Going to Vancouver, Which Way is Worse? Flying or Driving?

The other night at our neighborhood happy hour, my friend and I got in a heated argument about traveling to Vancouver: Is flying to Vancouver versus driving worse for the environment (in terms of CO2e emissions)?

We had been discuss the merits (or lack there off) of so-called carbon offsets you can buy when you fly. My friend was trying to absolve some of his guilt for flying when I informed him that if he had to go to Vancouver, then flying was probably the lowest carbon way he could have done the travel. Although initially relieved (because he felt less guilty for flying), he said he could not believe that this could be true - we've all heard how terrible for the environment flying is, so how could flying be the lowest carbon way to travel? Argument ensued.

The Answer - Is flying to Vancouver the lowest carbon emission way to travel?

The Big Picture: From a big picture perspective, my friend is correct. Flying is bad for the environment because it enables you to travel long distances easily, burning a bunch of fuel in the process. Had flying not been so quick or convenient, he would not have taken the trip, and therefore his emissions would have been a big fat ZERO.

The Technical Answer: From a technical perspective, I am correct, with the following caveat: There was only one person traveling. Here are the numbers:

1. I used the GHG Emissions Calculation Tool for Mobile Combustion from the Greenhouse Gas Protocol Initiative (World Resources Institute (2008) GHG Protocol tool for mobile combustion. Version 2.0)
2. For flying, I used a single person, traveling 3,100 km (Vancouver return) with standard US long-haul emission factors. The answer: 0.27t CO2e
3. I think the GHG tool calculates flying emissions / per passenger. So, assuming the plane was only half full, let's double the emission / passenger, just to give flying a bit of head wind (har har) = 0.54t CO2e
4. For driving, I again used a single person, traveling 5,176 km (the road distance, Vancouver return, according to GoogleMaps). I assumed a 2005 vintage car for fuel efficiency. The answer: 1.27t CO2e

So the technical answer, if one person is traveling, then YES, flying is WAY better than driving (or should I say less-bad then driving). A single person driving to Vancouver would produce over twice as many GHGs compared to if he/she had flown.


More than One Traveling?

Note the caveat: One person traveling. The picture changes when you load more people in the car. Let's say a family of three drove to Vancouver instead of flying. If you do that, you divide the driving GHG emissions by the number of passengers:

GHG Emissions of Travel to Vancouver, return (t CO2e / person):

No. of People Traveling	By Air	By Car
1	0.55	1.26
3	0.55	0.42

So, if you are three or more, driving is "better", plus you'll probably think twice about taking the trip!


Summary

So, in summary, I was right. Flying is better than driving, if you are traveling on your own.

HOWEVER, Mitch, you are still a bad boy - because you took the trip! Flying enabled you to make a trip, that if convenient air travel had not existed, you would have not taken, and therefore you would not have generated any GHG emissions.