A tentative proposal to tax cryptocurrency mining to raise funds for climate action took off during a United Nations climate conference that’s set to come to a close today.A levy on energy-hungry crypto mining, at $0.045 per kilowatt-hour (kWh) of electricity used, could generate $5.2 billion in revenue annually, according to a report released last week by the Global Solidarity Levies Task Force, led by Kenya, Barbados, and France.The Bitcoin network is estimated to use more electricity annually...