Atlantic and Pacific multidecadal oscillations and Northern Hemisphere temperatures

Abstract

Is the end of the warming hiatus nigh? Which recent climate changes have been forced by greenhouse gas emissions, and which have been natural fluctuations of the climate system? Steinman et al. combined observational data and a large collection of climate models to assess the Northern Hemisphere climate over the past 150 years (see the Perspective by Booth). At various points in time, the Pacific Decadal Oscillation and the Atlantic Multidecadal Oscillation have played particularly large roles in producing temperature trends. Their effects have combined to cause the apparent pause in warming at the beginning of the 21st century, known as the warming “hiatus.” This pause is projected to end in the near future as temperatures resume their upward climb. Science , this issue p. 988 ; see also p. 952