A cryptocurrency built to look cleaner than bitcoin is facing a harder environmental accounting
Chia has long presented itself as a greener alternative to bitcoin by replacing proof-of-work mining with a proof-of-space-and-time model. Instead of relying on vast quantities of nonstop computation, the system uses storage capacity, rewarding users that devote empty disk space and keep it available over time. That pitch helped distinguish Chia from the heavy electricity demands that have made bitcoin a regular target in debates over energy use and emissions.
New research summarized by New Scientist now argues that the environmental advantage has been overstated by a wide margin. The reporting says Chia's annual carbon footprint likely falls between 0.584 and 1.402 million tonnes per year, with the average estimate putting emissions at roughly 18 times the company's claimed 50,000 tonnes.
The key issue is not just electricity at runtime
The study, led by Soraya Djerrab at the Higher School of Computer Science and Digital Technologies in Algeria, examined the full process involved in using Chia. That matters because the blockchain depends on two separate activities: plotting and farming. Plotting creates the data that is later stored, while farming involves keeping that data available and proving to the network that it still exists.
Those steps do not stress hardware in the same way. Plotting is memory- and processor-intensive, and it often relies on fast solid-state drives. Farming is comparatively lighter and can be done on slower hard disks. According to the researchers, the environmental story changes significantly once the hardware burden of plotting is properly counted.
The study found that plotting wears out substantial numbers of SSDs. That means the system's footprint is not only about the electricity used while drives are active. It is also about the embodied carbon tied to manufacturing replacement hardware. In other words, the environmental cost is partly baked into the devices Chia consumes along the way.
