The world is facing a global food crisis brought on by Russia’s invasion of Ukraine. Russia and Ukraine’s agricultural products are critical for global food security—Russia and Ukraine account for 13 percent and 8.5 percent of the world’s wheat exports, respectively—and sanctions against Russia, as well as Moscow’s naval blockade of Ukraine’s sea ports, have taken these vital exports off the market. As a result, millions of people are at risk of experiencing acute food insecurity, particularly in the developing world. The stakes are high: a food crisis on this scale could lead to catastrophic global hunger, fuel political instability in countries that depend on grain imports, and send shock waves throughout the global economy.

The international community has military and diplomatic options to ease this looming crisis, but all have downsides. NATO could use its formidable navies and extensive air power to escort Ukrainian grain ships. But a treaty known as the Montreux Convention limits the size of the force that can enter the Black Sea, and Russia might oppose convoys with its own naval arsenal, most likely by using mines and submarines. Alternative approaches, such as third-party convoys or shipping grain from non-Ukrainian Black Sea ports, would be less provocative but would still hinge on Russian acquiescence.

There are, in short, no easy fixes to this crisis. But difficult as the choices may be, the West cannot simply ignore the problem. Eventually, should hunger grow widespread and lead to political instability, there will be mounting pressure on the West to act. The United States and its allies must have a plan in place—even an imperfect one—if they wish to avoid a global disaster that could spiral out of control.


One way of circumventing Russia’s naval blockade and freeing up shipments of Ukraine’s agricultural exports would be to route them overland. With the help of neighboring countries such as Poland and Romania, Ukraine has already turned to roads and railways to ship grain. These methods of transport offer one major advantage: Russia lacks the ability to interdict such movement. Although rail lines are, in theory, vulnerable to attacks by missiles or aircraft, such interdiction is very hard to pull off for an extended period. As the Allies learned in World War II when they attempted to disrupt German and Japanese railways, rail lines are relatively easy to repair—one simply fills in craters and lays new tracks―so attacks must be continual. Russia lacks the means to carry out this approach: the country has depleted its arsenal of high-precision missiles necessary for such an assault, and its air force does not venture deep enough into Ukrainian territory to strike the rail lines bringing grain to European ports.

Unfortunately, Ukraine’s rail system lacks the capacity to make up for the loss of sea trade. Moving the entirety of Ukraine’s food exports—estimated at 30 million tons of grain—would require 100 shiploads, compared with a whopping 300,000 rail carloads. Some calculations suggest that it would take 14 months to move all the grain by rail but only four months by sea. Given the scale of the undertaking, a ground-shipment approach is a useful interim measure, but it is not a long-term solution to the developing food crisis.


NATO could seek to break Russia’s naval blockade by providing convoys for merchant ships headed to Ukrainian ports, which would provide the rapid flow of food that the world needs. But this strategy would face several obstacles, foremost being Russia’s significant naval forces, which would have the capacity to attack any Western ships that intervene in the conflict. Russia’s Black Sea fleet currently has five frigates, some amphibious ships, dozens of coastal-defense craft, and most important, six new Kilo-class diesel-electric submarines. These submarines, the most advanced in the Russian inventory, were constructed with sophisticated quieting measures, incorporate an advanced sonar, and are armed with torpedoes, cruise missiles, and mines. Russia also has antiship missiles based in Crimea with ranges of at least 200 miles, but its recent abandonment of Snake Island opens a lower-risk zone in the west.  

Russia’s grip on the Black Sea is not absolute: the loss of the Moskva, Russia’s flagship Black Sea missile cruiser, in April dealt a serious blow to Moscow’s ability to control Ukrainian waters. Although the Moskva had little capability against land targets and could not help with attacks on Ukrainian ground forces and infrastructure, it had 16 massive antiship missiles that would have dominated naval combat in the Black Sea had that occurred. As global attention turns toward Ukraine’s sea ports, the Russian military will feel the loss of the Moskva acutely.

