diff --git a/pcmdi_metrics/io/base.py b/pcmdi_metrics/io/base.py
index 45893b037..f44a674d7 100755
--- a/pcmdi_metrics/io/base.py
+++ b/pcmdi_metrics/io/base.py
@@ -4,7 +4,8 @@
 import logging
 import os
 import re
-from collections import Mapping, OrderedDict
+from collections import OrderedDict
+from collections.abc import Mapping
 
 import cdat_info
 import cdms2
diff --git a/pcmdi_metrics/mjo/lib/dict_merge.py b/pcmdi_metrics/mjo/lib/dict_merge.py
index fd8eb2140..7619d4268 100644
--- a/pcmdi_metrics/mjo/lib/dict_merge.py
+++ b/pcmdi_metrics/mjo/lib/dict_merge.py
@@ -16,7 +16,7 @@
 #
 # Modifed by Jiwoo Lee, 2020-06-26: Skip merging when dict is empty
 
-import collections
+from collections.abc import Mapping
 
 
 def dict_merge(dct, merge_dct):
@@ -36,7 +36,7 @@ def dict_merge(dct, merge_dct):
             if (
                 k in dct
                 and isinstance(dct[k], dict)
-                and isinstance(merge_dct[k], collections.Mapping)
+                and isinstance(merge_dct[k], Mapping)
             ):
                 dict_merge(dct[k], merge_dct[k])
             else:
diff --git a/pcmdi_metrics/variability_mode/lib/dict_merge.py b/pcmdi_metrics/variability_mode/lib/dict_merge.py
index 3ca22e7a7..c8cf599e4 100644
--- a/pcmdi_metrics/variability_mode/lib/dict_merge.py
+++ b/pcmdi_metrics/variability_mode/lib/dict_merge.py
@@ -14,7 +14,7 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
-import collections
+from collections.abc import Mapping
 
 
 def dict_merge(dct, merge_dct):
@@ -32,7 +32,7 @@ def dict_merge(dct, merge_dct):
         if (
             k in dct
             and isinstance(dct[k], dict)
-            and isinstance(merge_dct[k], collections.Mapping)
+            and isinstance(merge_dct[k], Mapping)
         ):
             dict_merge(dct[k], merge_dct[k])
         else: