posted on Sep, 21 2013 @ 11:00 AM
... in Germany, nurtured by the northerly warmth of atlantic sea
- Micheal E. Mann
The general assertion that the climate change Earth went through over the last 150 years is 'unprecedented' and humanity has never before experienced
similiar climate conditions, wether the magnitude or the rate of change, is not only unscientific it is simply not true.
Climate is always experienced regionally and in the last 2,000 years entire continents went through rapid changes, prolonged periods with
substantially warmer or cooler temperatures than observed in the last century were rather the norm than the exception. The idea that pre-industrial
climate has always been 'stable' and only began to change recently does not hold up against the historical perspective.
The Pages2k study (Past Global Changes) is the most comprehensive evaluation to date of temperature change at the surface of Earth’s continents over
the past one to two thousand years. The regional focus on the past 2,000 years is significant for two reasons.
First, climate change at that scale is more relevant to societies and ecosystems than global averages. And second, “regional scale differences help
us to understand how the climate system works, and that information helps to improve the models used to project future climate”.
Temperatures did not fluctuate uniformly among all regions at multi-decadal to centennial scales. For example, there were no globally synchronous
multi-decadal warm or cold intervals that define a worldwide Medieval Warm Period or Little Ice Age.
- The period from around 830 to 1100 CE generally encompassed a sustained warm interval in all four Northern Hemisphere regions. In contrast, in South
America and Australasia, a sustained warm period occurred later, from around 1160 to 1370 CE.
- The transition to colder regional climates between 1200 and 1500 CE is evident earlier in the Arctic, Europe and Asia than in North America or the
- By around 1580 CE all regions except Antarctica entered a protracted, multi-centennial cold period, which prevailed until late in the 19th
- Cooler 30-year periods between the years 830 and 1910 CE were particularly pronounced during times of weak solar activity and strong tropical
volcanic eruptions. Both phenomena often occurred simultaneously. This demonstrates how temperature changes over large regions are related to changes
in climate-forcing mechanisms. Future climate can be expected to respond to such forcings in similar ways.
In Europe, slightly higher reconstructed temperatures were registered in A.D. 741–770, and the interval from A.D. 21–80 was substantially warmer
than 1971–2000. Antarctica was probably warmer than 1971–2000 for a time period as recent as A.D. 1671–1700, and the entire period from
141–1250 was warmer than 1971–2000.
A chart from a new study of temperature changes over the continents through 2,000 years. The colors denote the extent of warming or cooling (key at
right). The bars denote 30-year periods during which the mean temperature was calculated.
Paleoclimatology is rapidly evolving field, but is not yet an exact science. The findings of more recent paleo-reconstructions can vary considerably
compared to previous studies. One example are Europe's climate changes of the past. When exactly did conditions change so much that Agriculture was no
longer possible at altitudes higher than today.
Mediterranean vegetation able to grow in Southern Germany until 1300 AD retreated much further south. As is evident on all other continents, Europe
too has experienced many different, sometimes rapidly changing climate regimes over the course of the past two millennia.
Medieval Climatic Optimum
Europe experienced, on the whole, relatively mild climate conditions during the earliest centuries of the second millennium (i.e., the early Medieval
period). Agriculture was possible at higher latitudes (and higher elevations in the mountains) than is currently possible inmany regions, and there
are numerous anecdotal reports of especially bountiful harvests (e.g., documented yields of grain) throughout Europe during this interval of time.
Grapes were grown in England several hundred kilometers north of their current limits of growth, and subtropical ﬂora such as ﬁg trees and olive
trees grew in regions of Europe (northern Italy and parts of Germany) well north of their current range.
Geological evidence indicates that mountain glaciers throughout Europe retreated substantially at this time, relative to the glacial advances of later
centuries. A host of historical documentary proxy information such as records of frost dates, freezing of water bodies, duration of snowcover, and
phenological evidence (e.g., the dates of ﬂowering of plants) indicates that severe winters were less frequent and less extreme at times during the
period from about 900–1300 AD in central Europe.
The changes of the past appear to be not so different from the change we're experiencing now. The question, however, how do we contribute to the
changes remains still unanswered.
What is wanted is not the will to believe, but the will to find out, which is the exact opposite.
edit on 21-9-2013 by talklikeapirat because: i'm just a treeamer