2. - Center for Bioinformatics

Resolving Global Overpopulation
Chris Bystroff
Biology / Computer Science
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Overpopulation:
1. Discussing overpopulation is like putting a turd in the punchbowl
!
Why we tend to avoid the issue.
2. Are we smarter than a yeast?
!
Equations for population growth and decline.
3. Sustainability versus compassion.
!
Lifeboat ethics.
4. The road ahead.
!
Technologies and choices.
1. Discussing overpopulation is like putting a turd in
the punchbowl
Why we tend to avoid the issue.
3
Human population, the last 700 years
7
6
billions
5
4
3
2
1
1300
1400
1500
1600
1700
1800
1900
2000
overcrowding
extinctions
Wilson, Edward O. The diversity of Life, The Belknap Press of Harvard university press, Cambridge, Mass.1992.
loss of biodiversity
degradation of arable land
invasive species
What will come of this?
Disease
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War!
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Famine!
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How would you react?
Choose 1
1. Continue eating and ignore him/her.
2. Look at watch. Make excuse. Get out
of there as fast as possible.
3. Engage in an animated conversation
about the-end-of-life-as-we-know-it.
4. Reassure them that population is not a
problem.
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A typical reaction to bad news
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Cognitive dissonance
Cognitive Dissonance -- an uncomfortable feeling caused
by holding conflicting ideas simultaneously.
How we react to dissonance
Level of
Dissonance
Music
Science
Human
reaction
low
twinkle twinkle
little star
basic
arithmetic
boring
medium
J.S. Bach
physics or
biology
interesting!
high
Anton
Schönberg
overpopulation
flee!!!
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reproductive instincts
se
s
leads to
ea
cr
guilt trip
Your brain on overpopulation
inhibits
ith
co
nfl
personal time
investment
other time
investments
s
ict
sw
demands
tes
s
wa
ie
reproductive
austerity
irresolvable
conflicts
with
pe
perceived
as
ed
rci
ev
ibit
s
implies
as
inh
ved
political issue
de
personal
isolation
pl
cei
outside of the
mainstream
im
per
as
Discussing population
How should
overpopulation be
resolved?
Choose one.
(A) War.
(B) Disease.
(C) Famine.
✓(D) Other.
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How will overpopulation
be resolved?
Choose one.
✓(A) War.
✓(B) Disease.
✓(C) Famine.
(D) Other.
19
Are we smarter than a yeast?
Equations for population growth and decline.
20
Human population, the last 700 years
7
6
billions
5
4
3
2
1
1300
1400
1500
1600
1700
1800
1900
2000
Population growth is exponential given
constant conditions
N
r = birth rate - death rate
t1/2 = ln(2)/r
t1/2 = 70 years / %pop. incr.
22
Population decline is exponential given
constant conditions
N
If birth rate < death rate,
r<0
so ert < 1.
time
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boom/bust of isolated species
Yeast in 10% sugar solution
24
Michael Mills, Dept of Psychology, LMU
population (consumption)
Overshooting the carrying capacity
degrades the carrying capacity
carrying ca
theoretical upper limit
to carrying capacity
pacity
overshoot
degraded
carrying
capacity
Carrying capacity is the
amount of food (and other
resources) available to
support human life
sustainably. If resources
(such as wild fish) are
overused, they do not
recover as quckly,
degrading the carrying
capacity.
time
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Overshooting carrying
capacity by using nonrenewable water
NASA ASTER image of an approx. 557 mi² area of fields (1443 km²)
in Kansas which are watered from the Ogallala aquifer with center
pivot irrigation systems.
The Ogallala aquifer is being
depleted due to irrigation.
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Peak Oil
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People are stupid
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Goal of the United Nations
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ECOME - a simulated evolving consumption web
2
CO
2
CO
life
Bystroff C, DeLuca S, & McDaniel CN (2005) ECOME: A simple model for an evolving consumption web. IEEE Computational Systems
Bioinformatics Conference - Workshops 8-11 Aug. 2005 pp 260 - 261
• Species are measured in units of “biomass”
• Species can be autotrophs (green) or heterotrophs
(red)
• Plants catalyze CO2 --> CH
Plants grow proportional to biomass.
