The summer water temperatures, reconstructed from the makeup of tiny organisms buried in sediments in the Fram strait, have risen from an average 5.2 degrees Celsius (41.36F) from 1890-2007 and about 3.4C (38.12F) in the previous 1,900 years.
The findings were a new sign that human activities were stoking modern warming since temperatures are above past warm periods linked to swings in the sun's output that enabled, for instance, the Vikings to farm in Greenland in Medieval times.
ER, UM... THEY WERE FARMING IN GREENLAND BACK THEN DURING THE MWP - AND YOU CANNOT NOW - (DESPITE "MAN-MADE CO2 AND SUV'S!); ERGO: IT IS NOT WARMER NOW THAN THEN.
IDJITS.AND ANOTHER THING: WARM WATER MIGHT BE THE RESULT OF UNDERSEA VOLCANOES.
5 comments:
Why does the MWP matter if there is no such thing as global temperature?
MWP WAS KNOWN TO BE REGIONAL;
THERE WAS NO ONE TAKING LOCAL TEMPS IN MOST OF THE WORLD BACK THEN.
BUT WE KNOW THAT EUROPE AND GREENLAND WERE BOTH WARM FROM DIRECT OBSERVATION OF THE PEOPLE THEN.
AND IT PROVES THAT THE RECENT WARM ERA IS NOT UNIQUE OR EVEN AS WARM AS EARLIER ERAS.
OKAY!?!??!!?
So, "direct observations" are just a bunch of people writing down how warm it felt? Is qualitative data OK in this case?
How can you compare a regional phenomenon in the past based on qualitative data with a global phenomenon in the present based on quantitative data?
"THE RECENT WARM ERA IS NOT UNIQUE OR EVEN AS WARM AS EARLIER ERAS."
See this chart, which clearly shows the MWP was not as warm as current times. Note that the chart only goes up to 2000, so misses out on the last decade of warming.
Crowley and Lowery point out that you can't just pick and choose which individual records you use to determine how warm the MWP was. You've got to take all the evidence and form a composite dataset:
"A frequent conclusion based on study of individual records from the so-called Medieval Warm Period (1000-1300 A.D.) is that the present warmth of the 20 th century is not unusual and therefore cannot be taken as an indication of forced climate change from greenhouse gas emissions. This conclusion is not supported by published composites of Northern Hemisphere climate change, but the conclusions of such syntheses are often either ignored or challenged. In this paper, we revisit the controversy by incorporating additional time series not used in earlier hemispheric compilations. Another difference is that the present reconstruction uses records that are only 900–1000 years long, thereby, avoiding the potential problem of uncertainties introduced by using different numbers of records at different times. Despite clear evidence for Medieval warmth greater than present in some individual records, the new hemispheric composite supports the principal conclusion of earlier hemispheric reconstructions and, furthermore, indicates that maximum Medieval warmth was restricted to two-three 20–30 year intervals, with composite values during these times being only comparable to the mid-20 th century warm time interval. Failure to substantiate hemispheric warmth greater than the present consistently occurs in composites because there are significant offsets in timing of warmth in different regions; ignoring these offsets can lead to serious errors concerning inferences about the magnitude of Medieval warmth and its relevance to interpretation of late 20 th century warming."
This is a much-cited paper: 264 citations, which means its findings have taken hold among climate scientists.
Post a Comment