Climate Change and Mobility

We live in an era where a middle-class Westerner expects to be mobile, both on a daily basis and for longer trips that come up. We expect to be able to attend weddings and funerals of relatives in distant cities, for instance, which would not have been the case a hundred years ago. Many of us have jobs that require traveling outside our home regions at least a few times a year. There are conferences and trade shows that maintain networks of researchers, activists, and businesses.

But we also know that transportation has become the largest category of greenhouse gas (GHG) emissions, and — I believe — we cannot continue with this kind of business as usual.

What amount of travel, through what means, is sustainable? I have wished to know that answer, and this may be it:


(Click to enlarge.)

Basically, this chart shows how much travel each of us can do within the 2°C limit over the next 35 years, about one ton of greenhouse gas per person per year. Westerners currently travel 12,500 miles per year on average, so that's marked with a vertical dotted line, and you can see how each form of transportation uses its GHG allocation to meet that average, or not. Or, sometimes, to exceed it.

Airplanes can all be found in the red dots down at the bottom left of the chart. (First class is twice as bad as coach, too: a first-class trip uses your annual carbon budget in three hours. Private jets are the absolute worst.) Gas-fueled cars are not a whole lot better, though it depends on how many people they carry. Trains, perhaps surprisingly, at least in the U.S. and Canada, are not much better than cars.

The hopeful action is in electric vehicles (whose carbon use varies a lot, depending on the source of the electricity) and intercity buses, which are the most efficient way to move people in North America.

This is definitely a bunch of useful information to remember and refer to.

Full discussion can be found in the National Observer's essential infographics for the climate-conscious traveler. 

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The implications of this graph for each of us personally (if we have the means to be travelling at or over the average) are explored in a recent Vox post by Dave Roberts called Reckoning with climate change will demand ugly tradeoffs from environmentalists — and everyone else. From not flying to realizing existing nuclear power plants need to be kept in the mix to adding obtrusive infrastructure to create a modern electric grid, we all have to be willing to let go of NIMBYism because climate change is an emergency.