diff --git a/mods/ITEMS/mcl_copper/init.lua b/mods/ITEMS/mcl_copper/init.lua
index a99d03f2c..937d262e2 100644
--- a/mods/ITEMS/mcl_copper/init.lua
+++ b/mods/ITEMS/mcl_copper/init.lua
@@ -1,5 +1,7 @@
 local path = minetest.get_modpath("mcl_copper")
 
+mcl_copper = {} -- initialize global variable.
+
 dofile(path .. "/functions.lua")
 dofile(path .. "/nodes.lua")
 dofile(path .. "/items.lua")