Time trends and persistence in the Arctic temperature

Abstract Time trends are examined in Arctic temperatures by using a fractionally integrated model. The results indicate that globally, the time trend coefficient is significantly positive and the degree of differentiation is equal to 0.32. Looking at subsamples of 25 years, the time trend is only found to be significantly positive in the last two subsamples, being particularly high in the final one corresponding to data starting at January 2001. For this period, the degree of integration is also the highest across all subsamples. This result supports the hypothesis that temperatures in the Arctic region have increased in recent years.