Rob Wilson

Thanks to Andy Dugmore, Richard Tipping and Dave Stahle for input/advice

Environmental ChangeA varying balance between:

Anthropogenic Influences

Climatic Influences

Temperature Precipitation

Environmental Change and SocietyA two-way process of

Environmental change influences Society

Societal change influences the environment

Teasing out and identify between these two directional processes may not always be straightforward

Cultural change - Theories“Cultural Determinism”

Culture alone determines culture.

“Environmental determinism” Human culture is determined by the

environment.

“Possiblism”Compromise: The natural environment

influences the range of available (possible) human choices.

Climate - SocietyHuman populations adapt to the climate:

• We minimize the downside

• We maximise the opportunities

• It shapes our:

• Agriculture

• Economy

• Culture

• Way of life

We are accustomed to the

“mean climate”

Human population is also stressed by the

climate :• Weather extremes:

• Drought & Flood

• Heat & cold waves

• Storms

• Climate change:

• Natural variability

• Human induced changes

We are sensitive to

“climate

variability”

But …

Future climate change……

Fi gur e TS. 29

IPCC 2007

So….

can we learn about our future by studying the past?

We always say we can, but there are likely no climatic analogues over the past 8000 years equivalent to the next 50 years?

Also – the current geopolitical situation is radically different than any period in the past

Jared Diamond (2005)Collapse: How Societies Choose to Fail or Succeed

Defined a five-point framework of factors that may contribute to environmental related societal “collapse”

1.Anthropogenic environmental damage For example deforestation contributing to severe environmental damage

2.Climate change Disappearance of the Norse from Greenland and the Anasazi from the American Southwest

3.Hostile neighbours Societies may be able to hold off neighbouring societies as long as they are strong, but succumb when they weaken due to either 1 or 2

4.Decreased support by friendly neighbours If one society collapses, it may no longer supply things which are essential for nearby societies – the collapse of the friendly society may be due to 1 or 2

Diamond’s Fifth PointA societies response to problems is critical,

and will determine whether or not the society survives

So for us today – the threats are: Global climate change War/conflict Energy availability Economic dislocation…..etc

nearly all are related to human choice rather than natural causes

Lawler 2010

Collapse vs. Change

In reality, cultures do no necessarily “collapse”

Total collapse is very rare

Rather cultures change and adjustMigration Change in resource utilisationPolitical changeLife style change

Climate - environment – Societylessons from the past

How have cultures responded to short/longer term climate/environmental changes?

NB. It is crucial to combine detailed and well-dated palaeoclimate and historical/archaeological records.As we go back through Holocene – quality of records

degrade

To some Case Studies……..Can be thought of as “completed experiments”

through which causal factors can be examined

Tree-ring record of US droughtMEGA DROUGHTS

Cook et al. (2004)

The Dust Bowl DroughtInstrumental PDSI Tree-Ring Reconstructed PDSI

Coast-to-coast dryness

Worst drought in 350 years

Impact & drought itself aggravated by poor land use practices?

largest environmental migration in US history

Dalhart, Texas, 1938

1931-1940 1931-1940

Stahle pers comm

The 16th Century MegadroughtThe most severe-sustained North American drought of the past 500 years?

50-years of incipient to severe drought in Mexico, 1540-1589

Worst 30-years = 1560-1589Demographic catastropheCocoliztli: hemorrhagic fever

1560-1589

Sequence of climatic extremes, 4 largest epidemics.Disease agent unknown, leading hypothesis: rodentreservoir amplified by climate & ecological extremes.

Stahle pers comm

Lost Colony & Jamestown Droughts

Stahle, D. et al. 1998. The Lost Colony and Jamestown Droughts. Science 280(5363): 564-567.

Great Pueblo Drought“Great Drought” 1272-1298 AD (~26 years)

Square Tower HouseMesa Verde, Colorado

1276-1297

NoData

• Late 13th Century drought and apparent de-population of large areas of Colorado Plateau.

• Cause of Anasazi abandonment still debated • drought, over-exploitation, warfare, religion• we will never truly know, Cook et al. (2004), Benson et al. (2006)

The Norse Greenland settlement

As cumulative temperatures decline, marine component of Norse diet increases (up to 80%)

Records of diet through time show adaptation to changing climate

A potential ‘resilience trap’?The marine-focussed adaptation waseffective over century time scales butWith resultant loss in resilience?

Dugmore pers comm; Dugmore et al. 2007

Double exposure? Plague may have reached Greenland in 15th century; it certainly caused the collapse of the Norwegian economy ( & market for Greenland ivory)

Triple exposure

?Inuit

contacts: source of

conflict, or source of

trade goods (furs)?

THE TRANSITION TO AGRICULTURE IN THE BRITISH ISLES

THE TRANSITION TO AGRICULTURE IN THE BRITISH ISLES

Major cultural change - 6000 cal BP

Long-standing debate over how this occurred:

the early Neolithic ‘package’ (farming, pottery, monumental architecture) was somehow absorbed by Mesolithic hunter-gatherers described as a ‘process’ to blur the need for causal

factors and emphasise cultural determinism

rapid change made by incoming continental farmers

Tipping pers comm

THE TRANSITION TO AGRICULTURE IN THE BRITISH ISLES

Bayesian dating now shows an abrupt beginning at c. 6000 cal BP

Suggests an ‘event’ rather than a process

begs the questions why the invasion?why then?

Tipping pers comm

Answers??Population pressure on continent?

no evidence for this

Climate downturn c. 6400 to 5800 cal BP but what was the mechanism?Climatic downturn resulting in failure of wild

resources for hunter-gatherers – increasing unpredictability

Concurrent decline in tree populations (Elm, pine etc)

Climatic downturn also affects continental farmers Migration some west to the British Isles

Agriculture - more reliable food resource – abandonment of hunting-gathering

Tipping pers comm

THE TRANSITION TO AGRICULTURE IN THE BRITISH ISLES

What is needed – ongoing research

Better resolved reconstructions of Past climate Vegetation change – including wild resources

Putting archaeological record on the same time-line to examine Cultural/societal changes Diets of hunter-gatherers vs. later Neolithic

cultures

Leverhulme Trust Project - RELIC:Reconstructing 8000 years of Environmental and Landscape change in the Cairngorms

Pine MacrofossilsLong TR chronology

Palynology

Limnology Geochemical analysis

Comparison to regional archaeological record

Wilson and Edwards (2010-2012)

Summary - Environmental/Societal ChangeSocieties rarely collapse

They do however change Dependent on their overall resilience

A key point is to understand the circumstances when environment change may have an effectthis is highly conditional on the social-political-

economic context

Small changes may have significant effects on a sensitised system, whereas in other contexts dramatic changes may have comparatively limited effects

Finally…………………..Moments of Crisis: From Coincidence to Hypothesis in Scottish

Prehistory

One-day ‘round table’ Workshop: Saturday January 22nd 2011

Sponsored by Scottish Alliance for Geoscience, Environment & Society (SAGES) / Scottish Archaeological Research Framework (ScARF) Collaboration

Organised: Richard Tipping (Stirling University), Bob McCulloch (Stirling University), Jeff Sanders (ScARF) and Rob Wilson (St. Andrews University).