What is the carbon footprint of blockchain technology?

Believe it or not, cryptocurrency mining consumes a huge amount of electricity and pollutes the environment. The majority of Bitcoin mining capacity is located in China.

Unfortunately, the lion's share of this country's electricity is produced by burning coal, which subsequently results in one of the largest carbon emissions in the world.

There are three reasons why working with Bitcoin is extremely energy-intensive. Bitcoin initially has no value, the cost and speed of transactions also leave much to be desired. It has become an investment asset, like an expensive painting at auction. Proof of Work (PoW) is an outdated method for solving the Byzantine Generals Problem (BFT). To solve this problem, a huge amount of energy is required. In other words, the problem with Bitcoin is that the more it is mined, the more electricity it costs. The process of mining some cryptocurrencies also occurs using alternative energy sources and does not leave a carbon footprint.

Ethereum also used proof of work until recently, however, very soon the company should switch to another method - namely proof of stake (PoS). Electricity consumption for Ethereum mining will drop several times.

NEO and Hyperledger currently require the least amount of energy. NEO uses delegated Byzantine Fault Tolerance (dBFT), which is an improved version of proof of stake. Its essence is that miners with a large amount of cryptocurrency can generate their own blocks. This method reduces energy costs and significantly speeds up transactions.

Hyperledger creates tokens on a separate platform, however, the tokens must be verified by multiple participants in the system before they can be used. 

You can be sure that all the panic around Bitcoin's energy consumption will subside in a couple of months. 

According to https://www.forbes.com