Great, thanks. Here's the abstract. And for context, it's a collaboration with Ford Motor Co.

... We report and compare the greenhouse gas (GHG) emissions for a 36-item grocery basket transported along 72 unique paths from a centralized warehouse to the customer, including impacts of micro-fulfillment centers, refrigeration, vehicle automation, and last-mile transportation. Our base case is in-store shopping with last-mile transportation using an internal combustion engine (ICE) SUV (6.0 kg CO2e). The results indicate that emissions reductions could be achieved by e-commerce with micro-fulfillment centers (16-54%), customer vehicle electrification (18-42%), or grocery delivery (22-65%) compared to the base case. In-store shopping with an ICE pick-up truck has the highest emissions of all paths investigated (6.9 kg CO2e) while delivery using a sidewalk automated robot has the least (1.0 kg CO2e). Shopping frequency is an important factor for households to consider, e.g. halving shopping frequency can reduce GHG emissions by 44%. Trip chaining also offers an opportunity to reduce emissions with approximately 50% savings compared to the base case. Opportunities for grocers and households to reduce grocery supply chain carbon footprints are identified and discussed.

It's interesting that consumers driving EVs reduce the cost on the same scale as deliveries (presumably in an ICE vehicle).

They omit apples-to-apples comparisons (at least from the press release and abstract)

  * Consumer ICE vs. Delivery service ICE
  * Consumer EV vs Delivery service EV
  * Sidewalk delivery robot vs Bicycle or ebike

The last is a bit bizarre - comparing a 2-mile radius sidewalk mechanism to pickup trucks and delivery vans, but omitting the very popular 2-mile delivery method.

Right but that’s a government service and it should be totally fine for them to deliver mail below cost using taxpayer money to make up the deficit.

Like every other government service - highways, defense, etc. They’re profitable to the system, but not per se.

USPS is fueled by parcel deliveries, but also in large part by literal tons of junk mail on dead trees; spammers have paid Uncle Sam handsomely to spam every citizen's mailbox for decades, and it's the most lucrative thing USPS can do with our home mailboxes.

The postal service is a quasi government entity that has operated (not to get too deep into the politics of it) for many years at a loss. It does compete with Amazon, as well as being used by Amazon, but it's very different as a business than Amazon.

I've always wondered why I don't see passed on savings for the "amazon day" thing. It's gotta be way better for their logistics to deliver bulk orders, or pick a standardized delivery day for each neighborhood or something. Why do they only offer a single dollar of credit for choosing it?

I was zeroing out the amount purchased: The comparison is the customer picks up one item vs. Amazon delivers one item, or the customer picks up 12 or 20 things vs. Amazon delivers the same amount.

I'd still love to see data.

The problem with environmental impact is really a consequence of subsidized energy costs, including the externalization of environmental cost. If the consumer and Amazon paid the actual cost of fuel, they would make valid economic and environmental choices and we wouldn't need to figure it out like this.