The main topic of “Tragedy of the
Commons” is…
Over-grazing
Over-fishing
Over-population
Over-consumption
78%
13%
5%
io
n
pt
su
m
ve
r-p
o
O
O
O
O
at
io
n
ng
az
i
ve
r-f
ve
r-g
r
4%
pu
l
1.
2.
3.
4.
is
hi
ng
• Understand the “tragedy of the commons”
and its application to environmental issues
(and other issues).
• Understand different approaches to
addressing the tragedy of the commons.
• Get a close-up look at the tragedy of the
commons in the context of fisheries.
ve
r-c
on
Goals of today’s lecture
du
“A
pp
ea
ls
to
“E
ac
tio
ut
ua
n”
lc
oe
rc
io
n”
n”
5%
ca
t io
ha
nd
“I
nv
is
ib
le
io
n
pt
at
io
n
su
m
pu
l
ve
r-c
on
O
O
ve
r-p
o
ve
r-f
O
O
ve
r-g
r
az
i
ng
is
hi
ng
”
3%
19%
13%
8%
“M
5%
56%
nt
e
22%
1. “Invisible hand”
2. “Education”
3. “Appeals to
conscience”
4. “Vigilante action”
5. “Mutual coercion”
sc
ie
.. .
71%
co
n
Over-grazing
Over-fishing
Over-population
Over-consumption
ig
i la
1.
2.
3.
4.
Hardin’s solution to the “Tragedy
of the Commons” is…
“V
The main metaphor in “Tragedy
of the Commons” is about…
Tragedy of the Commons
The commute game
• Individual incentives can sometimes lead
people to make personal choices that are
bad for the group as a whole.
• Example: The commute game. Imagine a
simple world where everybody just goes
back and forth between work and home.
• Only two options: drive or take the bus.
• Only one goal: shortest possible commute.
• If everybody takes the bus, the commute
takes 20 minutes (including 10 minutes to
walk to the bus stop and wait for the bus).
• If everybody drives, the commute takes 40
minutes because of traffic jams.
• The bus gets stuck in traffic just like every
other vehicle, so you can always get to
work 10 minutes faster by driving.
1
Which is a better social outcome,
i.e., outcome for the whole group?
The commute game
• If everybody takes the bus, the commute
takes 20 minutes (including 10 minutes to
walk to the bus stop and wait for the bus).
• If everybody drives, the commute takes 40
minutes because of traffic jams.
• The bus gets stuck in traffic just like every
other vehicle, so you can always get to
work 10 minutes faster by driving.
90%
1. Everyone takes
the bus.
2. Everyone drives.
Ev
er
yo
n
e
ta
ke
s
Ev
er
yo
n
e
th
e
dr
bu
iv
es
.
s.
10%
“Invisible Hand” Monday: How are you
going to commute to work this morning?
“Invisible Hand” Monday: How are you
going to commute to work this morning?
1. Take the bus
2. Drive my car
83%
1. Take the bus
2. Drive my car
17%
41%
ri v
e
m
y
bu
s
Ta
ke
D
59%
•
•
•
•
•
D
ri v
e
m
th
e
y
bu
s
th
e
Ta
ke
10
What if the commute takes 140 minutes (up
from 40 minutes) if everyone drives, and still
just 20 minutes if everyone rides the bus?
1. Take the bus
2. Drive my car
ca
r
0%
ca
r
0%
“Invisible hand”
“Education”
“Appeals to conscience”
“Vigilante action”
“Mutual coercion”
Objection to using the “invisible hand”?
y
m
ri v
e
D
Ta
ke
th
e
bu
s
ca
r
Sometimes individual incentives can lead
people to make personal choices that are
bad for the group as a whole.
2
“Education” Tuesday: You must not
understand, so let me explain…
53%
1. Take the bus
2. Drive my car
47%
•
•
•
•
•
“Invisible hand”
“Education”
“Appeals to conscience”
“Vigilante action”
“Mutual coercion”
Objection to using “education”?
y
(Gasp!)
D
Ta
ke
ri v
e
m
th
e
bu
s
ca
r
Sometimes problems can’t be solved by
education alone.
“Appeal to conscience”
Wednesday: Don’t be a selfish jerk!
51%
1. Take the bus
2. Drive my car
•
•
•
•
•
“Invisible hand”
“Education”
“Appeals to conscience”
“Vigilante action”
“Mutual coercion”
Objection to using “appeals to conscience”?
49%
People often act like selfish jerks.
y
D
Ta
ke
ri v
e
m
th
e
bu
s
ca
r
(Gasp!)
“Vigilante” Thursday: Ride the bus or
Big Tony will break your neck.
73%
75%
1. Thursday
2. The other days
ot
he
e
ur
sd
ay
Th
ca
r
D
ri v
e
m
y
bu
s
th
e
Ta
ke
rd
ay
s
25%
28%
Th
1. Take the bus
2. Drive my car
Which do you like better, “vigilante”
Thursday or the other days?
