diff --git a/tests/core/env/test.sh b/tests/core/env/test.sh
index ed910f94a3..28a038b32d 100755
--- a/tests/core/env/test.sh
+++ b/tests/core/env/test.sh
@@ -12,7 +12,7 @@ rlJournalStart
         rlRun -s "TMT_DEBUG=3 tmt plan show"
         rlAssertGrep "Using the 'DiscoverFmf' plugin" $rlRun_LOG
         rlRun -s "TMT_DEBUG=weird tmt plan show" 2
-        rlAssertGrep "Invalid debug level" $rlRun_LOG
+        rlAssertGrep "Invalid value.*'weird' is not a valid integer" $rlRun_LOG -E
     rlPhaseEnd
 
     for execute in 'tmt'; do
diff --git a/tmt/log.py b/tmt/log.py
index 753e8e3902..1de96e78ed 100644
--- a/tmt/log.py
+++ b/tmt/log.py
@@ -108,21 +108,6 @@ def create_decolorizer(apply_colors: bool) -> Callable[[str], str]:
     return tmt.utils.remove_color
 
 
-def _debug_level_from_global_envvar() -> int:
-    import tmt.utils
-
-    raw_value = os.getenv('TMT_DEBUG', None)
-
-    if raw_value is None:
-        return 0
-
-    try:
-        return int(raw_value)
-
-    except ValueError:
-        raise tmt.utils.GeneralError(f"Invalid debug level '{raw_value}', use an integer.")
-
-
 def decide_colorization(no_color: bool, force_color: bool) -> tuple[bool, bool]:
     """
     Decide whether the output and logging should be colorized.
@@ -626,19 +611,13 @@ def apply_verbosity_options(
         else:
             self.verbosity_level = verbosity_level
 
-        debug_level_from_global_envvar = _debug_level_from_global_envvar()
+        debug_level_from_option = cast(Optional[int], actual_kwargs.get('debug', None))
 
-        if debug_level_from_global_envvar not in (None, 0):
-            self.debug_level = debug_level_from_global_envvar
+        if debug_level_from_option is None or debug_level_from_option == 0:
+            pass
 
         else:
-            debug_level_from_option = cast(Optional[int], actual_kwargs.get('debug', None))
-
-            if debug_level_from_option is None or debug_level_from_option == 0:
-                pass
-
-            else:
-                self.debug_level = debug_level_from_option
+            self.debug_level = debug_level_from_option
 
         quietness_level = actual_kwargs.get('quiet', False)
 
@@ -868,7 +847,14 @@ def get_bootstrap_logger(cls) -> 'Logger':
             # Stay away of our future main logger
             actual_logger = Logger._normalize_logger(logging.getLogger('_tmt_bootstrap'))
 
-            cls._bootstrap_logger = Logger.create(actual_logger=actual_logger)
+            # The environment variables are usually handled at the click cli stage
+            # Here we enable safe parsing of those variables.
+            try:
+                debug = int(os.getenv('TMT_DEBUG', 0))
+            except ValueError:
+                debug = None
+
+            cls._bootstrap_logger = Logger.create(actual_logger=actual_logger, debug=debug)
             cls._bootstrap_logger.add_console_handler()
 
         return cls._bootstrap_logger
diff --git a/tmt/options.py b/tmt/options.py
index 04f5569804..b755398510 100644
--- a/tmt/options.py
+++ b/tmt/options.py
@@ -132,7 +132,7 @@ def option(
         '-v', '--verbose', count=True, default=0,
         help='Show more details. Use multiple times to raise verbosity.'),
     option(
-        '-d', '--debug', count=True, default=0,
+        '-d', '--debug', count=True, default=0, envvar="TMT_DEBUG",
         help='Provide debugging information. Repeat to see more details.'),
     option(
         '-q', '--quiet', is_flag=True,