Background:
This casestudy takes us to Ancient India and one of the
earliest urban civilizations in the world - the Harappans. Whilst the origins
of the society is debated the Harappan society is thought to have existed from
around 3300 to 1300 BC in three phases (early, mature and late) and to have spread to cover a vast area (Fig 1) which
included parts of both Pakistan and India.
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| Fig. 1 The Harappan civilization covered a large geographical area from as far as Saurashtra and the Ganges- Jumna Doab. The settlement was bordered by the Himalayas in the North, the Arabian sea in the South and by Baluchistan in the West. However, it is debated whether these areas were inhabited at the same time or sequentially. (Source: Kings Academy) |
The ancient city was first discovered accidently by the
British in the mid 19th century and further excavations revealed a highly sophisticated
society. Evidence of this complex society was found in the form of: pottery,
ornaments, weaponry, bronze, clay figurines, uniform bricks, technologically
advanced crafted jewels and seals with inscriptions, early depictions of gods
and animals motifs (Fig 3). The settlement itself also suggested a highly developed
society as it had a high degree of urban planning (Fig 2) with separated private and
public area, houses with their own latrines, drinking wells, bathing houses, a
waste removal system, a sewage system that provided nearby agricultural farms
with fertilizer and the streets were built in a grid patterns with buildings
facing specific directions.
Archaeologists have also inferred that the Harappans were
a successful civilization from crafted artefacts and Harappan seals that were found in
places such as Mesopotamia and Oman, the result of trading that must have
occurred between these cities. The Harappans most likely traded in livestock, agricultural
produce, jewels, honey, raw materials and crafted ornaments such as ivory beads.
It is thought that a ruling elite may have controlled a widespread trade
network and that they ruled with religion as opposed to with military as no Harappan art
glorified warfare and, unlike other urban cities during this period there was evidence
of different classes and occupations. Radio carbon dating showed that due to
trade and advanced craft technology the civilisation experienced a peak
in urban growth and as a result was a major economic centre in 26-1900 BC with new settlements emerging in surrounding areas. The high craftsmanship of the Harappans and the
fact that the city systems and material wealth were found across these sites
suggests a regularity of the civilization spatially and temporally.
However, as still little is known about the Harappan
Civilization- including its exact origins, its un-deciphered script and sudden disappearance- the ancient city has become something of a mystery and of great interest to archaeologists.
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| Fig 2. Mohenjo-Daro a city complex of the Harappan Civilization (Source: National Geographic) |
The Harappans are thought to have started declining in
1800BC with the main cities being completely abandoned by 1500BC. This decline was due to the Harappans moving away from their cities to become mixed with nearby villages and less developed cultures until the 'Harappan culture' effectively became extinct. So how did this great
civilization decline? Two theories have been put forth as the possible causes
for the reduced density and number of sites of the Harappans– conflict and natural disasters…
Theory 1 - Attack of the Aryans!
One popular theory that emerged is that the Harappan
cities were invaded by hill raiders or (more commonly) the Aryans. This theory was
presented by Wheeler in 1953 who had inferred an attack from finding 37 skeletons that
date to the Indus Civilization at the sites and had previous knowledge that around 1500BC the Aryans were
conquering other cities. However this theory is now widely discredited as no
site indicated damage from an attack and the belief that if the Aryans had
invaded they would have enforced their own belief system - when in reality the
continuation of the Harappans’ religion, technology and societal organisation
indicates that a conquest did not occur. Moreover, other studies suggest a gap
between the end of the Harappans and the arrival of the Aryans.
On another hand, Kenoyer believes that the decline of the city was
due to a rising population which caused stresses being placed on
dwindling water sources, the economy and political strife. This meant societal organisation
became harder for the ruling elite which led to a drastic change in society. However, this was in
part due to changes in water supply and so the environmental changes offer a
more probable primary explanation for the Harappans' decline.
Theory 2 – A Natural Disaster!
