Rebuilding natural landscapes such as forests, peatlands, and wetlands along Europe’s frontiers could form difficult-to-penetrate barriers for enemy armored forces, according to researchers. These nature-based defenses would cost far less than traditional concrete anti-tank structures while also delivering ecological gains. In coastal tropical regions, restoring mangrove ecosystems could provide a comparable protective function.
The concept, described as “defensive rewilding,” merges security strategy with climate resilience by placing restoration projects in locations that can slow, redirect, or obstruct invading troops. Researchers Sam Jelliman, Brian Schmidt, and Alan Chandler outlined this approach in an article published in the RUSI Journal on April 7, noting that it also supports carbon capture and biodiversity.
Unlike temporary measures such as minefields or field fortifications, rewilding produces enduring, large-scale landscape barriers that can shape military operations before combat even begins. Historical cases—from World War II to more recent conflicts like Russia’s invasion of Ukraine—demonstrate how terrain can significantly hinder offensive advances.
Although the idea is gaining interest among environmental advocates, it still awaits broader endorsement from military institutions. Jelliman, affiliated with the Sustainability Research Institute at the University of East London, said discussions are underway with defense officials, including the U.K. Ministry of Defence, to demonstrate that the approach can deliver both strategic and environmental advantages. He added that support tends to increase in countries geographically closer to Russia.
By altering terrain in potential conflict zones, defensive rewilding can make areas inaccessible to mechanized units or funnel them into vulnerable positions, thereby increasing the cost of aggression. At the same time, these natural defenses are less likely to be perceived as provocative, offering a way to strengthen security without escalating arms competition.
Cost comparisons highlight its appeal: establishing a kilometer of wetland buffer could range from about £90,000 to £540,000, significantly lower than the £1 million to £3 million required for a similar length of concrete anti-tank ditch. Restored wetlands create soft, unstable ground that may not support heavy armored vehicles, while deeper water can disrupt supply movements. Peatlands, in particular, are even less stable, making them impassable even for lighter armored units.
Historical terrain features support this idea. The Pripet Marshes, spanning Belarus and Ukraine, posed a major obstacle to German forces in 1941. Restoring such natural hydrology along modern borders could serve as a durable, self-sustaining alternative to engineered defenses.
Large areas of Eastern Europe were historically wetter but have been drained for agriculture, especially during the Soviet era. As a result, regions like northern Ukraine are now drier and easier to traverse. Re-saturating peatlands can be relatively straightforward—blocking drainage channels allows water levels to recover within a year, making the ground soft and difficult to cross again.
Peatlands are particularly valuable because they combine defensive difficulty with strong carbon storage potential. Dense forests also offer tactical advantages: they can slow tanks, interfere with drone operations, reduce the effectiveness of projectiles, and obstruct targeting systems, thereby improving defensive survivability compared to open terrain.
The Battle of Hürtgen Forest in 1944 is a notable example where dense woodland reduced the effectiveness of a technologically superior force. Similarly, in coastal regions, restored mangroves can block amphibious landings by trapping vessels and limiting access points, while also protecting shorelines from storms and supporting biodiversity.
Additional coastal defenses could include artificial reefs, which have historically hindered landing operations and also contribute to marine ecosystems and carbon capture. Inland, restoring rivers to their natural courses and softening their banks can make them far more difficult to bridge. Ukrainian forces demonstrated this in 2022 by using the terrain around the Siverskyi Donets River to disrupt repeated crossing attempts.
Future research is expected to focus on proving the practicality and effectiveness of defensive rewilding. Countries such as Finland, Estonia, and Poland are already exploring its potential. For defense ministries under pressure to reduce carbon emissions, the approach offers a dual benefit—strengthening national security while contributing to climate goals.
Restoring peatlands, in particular, is considered one of the most effective long-term methods of carbon storage. If carried out in strategically important areas, such efforts could simultaneously enhance defense capabilities and support net-zero targets. With defense budgets set to rise in the coming years, integrating environmental restoration into security planning may provide a cost-effective way to build more resilient borders.
