Conversations about bitcoin mining’s environmental affects aren’t going away, and one unknown miner is stirring the metaphorical pot.

In at least six recent blocks, a miner that has yet to be identified has embedded the same message in each block’s coinbase data that reads: “This block was mined with a carbon negative power source.” Miners often leave interesting or provocative messages in their blocks, including Foundry’s #DropGold messages and F2Pool embedding Elon Musk tweets. But touting “carbon negative” mining is more a provocative message than usual.

The carbon output messages started appearing on July 10, 2021. Here’s a list of all the blocks supposedly mined at a carbon negative facility at the time this article was published:

The idea behind a “carbon negative” operation – bitcoin mining or otherwise – is to remove more carbon dioxide from the atmosphere than an entity produces.

The carbon negative status stands in contrast to a “carbon neutral” operation, which removes an amount of carbon equal to what it produces. Reaching the “carbon negative” state is generally regarded as an ambitious goal by environmentalists. So, assuming the miner is accurately describing their carbon emissions, some bragging rights might be in order.

Exactly how this bitcoin miner is achieving a carbon negative operational status along with their cost for doing so isn’t known. But here are a few possibilities:

  • Purchase carbon-offset credits;
  • Operate carbon sequestration machinery;
  • Or simply plant trees.

The persistent focus on bitcoin mining’s carbon footprint despite representing less than 0.5% of the world’s total energy consumption makes the issue a sensitive subject for most miners. And the block messages are surely not well received by every miner.

Expecting this currently unknown miner to reveal themselves and claim any due praise for their carbon reduction operations seems reasonable. Or maybe they’ll prefer to stay anonymous and simply update the network on their carbon negative mining every few blocks indefinitely.