Reversal of the ITCZ Shift During the Satellite Era

Abstract A southward shift of the Intertropical Convergence Zone (ITCZ) during the latter half of the 20th century has been primarily attributed to interhemispheric differences in anthropogenic aerosol forcing. However, in recent decades anthropogenic aerosol emissions have declined, particularly over Northern Hemisphere (NH). Here, we explore the response of the ITCZ to changes in anthropogenic forcings over the past few decades. Using a suite of climate model simulations and observations, we find evidence of a northward migration of zonal‐mean ITCZ since 1979. The decrease in anthropogenic aerosols over NH mid‐latitudes and a global increase in greenhouse gases are dominant contributors to this northward shift. We also identify a small, non‐zero contribution from large volcanic eruptions. A northward shift of the ITCZ over this period is consistent with observed hemispheric asymmetries in Earth albedo trends and adds support for model projections of a continued northward shift of the ITCZ in coming decades.