Dive Brief:

• Allbirds co-founders Joey Zwillinger and Tim Brown called Amazon out for allegedly knocking off the brand's Wool Runner, but not its sustainable practices, in a Medium post Monday. Amazon did not immediately respond to Retail Dive's request for comment. 

• "We are flattered at the similarities that your private label shoe shares with ours, but hoped the commonalities would include these environmentally-friendly materials as well," the post reads. The co-founders highlighted the fact that they've shared their renewable materials with "over 100 other brands."

• The DTC shoe brand also used the opportunity to emphasize the impact sustainable manufacturing can have on fighting climate change, noting that the foam Allbirds uses for its shoes removes carbon from the atmosphere in the process. "You can use it. We want you to use it," the founders wrote, ending the letter with a somewhat cheeky call to action: "Please steal our approach to sustainability."

Dive Insight:

Amazon is a polarizing entity for brands. That was reinforced earlier in November, when Nike announced it would no longer sell through the company and would focus instead on "more direct, personal relationships." The announcement ended a two-year agreement between the shoe brand and the e-commerce giant. 

Brands choosing whether or not to sell on the platform are forced to grapple with its counterfeit issues, which have twice caused the American Apparel & Footwear Association to recommend it to the U.S. trade office as a notorious market, as well as the underlying fear that Amazon may study a brand's best-performing products and create its own private label version of them.

Allbirds is used to its products being copied by other brands. While the open letter they wrote called out Amazon for this practice, the focus was on sustainability and the responsibility that businesses have to fight climate change. 

"If you replaced the oil-based products in your supply chain with this natural substitute (not just for one product, but all of them), we could jointly make a major dent in the fight against climate change," the Allbirds founders wrote. "With the help of your immense scale, the cost of this material will come down for all users of this material, allowing for even broader adoption."

Allbirds is a B Corp that was founded on a sustainable ethos, but one which also highly prised comfort and design. Since then, that same approach has been taken to extend its product line from just the Wool Runners it became known for to a broader selection of shoe designs, and even a line of socks.

Like others founded with the environment in mind, Allbirds' Zwillinger and Brown know it's increasingly a deciding factor for where consumers shop, and that the fight against climate change is also landing more and more in the hands of businesses.

"Customers value companies that are mindful of the planet and profits," the founders wrote, "and we believe the most powerful businesses in the world, such as Amazon, should lead on these issues, and will be rewarded for doing so."