3
•
•
•
•
•
Vote on Proposition 1: Anyone who
drives will get a $500 fine.
“Invisible hand”
“Education”
“Appeals to conscience”
“Vigilante action”
“Mutual coercion”
1. Yes
2. No
81%
Objection to using “vigilante action”?
Do you really want Big Tony running the
show?
And what ever happened to democracy
and freedom, and stuff like that?
Mutual coercion Friday: Ride the bus
or Officer Tony will fine you $500.
•
•
•
•
•
99%
1. Take the bus
2. Drive my car
o
N
Ye
s
19%
“Invisible hand”
“Education”
“Appeals to conscience”
“Vigilante action”
“Mutual coercion”
Objection to using “mutual coercion mutually
agreed upon”?
“Freedom is the recognition of necessity.”
ri v
e
m
y
“But what about my freedom?”
D
Ta
ke
th
e
bu
s
ca
r
1%
The Tragedy of the Commons
has two parts
Example: Traffic congestion
1. It’s better for the group as a whole if
everyone makes Choice A rather than
Choice B.
2. Each person individually prefers to make
Choice B.
1. It’s better for the group as a whole if
everyone takes the bus.
2. Each person individually prefers to drive.
•
•
Under the hood is a negative externality:
when I choose B, it hurts you, and when
you choose B, it hurts me.
Negative externality: My driving creates
an external cost by creating congestion
that slows down everyone behind me.
4
Example: Common areas in dorms
or group houses
Example: Splitting the bill at a
restaurant
1. It’s better for the group as a whole if
everyone cleans up after themselves.
2. Each person individually prefers to leave
their dishes in the sink.
1. It’s better for the group as a whole if
everyone orders a moderately priced
dish instead of the filet mignon.
2. Each person individually prefers to order
the filet mignon.
•
•
Negative externality: I create external
costs by leaving dirty dishes for my
housemates.
Negative externality: I create external
costs by ordering filet mignon because I
only pay 1/n of the cost of my meal.
Example: Voting
Example: Dirty coal
1. It’s better for the group as a whole if
everyone pays some attention to politics
and votes responsibly.
2. Each person individually prefers to watch
Ugly Betty.
1. It’s better for the group as a whole if
everyone avoids coal-based energy (the
dirtiest, most carbon-intensive fuel) in
favor of natural gas, wind, solar, etc.
2. Each person individually prefers to buy
coal-based energy because it’s the
lowest cost to the individual.
• Negative externality?
Example: Overfishing
•
Negative externality: My pollution creates
external costs (smog, climate change).
Overfishing: Cod
1. It’s better for the group as a whole if
everyone limits how much they fish so
that there will be enough fish next year.
2. Each person individually prefers to
maximize their individual profits by
fishing like crazy.
•
Negative externality: When I catch fish, I
create external costs by reducing your
ability to catch fish next year.
www.fishermensvoice.com/archives/...html
5
Overfishing: Tuna
• Atlantic bluefin tuna
• Worth up to $100,000
each (for making sushi)
• Highly migratory.
Decline in population
www.bigmarinefish.com/loading_901_lb_giant.jpg
www.e2.org
Solution: Ban fishing?
Solution: Limit fishing?
• Advantage: This works!
(Whale populations have
rebounded, Marine
Protected Areas work)
• Restrict types of boats,
types of gear, etc.
• Limit annual catch (TAC:
(Total Allowable Catch)
• Disadvantage #1: This is
not economically efficient
or equitable for most
fisheries.
• Advantage #1: These can help limit overfishing
• Disadvantage #2: What
about tribal rights to fish?
• Disadvantage #2: There’s still a race for fish
that can be dangerous and inefficient.
www.greenpeace.org/raw/image_full/internation...
• Disadvantage #1: Economically inefficient.
www.makah.com
The race for fish
Solution: “Privatize the commons”?
• Fish today—while you still can—before the TAC
(Total Allowable Catch) limit is reached for the year!
• Combine a TAC (total allowable catch) limit with
private property rights over that catch.
• Example: the 2005-2006 Alaska king crab season
lasted just 4 days (250 boats caught 14m pounds)
• Individual Tradeable Quotas (ITQs) makes it
possible to “own” part of this year’s catch.
• Dangerous for workers, consumers get frozen fish
• Advantage #1: The TAC limit overfishing.
• Advantage #2: No race for fish (b/c of ITQs).
• Disadvantage #1: Biological complications.
• Disadvantage #2: Equity? (Who gets ITQs?)
• Note: This is just like carbon cap-and-trade!!!
upload.wikimedia.org/.../220px-Redkingcrab.jpg
www-rohan.sdsu.edu/.../Ocn_books.htm
6