Cryptocurrency is not an obvious candidate to cut greenhouse gas emissions. Just mining bitcoin, the primary blockchain-based cryptocurrency, emits about 22 megatons of carbon per year (the precise number is hard to pin down). But Apple's co-founder Steve Wozniak is backing a new cryptocurrency promising to do just that.

Cryptocurrencies have the potential to eventually replace cash, according to new research from financial services giant Deutsche Bank. In the "Imagine 2030" research report, Germany-headquartered Deutsche Bank said cryptocurrencies may have been "additions" rather than "substitutes" in the finance world thus far, but the next decade could change that as regulatory hurdles get past.