Transcript Document
Putting People in the Picture: Population, Development and the Environment in the 21
st
Century
Source: National Geographic 2011 Global population trends Components of change The demographic transition
Lecture learning objectives
1. Appreciate the scale and dimensions of global population growth 2. Explore the links between population, the environment and development
Population growth through history
8000 7000 6000 5000 4000 3000 2000 1000 0
BC AD
For most of human history, global population did not exceed 10 million 1804: 1 billion 1927: 2 billion (123 years later) 1959: 3 billion (32 years later) 1974: 4 billion (15 years later) 1987: 5 billion (13 years later) 1998: 6 billion (11 years later) 2011: 7 billion (13 years later)
Year
Current world population increase
On 31/10/2012 the world’s population reached 7 billion It is currently growing at around 2.5 people per second 78 million people per year
Time interval
Year Day Hour Second
Births
133,201,704 364,936 15,206 4.2
Deaths
55,490,538 152,029 6,335 1.8
Natural increase
77,711,166 212,907 8,871 2.5
During this lecture 15,206 babies will be born and 6,335 people will die. The global population will increase by 8,871.
How many people were alive when you were born?
http://www.ined.fr/en/everything_about_population/world_p opulation_me/
Continuing but slowing growth
• Nearly all growth - 97 of every 100 people - is occurring in LDCs
Demographic Components of Change P
t+n
= P
t
+ (B – D) {+ (I – O)}
Where P t+n is population at time t plus n years P t is population at time t B is births occurring between t and t+n D is deaths occurring between t and t+n
I represents gains from immigration O represents losses through emigration
160,000 140,000 120,000 100,000 80,000 60,000 40,000 20,000 0 Births Deaths Natural Increase 20,000 18,000 16,000 14,000 12,000 10,000 8,000 6,000 4,000 2,000 0 Births Deaths 140,000 120,000 100,000 80,000 60,000 40,000 20,000 0 Births Deaths
•
Why did global population growth explode in the 20 th Century?
•
Why is the rate of global population growth decreasing?
•
When/if will global population stabilise?
The demographic transition model
Describes the transition from traditional societies in which birth and death rates are high but in balance, through epochs of rapid population growth, to the situation characteristic of modern, industrial societies where fertility and mortality come back into equilibrium at new low levels • Descriptive device - empirical observations of actual countries • Explanatory theory - attempts to explain why changes occur as they do • Predictive model - allows timing of transition to be predicted See e.g. Thompson 1927, Notestein 1945, Dyson 2012
The demographic transition model
Mortality decline Population growth Fertility decline Urbanisation Transition from a young, rural, fluctuating population through a period of rapid growth towards an old, urban population that is stable or in decline Ageing
Associated Transitions
Mobility Occupational Educational Political Gender equity After Dyson 2012
Testing the DTM…
– www.bit.ly/1snrk8x – www.bit.ly/1nk5t2c – www.bit.ly/1nk6ozE
21 19 17 15 13 11 9 7 5 25 20 15 10 5 0 Crude Birth Rate Crude Death Rate Population 40 000 35 000 30 000 25 000 20 000 15 000 10 000 5 000 0
Year
Crude Birth Rate Crude Death Rate Population 70 000 60 000 50 000 40 000 30 000 20 000 10 000 0
Year
45 40 35 30 25 20 15 10 5 0
Year
65 55 45 35 25 15 5 Crude Birth Rate Crude Death Rate Population Crude Birth Rate Crude Death Rate Population 80 000 70 000 60 000 50 000 40 000 30 000 20 000 10 000 0
Year
80 000 70 000 60 000 50 000 40 000 30 000 20 000 10 000 0
The end of world population growth…
35 000 000 Medium variant Low variant High variant Constant variant 30 000 000 25 000 000 20 000 000 15 000 000 10 000 000 5 000 000 0 Source: United Nations, Department of Economic and Social Affairs, Population Division (2011): World Population Prospects: The 2012 Revision. New York
Bifurcation into Two Global Demographic Categories
Low growth countries with rapid ageing Italy 57 million 41 million (-28%) 33.3% 65+; median age 52.5
Japan 127 million 105 (-17%) 37.8% 65+; median age 52.3
High growth countries with high fertility and low proportions of older people India 1.03 billion 1,63 billion (+58%) (13.7% 65+); Nigeria 158 illion 289 (+82%) (6.2% 65+)
100+ 90-94 80-84 70-74 60-64 50-54 40-44 30-34 20-24 10-14 0-4
Males Females
1950 2010 2050
Population (000s)
• MDCs • Population ageing • LDCs • Youth bulge (young age structure) • Demographic dividend (Transitional age structure)
Per cent Urban Population: More and Less Developed Regions
Key Facts
Mid 2009, no. of people in urban areas (3.42 billion) had surpassed no. of people in rural areas (3.4.1 billion) By 2050 this will rise to 6.29 billion – absorbing the entire world’s population growth of 2.32 billion people Key Facts MDCs (74.9%) are more urbanised than LDCs (44.6%) Both will become more urbanised by 2050 By 2050 LDCs will account for 82.5% of the world’s urban population, up from 73.0% in 2009, and 41.5% in 1950.
