Early this morning, Tesla CEO Elon Musk tweeted that it is now possible to buy a Tesla car with bitcoin, the famous cryptocurrency. Last month, the company bought around $1.5 billion of bitcoin and announced its plans to start accepting the online currency. The automaker expects about 5% of transactions to be using bitcoin, but they are hoping for this to grow as cryptocurrency use becomes more widespread. It makes sense that Tesla, a futuristic company, would accept such a futuristic currency. But for Tesla, a company that makes such environmentally friendly products, accepting bitcoin seems like a step backwards. With millions of computers mining bitcoin nonstop, the annual carbon footprint of the bitcoin mining industry is larger than all of Argentina’s. And Argentina is a country of nearly 50 million people. Tesla has prevented hundreds of millions of pounds of CO2 from being pumped into the air, but accepting bitcoin as currency goes against what Tesla is as a company.