An integrated index of recent pan-Arctic climate change

We investigate climatic changes that have occurred in the Arctic over the period 1982-2017 through examination of ten observational cryospheric time series, and develop a new quantitative composite Arctic climate change index (ACCI). Using Factor Analysis highlights joint trends of winter temperature increases and sea ice loss, tundra shifts, and secondarily summer sea ice loss, spring snow loss, and Greenland land ice loss. An Arctic-wide atmospheric circulation index (Arctic Oscillation) was not selected as a joint contributor. Distinct Arctic change began in 1990 and the trend increases after 2005 to the end of the series. That most variables of the collection project onto a single pattern of change suggests that the Arctic is responding as a coherent system over the previous three decades. However, no single index exclusively tracks change in the Arctic, a conclusion that emerges from a multivariate analysis. A composite quantitative index (ACCI) is useful to document the covariability of systematic Arctic change.