Roy Spencer has taken Craig Loehle's 2000 year temperature reconstruction to 1995 and added the HadCRUT3 to 2007. Obviously, the proxy temperature reconstructions during the Medieval Warm Period would have larger error bars than the current (instrumental) temperatures, so one shouldn't put too much emphasis on small differences between the current peak and the MWP peaks.
Roy Spencer also looked at what the HadCRUT3 trace would look like if temperatures now remained constant for another 15 years (until 2022)...in that case, the temperature trace almost reaches the +0.6 deg C line (just barely
exceeding the warmest MWP peak).
We can clearly see that the coldest part of the Little Ice Age was unprecedented in the past 2000 years, and the subsequent recovery to the Modern Warm Period.
....of climate change around the early 1300s...
Ender, to beg the question is to assume the point in dispute - to smuggle into the premise, the conclusion about to be deduced.
The anecdotal and archaeological evidence from many and varied sources of the MWP in Europe around the early 1300s is pretty compelling.
Archaeological evidence from Meso-America and South America certainly does not indicate that there were any losers there (being near or at the Equator anyway) and the Southern Hemisphere was sparsely populated anyway. It is interesting to note that one of the earliest settlements of New Zealand was in the area of modern Dunedin between 850 - 1100 AD.
Are you denying the existence of the MWP or do you simply find it an 'inconvenient truth' that must be "got rid of"?
You are convinced that most if not all of the recent warming is mostly or solely due to the additional greenhouse gases injected into the atmosphere by mankind in the last, say, 50 years thereby upsetting the natural balance.
You appear to reject any significant contributing factors like the sun.
You also appear to reject any beneficial effects that might flow from more atmospheric CO₂ or a warmer climate.
That's all fine but if you are a trained and practicing scientist you must know that all alternative explanations for the observed events must be explored equally and I don't believe you are even prepared to that.
I was not suggesting that there is a false assumption behind AGW.
I was suggesting that the computer models that purport to predict future temperatures have false assumptions written into them.
It is ridiculous to suggest that because the AGW hypothesis cannot be disproved, therefore it must be true - you must take me for a fool.
Time will tell.
INCOMING !!
http://www.realclimate.org/index.php?p=502
has to hurt !
Craig: I’m still fascinated by your reckoning on this process. How much raw data was used up front in the original proxies?
“I guess that Work Choices was that which gave Labor such a large majority – deep down I sorta knew that the day had come. There were too many negatives around, drought, interest rises, crap hospitals, schools, transport and and and. People being what they now are don’t blame themselves, i.e. if you’re in supposedly in the driver’s seat – you get the blame”
Arnost; something missing above and its called “arrogance”.
JH n co had it coming for a while and it’s called a quick “punch in the mouth”. Apart from the campaign of dirty tricks right up to election day there was all the put downs. Aussies won’t stand for someone taking advantage of a situation especially when it comes from a trumped up class structure. A fair go means “a fair go”
Note; I never said Ta Ta to Arnost after reckoning he’d be back soon enough.
Have a go mate its still a free country.
Arnost - "No they are not - A doubling of CO2 will result in a temp increase on the order of 1°C. So at most the observed increase in C02/CH4 could have at most caused 30% of the observed temperature increase so far."
You are confusing climate sensitivity with the actual heating effect of the radiative balance of the Earth being out by +4W/m^2. In response to this imbalance the Earth's ocean/atmosphere will heat up to restore the radiative balance.
Climate sensitivity is an estimate of what would happen if CO2 was doubled. It ranges from a low of 1° to a more generally accepted figure of 1.5° to 4.5°.
In a radiative model the resultant forcing from summing the known forcings is of sufficient magnitude to account for recent warming - this has nothing do with estimates of climate sensitivity.
Arnost - "The other fatal flaw in your logic is that you make an assumption that there is NOTHING ELSE that can also explain the temperature increase in the last century."
I or anyone else did no such thing. ALL forcings are considered. The solar forcing is there for all to see:
http://www.nap.edu/openbook.php?record_id=11175&page=29
and is about 0.3W/m^2.
I make no such assumption as the forcings have been measured pretty accurately. Do you have data or a reference that shows that the forcing are different?
Arnost -
"It would be interesting to see what would happen if this type modeling was also done using the Loehle reconstruction. " errr - nope the modelled answer would still be the same.
Luke,
"Many would disagree" ONLY because they factor in a significant feedback from H20. Ender did not include reliance on this feedback in his logical thesis - so, as it is, it is falsified and needs to be improved / revised.