Source: World Urbanisation Prospects 2009
Can the environment support an increase in global living standards with a growing population?
Population, development and the environment
Since 1990: - Population has grown by a factor 1.4 (5.3 billion to 7.2) - Life expectancy has increased from 64.8 to 70.0 years - Number of people undernourished has declined from 1 billion (18.6%) to 868 million (12.5%)
BUT
- Global forest cover has declined from 4.2-4.0 million hectares - Carbon emissions have increased from 21,523 to 32,578 million metric tonnes (factor 1.5) - Wild vertebrate species have fallen by more that one third (31%) since the 1970s (GBO-3)
What do you think?
Is population growth:
Good for the environment Bad for the environment Has no impact on the environment
Is population growth:
The most important factor contributing to environmental degradation One of a many factors contributing to environmental degradation Not important at all
The Doomsters…
The idea that we can just keep growing forever on a finite planet is totally imbecilic…. Simon, a professor of junk mail marketing, and his kind, think technology will solve everything…. We can use up the Earth then we can just jump into spaceships and fly somewhere else….
Technology does nothing to solve problems of biodiversity or living space or arable cropland…. Fresh water and arable cropland are finite non-renewable resources….
We are already far beyond what we can support sustainably… Sir David Attenborough Dr. Paul R. Ehrlich We are a plague on the Earth. It’s coming home to roost over the next 50 years or so. It’s not just climate change; it’s sheer space, places to grow food for this enormous horde.
Either we limit our population growth or the natural world will do it for us, and the natural world is doing it for us right now
Malthus: The Principle of Population
Essay on the Principle of Population as it affects the future improvement of society; with remarks on the speculations of Mr Godwin, M Condercet,
and other writers (1798) Thomas Malthus
• In the natural order population growth will outstrip the food supply and the lack of food will ultimately put a stop to the increase of people • Humans are impelled to increase and if unchecked, the population will grow exponentially (2,4,8,16) • The resource base to support the population grows arithmetically (1,2,3,4)
Malthusian Checks
• • Positive checks – – Increase the death rate hunger, disease, warfare Preventative checks – – Lower the birth rate Control fertility through sexual restraint outside and within marriage (not contraceptives) • Ultimate consequence of population growth is poverty and misery
Easter Island
Once covered by palm forests but treeless at time of European arrival Settled 500 BC - subsistence needs easily met - carving and moving statues Forest reduction from 900 AD and palm forest gone by 1400. Statues carved 1100 and 1500….transported using trees as rollers.
Loss of forest reduced water retention and led to soil erosion Population declined from 10,000 in 1500 to 2,000 at time of European discovery in 1722.
Population growth degraded the environment to the point of collapse Exacerbated by introduction of European disease, sheep and eucalypts [Brander and Taylor (1998) The Simple Economics of Easter Island. A Ricardo/Malthus Model of Renewable Resource Use.
The American Economic Review
, Vol . 88, No.1, pp. 119-138.]
The Boomsters
Adding more people causes problems, but people are also the means to solve these problems. The main fuel to speed our progress is our stock of knowledge, and the brake is our lack of imagination. The ultimate resource is people – skilled, spirited, and hopeful people who will exert their wills and imaginations for their own benefit, and inevitably they will benefit not only themselves but the rest of us as well.
The Ultimate Resource, 1981, 1996, Princeton UP
Dr Julian Simon (1932-1998) Dr Bjorn Lomborg [Population] is not a great concern in most of the world right now... Yes, an extra person is an extra mouth to feed, but it's also two hands and a brain to work and to think, and it typically works out pretty even on those areas. Second ... we peaked in [terms of] percentage increase in the early 1960s; we peaked in absolute addition to the world in the early 1990s; and what we're seeing now in most developed-world [countries] is actually a decline in populations
The Skeptical Environmentalist, 2001, Cambridge UP
Ester Boserup(1910-1999)
The Conditions of Agricultural Growth: The Economics of Agrarian Change Under Population Pressure
• Argued that population growth is the major cause of agricultural change and that the principal mechanism of change is the intensification of land use through an increase in the frequency of cropping
Population growth is a stimulant...
• Boserup (cont.) – Success of the Green Revolution in Asia was (in part) a function of the high population densities – Africa?
• Julian Simon • • The Ultimate Resource Population growth is almost always beneficial for economic growth
Machakos, Kenya
Relatively dry and hilly area which experienced severe deforestation and soil erosion in the early colonial period from 1900 By 1930 concerned to be an environmental disaster with an impoverished population of small farmers/pastoralists Population increased from 240,000 (1930)to 1,393,000 (1989) (3% per annum) Introduced controls on stocking rates , forest clearance, terracing and water management Lead to intensification of farming (shorter fallow, wider variety of crops) Improvement in transport infrastructure and links to Nairobi Migration of men – off-farm Changing gender roles [Gould, W.T.S (2009) Population and development [electronic resource], New York : Routledge]
The ornucopians
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What do geographers think?
Population dynamics affect the environment through other variables such as culture, consumption levels, institutions, and technology • • More to population dynamics than population size and growth e.g. composition, household demographics Increasingly concerned with the impacts of the environment on populations!