New Delhi, July 24 -- The strategic debate in South Asia is dominated by traditional security concerns, including the India-Pakistan rivalry, China's growing presence in the region, rivalry in the Indian Ocean and the persistent threat of terrorism. But the region's biggest long-term strategic problem is playing out beyond the conventional military realm. Climate change is slowly eroding the economic, institutional and resource basis on which national security ultimately depends.

Governments are still investing heavily in military modernization and border management, but the rapid impacts of climate change are creating systemic vulnerabilities that deterrence as strategy cannot meet. This is not just an environmental issue. It's a matter...