Transcript What Went On When it Got Warm?

What Went On When it Got
Warm?
Examining the
Roman Warm Period
300 BCE-300 CE
Carole L. Crumley
Stockholm Resilience Centre
IHOPE
Integrated History and Future of People on Earth
Goals of IHOPE:
Map the record of biophysical and human history
• Query correlations: question methods, use multiple lines of evidence
• Expect multiple causation
• Facilitate interdisciplinary cooperation
Understand the dynamics of linked human/Earth history
• Calculate rates of change in system variables
• Calibrate models against historic data
• What are the emergent properties?
Examine options for the future of humanity
• What “lessons” emerge? Examples:
• Path dependence, initial conditions, the multiple roles of diversity
• Paleoengineering: enduring solutions to enduring problems
IHOPE Case Studies
• Culture and Economy of SW USA
Native American polities and the
Drought of the 1300s CE
• Environment And Society in the Maya
region of Central America 1000 BCE to
1000 CE
• Environment and Society in Europe
from 1000 BCE to 1000 CE
Bracketing the Roman Warm Period
When and Where?
• Temporal extent: The Roman
Warm Period occurred between ca.
300 BCE and 300 CE; the
1000BCE – 1000CE time frame
captures colder, wetter periods on
either side
• Spatial extent: E-W From the Ural
mountains to the Atlantic Ocean,
N-S from Scandinavia to North
Africa
• We have only begun to investigate
its global extent; we plan to study
teleconnections to adjacent regions
and around the globe
Study Area
How is the Roman Warm Period Defined?
Greenland Ice Core
Estimated Temperature
•
A warm, stable period lasting ca. 600
years, roughly paralleling Roman
hegemony
•
Camp Century shows the clearest
signal, but record complicated by
changes in ice sheet elevation
•
More recent Greenland temperature
reconstructions also show high
temperatures during Roman period
•
Rapid decline begins after 100 AD,
falling to the Vandal Minimum, which
coincides with the Migration Period
(“the Dark Ages”)
Alley QSR 2000
Climate History
the Northern Hemisphere and Europe
Land Use and Emission History
•
The Bronze Age began 3300BC in the
Middle East, thence to India, Europe,
China, and Korea
•
The Iron Age began in the Near East
1300BC, thence to India and Europe,
China, Japan; sub-Saharan Africans
independently invented iron technology
•
Roman period industrial production was
widespread (ceramics, metals, glass, etc)
•
On three continents, deforestation for
metallurgy, agriculture and wood
products began before the Iron Age and
accelerated in the Roman period
Estimated Position of the Temperate-Subtropical
Ecotone
900-500 BCE
300 BCE-300 CE
Roman Warm Period
500 CE-900 CE
Vandal Minimum
Crumley EA 3:3, 1993
The European Iron Age
• Hallstatt (ca. 1000-480 BCE) which
offers evidence of great wealth in an elite
society with long-distance contacts and
influence
• La Tène (ca. 480-15 BCE) which ushers
in a revolution (regime shift?) in social
and political organization and settlement,
with an emblematic decorative style
The Power of Rome
At its greatest extent, the Roman Empire
• controlled the Mediterranean Sea and contiguous lands
• covered nearly six million square kilometers
• had an estimated population of sixty-five million people
• a quarter of the planet’s population was under the sway of Rome
Roman Imperial
Management
and Climate Change
• mono-cropping: many regions were forced to
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produce grain to feed cities
erosion, loss of fertility: result of practices to
increase short-term yields
deforestation: the need for agricultural land and
for ships’ timber
erratic climate devastated harvests after ca. AD 270
subtropical species: vulnerable in temperate regions
farmland abandoned due to high taxes, low yields
and without maintenance reverted to scrub
and forest
The Migration Period
“The Vandal Event”
climatologists
“The Dark Ages”
Petrarch (14th c.)
“Barbarian Invasions”
J. J. Bury
300-500 CE: Germanic peoples
500-700 CE: Slavic and Arabic peoples
700-900 CE: Magyar, Turkic, and Viking peoples
Isotopic Record
Lake Holzmaar, Western Germany
High human impact
through Iron Age and
Roman period disappears
with transition into
Migration period. Isotopic
record suggests that this
is a response to colder
and/or wetter climatic
conditions causing a
retreat of people from the
catchment area.
Lucke et al 2003
Fluvial Geomorphology
Lahn River, West-Central Germany
Urz, 2002
Peaks in tree trunk deposition coincide with and increased fluvial
activity, climate ‘deterioration’ in the Migration period.
Questions for Study
• What is the chronology of the Roman Warm Period in Europe?
• What are the drivers of the RWP?
NAO? Other?
Are there anthropogenic drivers?
• Is the RWP confined to the Mediterranean and temperate Europe?
What characterizes the period on other continents?
(Gulf of Mexico/Yucatan Peninsula, Eurasian steppe)
• What is the nature of transitional periods that preceded and
followed the RWP?
• It appears that the beginning of the Roman Warm Period may have
occurred in a couple human generations (Dansgaard-Oeschger?)
• An inquest on collapse: κ to Ω to α in a coupled CAS
The Roman Warm Period
and Global Change Studies
• plentiful data from both qualitative and quantitative disciplines
• a period about which relatively little environmental data are available,
despite abundant political, economic, and cultural data
• possibilities for scale-up to N hemisphere or global
• potential for modeling future ecological and cultural refugia in a warming
world
• an enthusiastic scholarly community, representing social sciences,
humanities, and biophysical sciences
• popular appeal, offering didactic opportunities