MODULE 4: Future People

 AGENDA

1. No office hours today
2. Duties to future people -- John Broome, William McAskill
3. Later: Peter Singer, how do divide up duty to mitigate among nations

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John Broome, "Climate Change Ethics" (Scientific American, 2008)

What sacrifices should we make--less plane travel, turning down the heat, eating less meat -- if we are sacrificing for the sake of

• people now
• people in 2050
• people in 2100
• people in 2200

How much should we spend on climate change -- mitigating, adapting, etc. -- if the benefit is received by

• people now
• people in 2050
• people in 2100
• people in 2200

Discounting view--the further out the beneficiaries, the less we have to sacrifice

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Warm up exercise

• You would pay $100 for a nice sweater.  
• What would you pay now for a sweater that will be delivered in 1 year, 2 years, 3 years, etc?
• if you would pay a discounted price, why?

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How much should we discount when it comes to climate change spending?

Suppose...

flooding from sea level rise is expected in 100 years...

we want to build a dike protecting Houston...

the dike will prevent $1 trillion in damages...

what should we spend today for the dike?

1. We should spend up to a $1 trillion today for the dike (no discount)
2. We should spend less than $1 trillion (discount).

Broome: economists say we should discount, but disagree about the discount rate

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Reasons FOR discounting

1. Alternative investment opportunities
2. Future people will be richer than us (everyone assumes)
3. The same goods will be worth less to them (diminishing marginal value)
4. Prioritarianism--we should give priority to the worse off (that's us!) not the better off (future people)
5. Pure temporal distance--events in the future just matter less, period
6. WHAT ELSE?

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Reasons against discounting, or at least for a lower discount rate

1. Utilitarianism--we should maximize total happiness, whether extra units of wellbeing are given to the worse off or the better off.
2. Temporal impartiality -- future counts just as much

Other reasons against discounting (not discussed by Broome)

1. Our old friend PCBB -- principle of commensurate benefits and burdens -- our consumption causes the future problems, so we should clean it up
2. Mitigation projects --"now or never"

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Broome's main points: 

• economists need ethics to resolve the issue of the discount rate
• his own view: lower discount rate, based on utilitarianism and temporal impartiality