Posted by
Andrews on Monday, April 27, 2009 2:04:21 PM
It has become commonplace among the proponents of AGW to argue that there was no Medieval Warm Period, as the idea that the Earth was significantly warmer from about 1000 AM until around 1250-1300 AD would disprove the pattern enshrined in the "hockey stick" graph. I have written about this before in my posts "
Very Quick and Simple Logic", "
Some Global Warming Links", "
Fire Up the SUV" and "
More About the Hockey Stick Graph". However, today, while reading about various pre-Columbian South American cultures, I found an interesting statement
in Wikipedia:
The elites power continued to grow along with the surplus of resources
until about AD 950. At this time a dramatic shift in climate occurred.[4]
A significant drop in precipitation occurred in the Titicaca Basin,
with some archaeologists venturing to sugges a great drought. As the
rain became less and less many of the cities furthest away from Lake
Titicaca began to produce fewer crops to give to the elites. As the
surplus of food droppped, the elites power began to fall. Due to the
resiliency of the raised fields, the capital city became the last place
of production, but in the end even the intelligent design of the fields
was no match for the weather. Tiwanaku disappeared around AD 1000
because food production, the empires' source of power and authority,
dried up. The land was not inhabited again for many years.[4]
This is interesting for two reasons. First, because the date of the decline of the Tihaunaco/Tiwanaku culture corresponds so perfectly with the beginning of Medieval Warm Period, but, second, and much more importantly, as it gives evidence of a warm period from the opposite side of the globe.
You see, many AGW proponents have realized that ti is impossible toa rgue against the Medieval Warm Period. Alpine settlements now covered by glaciers, Viking settlements in Greenland now covered with ice and snow, historical records of grapes growing in England, records of cultivation in Scandinavia far north of presently arable lands, and so on have shown them the futility fo arguing against a warm period in Europe.
But, rather than accept that global warming is a natural phenomenon, likely linked to solar cycles, and abandon the insanity fo the "hockey stick", these AGW proponents have argued that the Medieval Warm Period was a regional variation, limited to Europe, which is why it is not reflected in the hockey stick, which draws form worldwide sources. In this way they both argue against any overall global warming in the past, and maintain the validity of the hockey stick.
But if there was a lengthy dry period in the Andes beginning about the same time that Europe experienced a warming period, that makes this argument much less plausible. After all, what other than a global warming trend could both cause a drought in the Andes and a simultaneous warming in Greenland, Iceland and Europe?
Of course, I doubt this will convince any die hard AGW advocates. As I wrote before, many are not precisely honest in their arguments. Many of the rank and file may be sincere, may even be motivated by a belief they are working for the benefit of man, but many fo the theorists of the environmental movement are not that honest. A few are, admitting to an agenda which is inherently hostile to mankind, but most, despite their rather clear anti-man agenda, continue to deny it. So I doubt event he most persuasive evidence will be enough to cause that sort of environmentalist to abandon what has proved such an effective propaganda tool.
POSTSCRIPT
I decided to, once again, skip the links within the article, and instead list all of my writings on environmentalism here:
If They Were Serious
A Thought on Oil Reserves
The Lie of Environmentalism
Knowing Our Limits
Funding
The Ends Justify the Means II
Transfats?
Very Quick and Simple Logic
Statistical Artifacts
Varieties of Environmentalists
A Thought on Nuclear Waste
Endangered Species
The World's Most Stupid Bureaucrat
Fire Up the SUV
A Brief Comment on Oil
G-d Save Us From Simple Solutions
Why I Doubt Peak Oil Predicitons
A New Fairy Tale
Some Global Warming Links
A Thought On Solar Energy
Several Convenient Untruths
Rejecting "Peak Oil"
Safe Nuclear Power
Organic Absurdities
A Question For Those Worried About Climate Change
Honest Environmentalists?
Passing Thought on Green Energy
Sampling Changes and Fictional Trends
Pet Peeve
Once Again, Confused by Our Own Data
Running an Economy on Compost, Saw Grass and Solar Cells
Twice in a Row
Historic Myopia
More About the Hockey Stick Graph
The Failure of Peer Review
The High Cost of Cap and Trade
Allergies
A Dearth of Common Sense
How to "Grow the Economy"
Subsidizing Irresponsibility and Poor Planning
Again Improving Science Misleads
The Perfect Model
How Green is Green Energy?
Debunking "Debunking Global Cooling"
More On Biodeisel
Obviously, I mixed those on AGW with others of a more general nature (including some not specifically on environmentalism, but on the misuse of statistics, which lies at the heart of so many environmentalist fallacies). Hopefully the titles will make clean which is which.