### Why this patch?
 * Keep span limits independent of environment variables while preserving caller-provided defaults.
 * Replace the excluded upstream implementation with one that returns its argument unchanged.
diff --git a/sdk/src/trace/span_limits.cc b/sdk/src/trace/span_limits.cc
new file mode 100644
--- /dev/null
+++ b/sdk/src/trace/span_limits.cc
@@ -0,0 +1,22 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#include "opentelemetry/sdk/trace/span_limits.h"
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace sdk
+{
+namespace trace
+{
+namespace span_limits_env
+{
+
+SpanLimits GetSpanLimitsFromEnv(const SpanLimits &defaults)
+{
+  return defaults;
+}
+
+}  // namespace span_limits_env
+}  // namespace trace
+}  // namespace sdk
+OPENTELEMETRY_END_NAMESPACE