Is Air Travel Really Bad For the Climate?

"The best way to get oneself somewhere with the least impact on the climate is a lot more complex than it may seem at first glance," writes Slashdot reader Dan Drollette (who is also the deputy editor of The Bulletin of the Atomic Scientists).

Slashdot reader Lasrick also submitted their report. A few excerpts:
- For a short distance taking a train may be better than flying, but there is some ambiguity for long-distance travel. But no matter what mode of travel we choose, the distance traveled strongly determines emissions.

- Trends suggest that ground transportation is increasingly being electrified (with the potential for using renewable sources). However, there is likely no such technological breakthrough on the horizon for planes. Thus, flying less is an important long-term commitment because it helps to make sure there are more alternative transportation options, and shows where we want government and industry to prioritize efforts toward efficiency and transit... [I]f you choose to drive because it is more climate-friendly than flying short-haul, you are adding an extra car on the road while the plane would have flown anyway. However, in the long run, if many people choose to drive (hopefully in a full car), it is likely there will be fewer short-haul flights.

Obviously, fewer passengers per vehicle will also increase the per-passenger carbon count, and right now short economy flights "generally have higher occupancy and lighter fuel loads," placing them just below a U.S. grid-powered electric car. And mode of transportation is still less important than distance traveled, though very short flights less than 1000 kilometres (621 miles) are more carbon intensive than longer flights "as they spend little time cruising, and are often not very direct."

Energy sources also matter, since trains in Europe are largely electrified, while North America's trains burn fossil fuels. "In Europe, trains are by far the best choice in terms of climate benefits, even if that's not as true elsewhere." Thus the three worst choices right now are a large car (getting 15 miles per gallon), followed by a long (non-economy) business flight, and a "medium" car (getting 25 miles per gallon), while the three best choices are a solar-powered electric car (#3), a crowded U.S. school bus, and Eurostar rail.

But it's important to remember that the majority of people don't fly, Dan Drollette reminds us, "And we should not be so focused on the carbon contributions of air travel (which only account for 2 percent of all carbon emissions) that we take our eyes off the causes of the other 98 percent of carbon emissions."