A Tufts Agricultural Economist named Parke Wilde has nudged me to write out a few more thoughts about the carbon emissions from flying. First, some assumptions based on this web source.
Assumption #1:
Los Angeles is 2400 miles from New York City and it costs 10 cents per seat mile on a plane with 120 seats to make this flight. So, the total operating cost is: $30,000.
Assumption #2:
The airline cancels the flight if its revenue does not exceed the operating costs.
Assumption #3: First class customers (assumed to be 16 pay $1000 each) and economy class customers pay $350 each.
Assumption #4: The plane uses $2600 of fuel to make the journey. So with $3 gas that equals 866 gallons of fuel
Under these assumptions, the plane will only fly if 16*1000 + N*350 >30000 so the cutoff assuming first class is full is N =56 people.
If fewer than 56 get on, the airline will cancel the flight. I'm ignoring the airline's dynamic reputation concerns.
With 56 people on board, the average carbon footprint in tons = (866*20/2000)/56. Valuing the social damage of a ton of carbon dioxide at $35 a ton yields an average damage of $5.41 dollars each. This is not a lot of social damage for the average person on the flight and number shrinks as more people get on the flight.
If more people get on the plane, their marginal footprint is tiny. If only 1 person got on the plane, this guy would not "be marginal" because the airplane would not fly. The airline makes the decision over whether to fly the flight or not. Flights are often cancelled. Revenue must cover operating costs. I will not feel much guilt as I fly to Boston in 3 weeks.
If an airline added additional flights because an academic conference was taking place at some location then I agree that the conference caused new carbon emissions.