4/ 
According to Mr. Krugman the backing of national currencies costs

💲1.85 Trillion 
⚡61.39 terawatts
🛢17.1 billion gallons of fuel
⚠342 Billion lbs CO2
♻ &gt;25%

Bitcoin
💲3.34 Billion
⚡66.7 terawatts
⚠33.9 Billion lbs C02
♻&lt;75%