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The urgent need to stabilise
population numbers
Jenny Goldie
Sustainable Population Australia inc
[email protected]
Global population
Global population 6.48 billion
Still grows by over 70 million a year
9 billion by 2050 – up to 12 billion
Most future growth in developing world
Growth variable – TFR 1.2 – 8
Many low pop growth countries wealthy
Most high pop growth countries poor
Barriers to further growth
Ecosystem health
Food production
Climate change
Peak Oil
Ecosystem health
Millennium Ecosystem Assessment:
• Humans have changed ecosystems more
rapidly and extensively in the last 50 years
than in any other period
• Ecosystem changes that have contributed
substantial net gains in human well-being and
economic development have been achieved
at growing costs in the form of degradation of
other services.
Ecosystem Health
Millennium Ecosystem Assessment:
• The degradation of ecosystem services could
grow significantly worse during the first half
of this century and is a barrier to achieving
the UN Millennium Development Goals.
• The challenge of reversing the degradation of
ecosystems while meeting increasing
demands can be met but require significant
policy and institutional changes.
Food production
• 800 million undernourished (hungry) with no
money to buy available food
• 3 billion malnourished
• Many countries not self-sufficient in food
• Total calorie production has kept pace with
population growth thanks to oil crops, but…
• per capita grain production has fallen for past
two decades (380 to 330 kgs/person)
Food production
• Yields still increasing but rate declining
• Land gained from deforestation about equal
to land lost to houses, roads & degradation
• 10 m hectares annually lost to soil erosion
• 10m hectares annually lost to salinisation
• Quarter of all arable land - declining
Food production
• Little good land left to farm (maybe Brazil)
• Cannot expect dramatic gains in yield
• Diminishing returns (extra fertiliser doesn’t
increase yields after a point)
• Falling water-tables from over-pumping
• Loss of farmland to ethanol
• Loss of cropland and rangeland to erosion
Food production
• Average grainland world wide:
0.23h in 1950
0.11h in 2000
0.07h in 2050 (at 9b and no loss of land)
• Decline in resources will lead to drop in living
standards and ultimately conflict
• “World food security could begin to eclipse
terrorism as the over-riding concern of
governments.” - Brown
• Falling water tables, drying rivers and
polluted water
• Annual grain harvests dropping since 1998
• 1.4 b people - still growing 0.6% a year
• Grain deficit (demand minus supply) 37.5 m
tonnes this year
• Imported $US14.3b farm produce half 2004
• Will soon import 30-50 m tonnes annually
Climate change
UNFPA (2001)
• increased severity and intensity of storms
• flooding and soil erosion
• accelerate the extinction of plants and
• shift agricultural zones
• threat to public health through increased
water stress and tropical disease
Climate change
• 0.7 degrees C. increase last century
• 1.4 – 5.8 degrees C. this century
• Both adverse and beneficial impacts
• Richer countries (temperate) enjoy
some beneficial effects
• Poorer countries (tropical) endure
adverse effects
Climate change
Effects of increased CO2 in the field
Potential losses from pests and disease
Spatial variability in crop losses
Effects of extreme climate events on
crops and livestock
Climate change
• Global warming has already cut rice harvests
by 10% for every 1 degree inc in night-time
• Rice production needs to increase 1%
annually to keep pace with demand….but
• 3.5 degree rise this century would see rice
yields decline another 30%
• Modern strains of rice may be resistant to
rising temperatures (IRRI – Philippines)
Climate change
Rising seas
• Half metre rise by 2100 will double number of
people affected by flooding (to 100 m)
• Coastal land and mangroves damaged
• Severe implications for fish-stocks from a
warming ocean (wind strength and ocean
circulation will affect breeding and migration
Peak Oil
Global supplies will peak soon (Simmons)
Oil effectively gone in 40 years
Current production 85 mbd - 75 mbd in 2015
Faster oil extracted, faster pressure dissipated
Overproduction leads to production collapse
New fields often poor quality (Kazakhstan)
Tar sands extraction very energy-intensive
Peak Oil
• Higher energy prices
• Higher prices of transported goods eg food
• Air travel and tourism adversely affected
• Recession likely with inflation and high
unemployment and consumer debt
• Plastics, medicines, packaging, synthetic
fabrics, road surfaces, cosmetics, detergents,
fertilisers will become scarcer
Peak Oil
Implications for agriculture:
• 70% water used for irrigation
• More expensive to pump water around
• Uneconomic to pump from deep aquifers
• Land converted back to dryland farms,
meaning less food available
• More expensive to drive modern machinery
• Fertilisers and pesticides increasingly
expensive, meaning lower yields
• Increased demand for food and water as
population grows
• Yet less food and water available because of
higher energy costs
• Already 1.1b without adequate water and
2.4m without adequate sanitation
• Need to stabilise atmosphere with 60%
reduction in GGE
• Urgent need to reduce per capita demand in
rich countries but lift poor out of poverty
• Need to lift yields to feed more people at very
time it will be difficult to do so
• Ecosystems already stressed so cannot take
on new land to farm
• May need to revert farms to forest to retain
ecosystem services
• Technology can help but will not allow
• Only solution: rapid stabilisation then
reduction of population