The more plausible theory on the Indus collapse is that a
change in environmental conditions put pressure on society which eventually led
to people moving away to the countryside and into areas such as Gujarat, Punjab
and Uttar Pradesh whilst the old Harappan settlements became ghost towns. Archaeologists believe that changes to water
supply are to blame- although it should be noted that as the region regularly experienced
floods (seen by silt deposits) they had built embankments and foundations that
were higher than the water level which provided them with a degree of
resilience. Nonetheless, 2 different authors give their views on what may have occurred:
1. G.F. Dales (1966) states that the Harappan collapse is the result of floods. Whilst he acknowledges that silt deposits and slumping brinks indicate that the city
is used to dealing with floods he argues that the regular overflow
from the river was on a much larger scale and this was the source of the city’s
demise. Tectonic activity (seen by faulting in
rocks) induced an upheaval in Sehwan which altered the Indus River's flow as a
build up of mud blocked the rivers path to the sea and instead made water fill up in a reservoir. This would
have flooded settlements as, despite the protective measures built,
water may have overflowed from the reservoir’s natural dam. Moreover, this
flooding is thought to have been periodic and occurred at least 5 times and so
as the Harappans rebuilt foundations over sinking and decaying soil their resilience
to flooding fell. Thus after the 3rd phase of Harappan society there
came a squatter phase where the city degenerated from one with highly technical architecture
and artefacts to one with simple pottery, plain seals and broken brick housing. The
population eventually left the area to Gujarat as the devastation from sequential flooding meant a lower quality of life for the Harappans.
2. L.Giosan et al (2011) found that the civilisation grew and prospered in 4500BC
when a stable period in the late Holocene meant Himalayan rivers stopped
incising and reduced sediment deposition downstream. This in turn reduced the intensity of floods and allowed the Harappans to intensively farm land and increase output.
However, during a weaker monsoon rivers ran dry as
monsoonal rivers were no longer active and land became more arid.
This placed food insecurity on the Harappans as farming practices failed and output
could on longer sustain the growing urban settlement. Food and water stresses
made the civilization scale down and move away. Evidence for these changes correlate
with the rise in settlements in regions where a moist monsoon was occurring (e.g. Haryana, Punjab) and forced farmers to diversify their crops.
So what caused these environmental shifts?
Other than the possibility of tectonics as discussed in
Dales’ article, changes to the Pacific Ocean and solar variability may be to
blame.
The summer Indian monsoon was vital for the Harappans as
they provided the city with a reliable supply of water for domestic and agricultural
uses. During 9000-3000BP insolation reduced in the Northern Hemisphere and meant
the Pacific’s sea-surface temperature decreased and so ENSO events were much stronger.
Evidence showed that the region became more arid and there was a particular
pronounced drought at 4200BP.The region continued becoming more arid and this
presented problems with water supply which may have contributed- among other
factors- to the Harappans’ desertion. Oxygen isotopes from plankton also back
the theory that a significant change in 4200BP led to reduced river flow from
the Indus and variability in precipitation over Asia. The drought event fluctuated
between 200 and 800yrs which also correlates with findings of cosmogenic 14C
indicating that a change in solar variability is the reason for the changes
seen in precipitation and aridity.
However, the difference in timings of increasing aridity and
the phases in Harappan history suggest that whilst these environmental conditions
may have hindered development they are not the sole cause as a societal
collapse is unlikely to the effect of a single event. Moreover, an article by
Enzel (1999) goes further stating that inferred water levels from lake sediments
collected from Lunkaransar (a lake created when water tables are above ground)
indicate a shallow lake during the early Holocene that rose rapidly in 6300 14C
yrs BP and fell again drastically after 1000yrs. The sudden decrease in lake
levels may be explained y changes in vegetation and precipitation but these
changes were not uncommon and the conditions were in fact similar to present. Thus
this sequence suggests there was no link between the rise and fall of the
Harappans and that the major drought event –which happened 1500yrs earlier- had
caused their collapse. However, this article does not seem to consider wider
precipitation patterns and changes to the monsoon and local rivers which have
also been considered as factors for the Harappan decline.
Therefore, of all the theories proposed changes to the
natural environment seem to be the most probable cause for the collapse. This is
in light of the fact that there is not enough evidence to support the Aryan
invasion theory and correlating evidence
from other civilizations such as the Sumer Empire also show a sharp decline in society
due to drought caused by changes to the climate during the same period. These environmental
conditions most likely placed stresses on the ancient societies by reducing
food and water security which in turn probably led to secondary factors such as
strike, societal problems, the degradation of the city and eventual movement away
from Harappa. The changes to the monsoon
(similar to the Australian casestudy) seem to have majorly impacted the
society. Looking forward this is worrying as many societies still heavily rely
on the monsoon for water security, for agricultural production for food
security and as a major source of income (e.g. India gained $39billion in 2013for agricultural exports). Thus will climate change negatively impact the reliability
of monsoons? Will farming methods have to change to deal with changes? Will
these changes be done in time? And will future societies collapse if they can’t
cope?
Feel free to comment below what you think will happen…
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| Fig. 3 - The intricate and famous Harappan seals (Source: Tes) |
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