ALGO is a carbon-negative PoS chain. It has smart contracts that monitor emissions and buys offsets from ClimateTrade.

ALGO is a PoS chain which may seem like good enough, right? Still, nodes use electricity so they implemented a mechanism to automatically offset their emissions. How cool is that!

We announced recently on Earth Day that we're the first carbon-negative chain. We have smart contracts that look at how much carbon is being consumed by the actual nodes supporting the network and make sure that offsets are automatically purchased in response to that. And that's thanks to partners like ClimateTrade that are using the blockchain for novel applications. They have only UN-approved sources of certified climate credits, and the fact that they're transacting those in a blockchain-based marketplace is really exciting.

Another good example is PlanetWatch, which is deploying air quality sensors around the world to make it both the case that people can understand what air quality looks like near them but also in cases where countries need to adhere to air quality standards or pay carbon taxes. In the cases that they're not [adhering to those standards], now they can be held accountable and there’s transparent data associated with that.

Full article here: https://www.forbes.com/sites/stevenehrlich/2021/07/12/algorand-founder-silvio-micali-breaks-down-how-to-construct-a-fast-and-secure-blockchain-in-a-world-full-of-adversaries/?sh=69253ef43fa3