diff --git a/source/world_builder/utilities.cc b/source/world_builder/utilities.cc
index d0b51a685..c79e39638 100644
--- a/source/world_builder/utilities.cc
+++ b/source/world_builder/utilities.cc
@@ -1491,7 +1491,6 @@ namespace WorldBuilder
       const double ridge_drift_distance = abs(ridge_velocity) * time_of_ridge_migration; // m
 
       double effective_age_shift = 0;
-      double trench_age_shift = 0;
       if (subducting_velocity <= 0)
         subducting_velocity = spreading_velocity;