(CNN) - A new report found that making purchases online and having them delivered is not good for the environment.
The main reason is the way people shop. They purchase frequently, but many people only buy a few items at a time.
This produces more packaging waste, and online items tend to come from multiple distribution centers.
For the year-and-a-half long study, researchers compared carbon footprints for products purchased at physical stores, products purchased by ordering online but going to the store for pickup, and strictly online orders that were shipped.
For more than 75% of all purchases, the carbon footprint was lower for purchases from physical stores than for items ordered online and delivered.
Most of the time – 63% – the lowest carbon footprint was for items purchased online but picked up at a brick-and-mortar store.
The report was published Tuesday in Environmental Science & Technology, a peer-reviewed scientific journal published by the American Chemical Society.