What is the Climate Shift Index®?

The Climate Shift Index (CSI) reveals how much climate change is affecting the temperature on a particular day. The index ranges from -5 to +5 with positive levels indicating temperatures that are increasingly likely due to climate change (negative scores indicating conditions that are increasingly less likely). For levels 2 or higher, the index is a multiple of how often a particular temperature will occur due to climate change. For example, a CSI level of 5 means that the temperature occurs 5 times more often compared to a world without human-caused carbon pollution. This temperature would be very difficult to encounter in a world without climate change – not necessarily impossible, just highly unlikely. (More on csi.climatecentral.org)