• The sun's maximum total input to the
food web is fixed.
All plants stop growing when the sum
total biomass ≥ sun limit
• Primary consumers (herbivores) get
biomass from plants
Secondary consumers (carnivores) get
biomass from other animals.
etc.
• All species also catalyze CH --> CO2.
i.e. All species lose biomass to respiration
and natural death, at a constant rate.
• Predator species collapse when prey is
scarce.
plant mass that is left
new mass needed to survive =
current mass * k.
• ...along with the prey species.
endangered
species
• Fed fraction grows
fed fraction
• Unfed fraction dies.
unfed fraction
• ...becomes CO2.
unfed fraction dies
...collapse follows on the next cycle.
• Hollings functions modify predator/prey
relationship. Predators can starve while
prey still exists, but is scarce.
Too small.
Predator
can't find it.
• Speciation.
http://www.bioinfo.rpi.edu/bystrc/ecome/local.mpeg
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Populations are inherently unstable
ECOME log(biomass) vs time.
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Boom/bust oscillations are
natural
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http://io.uwinnipeg.ca/~simmons/16cm05/1116/16popbio.htm
Conclusions from ECOME
experiment
• Animal populations are unstable.
• Ecosystems collapse if
– They are too small
– They evolve too slowly
– They have weak Hollings response
functions
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Can humans survive by
evolving faster?
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Cultural evolution is faster than evolution
Lamarckian evolution
+
+
Disuse
Use
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Collapses in past human societies
A short list
Mashkan-shapir
2300 BCE
Rome
400
Maya
800
Angkor
1220
Anasazi
1300
Ghana/Mali/Songhai
1300-1500
Europe
1348
Greenland Norse
1450
Easter Island
1860
Rwanda
1994
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Hypothesis
pop
time
55
Human population, the last 700 years
7
6
billions
5
4
3
2
1
1300
1400
1500
1600
1700
1800
1900
2000
Population growth is exponential given
constant conditions
r = birth rate - death rate
t1/2 = ln(2)/r
t1/2 = 70 years / %pop. incr.
57
13
12
Exponential projection: 13B by 2050
11
10
9
8
7
6
billion
5
4
3
2
1
2050
2000
1900
1800
1700
1600
1500
1400
1300
Single boom/bust
Yeast in 10% sugar solution
“Are humans smarter than yeast?”
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Michael Mills, Dept of Psychology, LMU
Malthus
"It is an obvious truth, which has been
taken notice of by many writers, that
population must always be kept down
to the level of the means of
subsistence; but no writer that the
Author recollects has inquired
particularly into the means by which
this level is effected..."
-- Thomas Malthus, 1798
An Essay on the Principle of
Population
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Worst case
pop
time
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Best case
pop
time
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Most likely scenario
pop
time
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All scenarios
pop
time
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65
66
pop
time
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Types of science
Who we are.
What we do
first.
What we then
do.
Natural
Scientists
Devise a
hypothesis.
Test it against
real data.
Social
scientists
Devise a
hypothesis.
Publish it.
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Q: Are we smarter than a yeast?
A: As individuals, Yes.
As a species, maybe not.
“A person is smart. People are dumb,
panicky, dangerous animals and you
know it.”
--Tommy Lee Jones character in “Men in Black”
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3. Sustainability versus compassion.
Lifeboat ethics.
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Conflicting ethics
bad
good
death
unsustainable
life
sustainable
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bad is good, good is bad
we are here
life
e
a bl
n
i
sta
u
s
un
ble
a
n
ai
ust
s
ble
a
n
tai
s
u
uns
death
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Lifeboat Ethics
Carrying capacity = number of people the boat (The Earth)
can hold safely.
