of money to the organization as well as the Idso and their NIPCC. So while the articles and so on may or may not be Exxon funded, I would have to look at each one, the site is and the conclusions reached on the site are out of context regarding the articles. A typical tactic of those who are attempting to manipulate the masses and people who do not check sources, ie. you, seem to lap it up because it meets their predefined beliefs regardless what the sources actually says.

Several things can lead to the same outcome. This particular climate change, while the outcome is similar to past increases that occured over geological time, the cause is different. This situation rests on a sudden release of CO2 from the burning of massive amounts of CO2 in a very short historical period...less than 200 years. Because fossil fuel is taxed, we know how much has been extracted and how much has been burned over most of that 200 year period. Therefore we know how much CO2 has been released. Also know is how many cubic miles of atmosphere surround the Earth and there is a scientific formula to determine how much CO2 is required to increase the heat accumulation in any given parcel of atmosphere.

There's also a feedback reaction that concerns the release of tundra based methane and CO2, plus the reduced acres of trees and other carbon sinks that mostly balance out any increase in CO2 production. It's a long formula, but it's based on scientific laws of atmosphere and heat that are NOT at this point open to any logical counter argument.

We can also directly determine how much CO2 is in the atmosphere, and we know by going back directly in the records for 100 plus years how much there was then, and by indirect means we know how much was present at the beginning of the industrial age..about 1835.

At the beginning of the industrial age CO2 stood at 285ppm. In 1950 it stood at 350ppm. Oddly, for the past 40,000 years it's never been higher than 350ppm. At the end of the last ice age it was 286ppm...10,000 years ago, give or take. Today it's close to 400ppm and rising at at rate of about 15ppm per decade. At 450ppm we reach the the point of the beginning of a rapid and possibly a runaway greenhouse effect. That should be a real concern if you plan on being around come mid century.

So why isn't 'hotter' then it is? Ice. The Earth has a lot of ice. Ice absorbs heat. As ice absorbs heat the ice melts. Put warm beer in your ice chest and the beer cools while the ice melts. Sea water also absorbs heat, but let's stick to the ice. Artic ice is melting at a fantastic historical rate. Ice at the south pole, because it's glacier ice at at higher altitude than sea level artic ice is melting mostly around the edges...slower, but just as steadily.

Conclusion: An atmosphere with more heat trapping gases will trap more heat. The heat in the atmosphere will be absorbed by anything that's colder. When the colder substance such as ice reaches 32.1 degrees F. it will melt. When the ice is gone, as in a freezer chest, the beer will begin to warm up. You won't like warm beer, and you won't like a continually warmer and warmer Earth either.

Humlum, Solheim and Stordahl's paper was thoroughly debunked by real climate scientists:

http://www.realclimate.org/index.php/archives/2011...

If you look at the number of times that paper is cited (and exclude Humlum, Solheim and Stordahl themselves) one realizes the little if any impact their paper has had. In other words, its crap.

More on Humlum and the outrageous claims he has a habit of making:

http://www.skepticalscience.com/humlum-at-it-again...

http://www.skepticalscience.com/crux-of-a-core3.ht...

<<Al, how could you not know that there are numerous studies verifying the Medieval Warming Period and other warm periods?>>

Let's suppose for a moment that there indeed was a global MWP. How on earth would that undermine the current scientific proof regarding AGW?

Edit @ Maxx:

<<Are there any sources MORE biased than the ones you've quoted.... I don't think so.>>

And this coming from someone who regularly links to a Creation website to back-up his claims about climate science. Realclimate is run by actual and active climate scientists. Neither of the authors of the study are. Heck, one even works for a telecomunications company.

<<...CO2science...>>

CO2science is industry funded. Talk about biased... Craid Idso himself is also active in the oilfield supply industry (1).

<< Are you trying to make everyone laugh with you statement about "proof of AGW?" Not only do you have no proof, you don't even have any evidence.>>

There's lots of proof and lots of evidence. The problem is that you are so incredibly biased that you reject all that (just as you reject evolution as a whole).

Now answer this: how does a theoretical global WMP disprove AGW?

Well Maxx you are right this is pertinent to Greenland but has no global application.

Although this may be a peer reviewed paper, Maxx, it is geoscience, not climatology, We have been asking you DA deniers for peer reviewed papers fro a real climatologist which none of you have been able to provide.

Additionally, this is merely an abstract, not the entire paper. Sorry, but once again your question has little or no bearing on the reality of climate change.

Hi my guess would be during the dinosaur days and lavic activity world wide.

Also maybe during biblical times or roman times??

Either way global warming IS man made.

we level the rainforests and the smog from factories, cities and technology, pollution, and nuclear bomb testing destroys the ozone. plus I would not be supprised if off shore drilling does damage to the techtonic plates of the earth casuing a disruption in climate and natural disaters to occur.

That is my hypothesis.

The two I know of are

Medieval warm period

Roman Climate Optimum.

I beleive there is also the holocen optimum but not sure if that is within the past 4,000 years.

please supply references to papers from 'all parts of the globe'. Using a local study as supplied does not investigate the worldwide effect of CO2. I also doubt there has been much changes to the moon's orbit since the 1850's, the subject of today's AGW. We already know solar cycles influence climate, as do el-nino.

BTW.. deniers are still clinging on "the earth is getting cooler", or have they moved on?

@Al: Here are some references for you:

Medieval Warm Period studies in the form of a cool interactive map: http://www.co2science.org/data/timemap/mwpmap.html

Roman Warm Period studies here: http://www.co2science.org/subject/r/subject_r.php

Although more than 4000 years ago, Holocene studies on this page: http://www.co2science.org/subject/h/subject_h.php

me thinks someone is off their rocker

and maxx all i can say is

denier

edit maxx

Jerry - ?

read rockers wisdom about nuclear testing that doesn't happen above ground killing the ozone layer