diff --git a/src/Core/Environment.php b/src/Core/Environment.php
index 6d5f1f34b..c8f6cb806 100644
--- a/src/Core/Environment.php
+++ b/src/Core/Environment.php
@@ -43,7 +43,12 @@ class Environment
     public static function getVariables()
     {
         // Suppress return by-ref
-        return array_merge($GLOBALS, [ 'env' => static::$env ]);
+        $vars = [ 'env' => static::$env ];
+        foreach ($GLOBALS as $varName => $varValue) {
+            $vars[$varName] = $varValue;
+        }
+
+        return $vars;
     }
 
     /**
diff --git a/tests/php/Core/EnvironmentTest.php b/tests/php/Core/EnvironmentTest.php
index 220f47b58..ccd31e83e 100644
--- a/tests/php/Core/EnvironmentTest.php
+++ b/tests/php/Core/EnvironmentTest.php
@@ -53,4 +53,17 @@ class EnvironmentTest extends SapphireTest
         Environment::setVariables($vars);
         $this->assertEquals('initial', Environment::getEnv('_ENVTEST_RESTORED'));
     }
+
+    public function testGetVariables()
+    {
+        $GLOBALS['test'] = 'global';
+        $vars = Environment::getVariables();
+        $this->assertArrayHasKey('test', $vars);
+        $this->assertEquals('global', $vars['test']);
+        $this->assertEquals('global', $GLOBALS['test']);
+
+        $vars['test'] = 'fail';
+        $this->assertEquals('fail', $vars['test']);
+        $this->assertEquals('global', $GLOBALS['test']);
+    }
 }