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4. The road ahead.
Possible futures
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The road ahead
tim
e
carrying capacity
high tech
low tech
Environmental impact
Impact = Population * Affluence*Technology
I = P*A*T
dI/dt = AdP/dt + PdA/dt
where
dA/dt = change in affluence
dP/dt = change in population
If A is not changing much, then most of
the change in I is due to change in P.
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Demographic pyramids show changes in growth conditions
Population pyramid of the USA was bulging until the
1960s and has steadily slimmed since.
China had an extreme youth bulge until the 1960s,
when it sharply curbed partly as an effect of the onechild policy.
Angola: an unchanging
demographic. High cpw. Young
population. Low life expectancy.
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http://environmentalet.org/env1100/demoframes.htm
Japan’s fertility rate is projected to drop far
below replacement, but population will
remain high for 50 years.
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log-population
log(pop)
d log(pop) / dt
Dropping TFR
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decrease the birth rate!
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Unintended pregnancy in the US
In 1994,
49% of pregnancies were unintended
54% of these ended in abortion
48% of women have had ≥1 unplanned pregnancy
28% of women have had ≥1 unplanned birth
Highest unintended pregnancy rate among women 18-24,
unmarried, low-income, minority.
Stanley K. Henshaw. Unintended Pregnancy in the United States. Family
Planning Perspectives 30(1), January/February 1998
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1940
1960
1980
2000
Contraceptive vaccines
Besides the availability of the present methods of birth control, the population explosion
and unintended pregnancies continue to pose major public health issues worldwide. The
world population has exceeded 6.43x109 (World POPClock projection, 2005) and
increasing by 1x109 every 12 years. Ninety-five percent of this growth is in the
developing nations. In the USA, half of all pregnancies are unintended, which result in
>1x106 elective abortions annually (Henshaw, 1998; Grow and Ahmed, 2000). This calls
for a better method of contraception that is acceptable, effective and available both in the
developed and developing nations. An ideal contraceptive method should be highly
effective and safe, inexpensive, have a prolonged duration of action, be rapidly
reversible and easily accessible, require infrequent administration, and be capable of
private use (Contraception Online, 2004). A contraceptive vaccine (CV) has been
proposed as a valuable alternative that can fulfill most, if not all, of the properties of an
ideal contraceptive. Since the developed and most of the developing nations have an
infrastructure for mass immunization, the development of vaccines for contraception is
an exciting proposition.
Rajesh K.Naz1,4, Satish K.Gupta2, Jagdish C.Gupta3, Hemant K.Vyas3 and
G.P.Talwar3 Recent advances in contraceptive vaccine development: a minireview. Human Reproduction Vol.20, No.12 pp. 3271–3283, 2005
Fertility correlates with poverty
From the UN, Economic and Social Council Commission on Population and Development
3 April 2009
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Fertility Rate vs GDP
replacement rate
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CIA World Fact Book
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Education and healthcare
= lower fertility
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Total number of grant opportunities listed on Grants.gov which
include the word “overpopulation” anywhere in the full
announcement.
✴
2
✴Agencies:
http://www.grants.gov/search 21-Feb-2010
1.
2.
Bangladesh USAID-Dhaka
Pakistan USAID-Islamabad
Same search, using “overpopulation” in Nov 2012
✴
0
http://www.grants.gov/search 30-Nov-2012
Search using “Alzheimer”: 16 hits
Search using “cancer”: 131 hits
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Contraception is the greenest technology
Cost per ton of CO2 abatement
Family planning
wind
solar
clean coal
plug-in hybrids
electric vehicles
$7
$24
$51
$57 - 83
$92
$131
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a growing chorus
"global warming, the stunning rise of middle
classes all over the world, and rapid population
growth have converged in a way that could make our
planet dangerously unstable."
Thomas Friedman, NY Times columnist,
author of “Hot, Flat and Crowded”
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a growing chorus