diff --git a/fsspec/config.py b/fsspec/config.py
index 76d9af14a..19f68071c 100644
--- a/fsspec/config.py
+++ b/fsspec/config.py
@@ -30,18 +30,18 @@ def set_conf_env(conf_dict, envdict=os.environ):
     envdict : dict-like(str, str)
         Source for the values - usually the real environment
     """
+    envdict = dict(envdict)
     kwarg_keys = []
     for key in envdict:
         if key.startswith("FSSPEC_") and len(key) > 7 and key[7] != "_":
+            try:
+                value = json.loads(envdict[key])
+                envdict[key] = value
+            except json.decoder.JSONDecodeError:
+                value = envdict[key]
             if key.count("_") > 1:
                 kwarg_keys.append(key)
                 continue
-            try:
-                value = json.loads(envdict[key])
-            except json.decoder.JSONDecodeError as ex:
-                warnings.warn(
-                    f"Ignoring environment variable {key} due to a parse failure: {ex}"
-                )
             else:
                 if isinstance(value, dict):
                     _, proto = key.split("_", 1)
diff --git a/fsspec/tests/test_config.py b/fsspec/tests/test_config.py
index dc251a0d9..84d3e7b09 100644
--- a/fsspec/tests/test_config.py
+++ b/fsspec/tests/test_config.py
@@ -30,7 +30,7 @@ def test_from_env_ignored(clean_conf):
         assert "unexpected name" in str(w[0].message)
         assert "unexpected name" in str(w[1].message)
         assert "unexpected name" in str(w[2].message)
-        assert "parse failure" in str(w[3].message)
+        assert "not being a dict" in str(w[3].message)
         assert "not being a dict" in str(w[4].message)
     assert cd == {}
 
@@ -45,7 +45,7 @@ def test_from_env_kwargs(clean_conf):
     with catch_warnings(record=True) as w:
         set_conf_env(conf_dict=cd, envdict=env)
         assert len(w) == 1
-        assert "parse failure" in str(w[0].message)
+        assert "not being a dict" in str(w[0].message)
     assert cd == {"proto": {"key": "value", "long_key": "othervalue"}}
 
 
@@ -62,15 +62,13 @@ def test_from_env_protocol_dict(clean_conf):
 
 def test_from_env_kwargs_override_protocol_dict(clean_conf):
     env = {
-        "FSSPEC_PROTO_LONG_KEY": "override1",
+        "FSSPEC_PROTO_LONG_KEY": "1",
         "FSSPEC_PROTO": '{"key": "value1", "long_key": "value2", "otherkey": "value3"}',
         "FSSPEC_PROTO_KEY": "override2",
     }
     cd = {}
     set_conf_env(conf_dict=cd, envdict=env)
-    assert cd == {
-        "proto": {"key": "override2", "long_key": "override1", "otherkey": "value3"}
-    }
+    assert cd == {"proto": {"key": "override2", "long_key": 1, "otherkey": "value3"}}
 
 
 def test_from_file_ini(clean_conf, tmpdir):