Schwinger effect from near-extremal black holes in (A)dS space

We study the Schwinger effect in near-extremal Reissner-Nordström black holes with electric and/or magnetic charges in (anti-)de Sitter (AdS) space. The formula for the Schwinger effect takes a universal form for near-extremal black holes with the near-horizon geometry of AdS2×S2 and with the proper radii for the AdS2 space and the two-sphere S2, regardless of the asymptotically flat or (A)dS space. The asymptotic AdS boundary enhances and the dS boundary suppresses the Schwinger effect, and the small radius of AdS (dS) space reinforces the enhancement and suppression.