(via TEDEd) Since 1850, global average temperatures have risen by 1 degree Celsius. That may not sound like a lot, but it is. Why? 1 degree is an average. Many places have already gotten much warmer and if average temperatures increase one more degree, the coldest nights in the Arctic might get 10 degrees warmer. So how did we get here? And what can be done? Explore the challenges of net zero emissions.