The Star Tribune republished an eye-catching NY Times story this weekend about waste from online shopping. Here’s the punchline of their piece:

But measuring the effect of the cardboard economy is more difficult.

There are possible trade-offs, for example. As people shop more online, they might use their car less. And delivery services have immense incentive to find the most efficient routes, keeping their fuel costs and emissions down. For its part, Amazon said that delivering to consumers straight from huge warehouses cuts down the need to distribute to thousands of stores.

So far, though, shoppers appear to be ordering online while still driving to brick-and-mortar stores at least as much as in the past, according to Sperling and other academics.

Ardeshi Faghri, a professor of civil engineering at the University of Delaware, said the increase of various emissions — which he estimated at 20 percent from 2001 to 2011 — “could be due to a multitude of reasons, but we think that online shopping and more delivery trucks are really one of the primary reasons.”

Well, it turns out that this narrative might be a bit flawed. In David Levinson and Kevin Krizek’s concise and compelling book The End of Traffic (available on Amazon), there’s some actual information about shopping trends.

Here’s the chart, showing “the amount of time spent shopping per day“:

And here’s what the book has to day about shopping trends:

The rise of online retailing allows people to substitute delivery for fetching, and reduce the amount of shopping trips. We both remember our parents schlepping us to Sears and Montgomery Wards. These giant retailers were famous for their massive catalogs, particularly come Christmas time. Catalogs were replaced by the internet, seemingly a case of the old being dismissed by the new: Sears by Amazon. […]

Shopping trips are down by about one-third in a decade, they not comprise fewer than 9% of all trips, down from 12.5% in2000. Time spent shopping per day is also down. Other evidence for this trend comes from teh UK, where sales of vans for home deliveries are at a record high.

Granted, the Times article focuses primarily on emissions, and that conclusion might be true regardless of how much time people spend shopping. Maybe the effect of so many delivery vans isn’t actually offset by the reduction in shopper car trips, or at least that’s what the Times piece seems to suggest. Maybe people are driving around anyway? Maybe delivery van efficiency is terrible?

At any rate, retail cannibalism is nothing new, as Levinson and Krizek nostalgically point out. I sometimes envision what the city would look like if half the big box stores were replaced with online retail. What would become of all that space? All those suburban lots? How do you re-use an old Walmart?