NATO, however, will be limited in its ability to loosen Russia’s grip on the Black Sea because of the Montreux Convention. The 1936 agreement regulates maritime traffic in the Turkish straits linking the Black Sea to the Mediterranean. It allows unrestricted access to merchant vessels, and relatively free passage to Black Sea countries, but limits the size and number of warships that can transit the straits and the length of deployments by non–Black Sea countries. That caps the West’s ability to move forces into the area: non–Black Sea nations are each limited to a maximum weight of 30,000 tons, an aggregate total of 45,000 tons, and a stay of no more than 21 days. The convention also prohibits submarines from non–Black Sea nations, thus sidelining one of NATO’s great naval strengths. The United States is not a signatory to the Montreux Convention, so in theory these rules do not apply to the U.S. Navy. Washington has, nonetheless, complied with the agreement out of consideration for the rules-based international order and in deference to Turkey, a fellow NATO member.

Moscow’s naval blockade of Ukraine’s sea ports has taken Ukraine’s vital food exports off the market.

Ultimately, use of the straits will depend on Ankara, which could, in theory, bend the rules to facilitate a NATO naval buildup. But given Turkey’s relatively neutral stance in the conflict, its reluctance to jeopardize relationships with either Russia or the West, and its historical unwillingness to undermine the convention, the restrictions will likely hold. At most, Turkey might be willing to interpret some provisions flexibly, but such a concession would likely come at a high cost for the West, such as the provision of economic assistance, relief from some sanctions, or turning a blind eye to human rights violations.

NATO could work within the limitations set by the convention, which does permit some force buildup. The 45,000-ton restriction on vessels from external powers would allow about five destroyers. A U.S. DDG-51 class destroyer, an advanced multimission warship, would account for about 9,000 tons; a British Type 45 destroyer, which is also suited for a wide variety of tasks, would account for about 7,350 tons. Given the 30,000-ton cap on a single country’s forces, the United States could send three destroyers, and other countries such as Great Britain or France could send the other two. These five ships could provide a powerful escort for merchant ships carrying Ukrainian grain notwithstanding their limited numbers.

NATO could also bring its considerable air power to bear. Assuming that Romania and Bulgaria cooperate by providing bases and allowing NATO aircraft to fly over their territory, NATO’s airpower would dominate Russian surface forces and air forces in the Black Sea region—and help with the undersea battle.


If NATO sailed convoys to Ukrainian ports, it might have to contend with a Russian attack. Given Russian President Vladimir Putin’s repeated warnings to NATO to not intervene in the conflict, it seems unlikely that he would let a NATO convoy break Russia’s blockade without taking some kind of action. Russia would also have a strategic advantage in that it would not need to interdict all cargo movement. An attrition rate of even 25 percent would likely be more than NATO and maritime shippers would be willing to tolerate.

Russia would most likely use naval mines and submarines to attack the grain convoys, since these weapons are not only effective but also covert and deniable, which would mitigate the blame assigned for shooting first. Russia has already sown undersea mines in the approaches to Ukrainian ports. Ukraine could try to sweep them, but that would require a slow and painstaking search by small and vulnerable vessels. Further complicating the matter is the fact that Ukraine has also mined its coastline to defend against Russian forces; it would not be difficult for Moscow to point fingers at Kyiv should a mine damage a grain ship.

Russia’s grip on the Black Sea is not absolute.

The six Kilo-class submarines in Russia’s Black Sea fleet would pose the biggest threat to convoys, given that they are quiet and well armed. They could attack with torpedoes, launch cruise missiles from outside the escorts’ effective reach, or lay mines in the path of a convoy. Ground-based antiship missiles from Crimea could snipe at ships, and a major battle would likely erupt as NATO tried to suppress the Russian missile batteries. Other Russian forces would be unlikely to participate in any substantial way. Russia’s weak surface forces would not be a match for even a limited NATO escort. They could try sniping at convoy ships from close to shore, but that would expose them to Ukrainian antiship missiles and NATO airpower. Russia could also use its substantial air forces, but these are fully engaged in the ground war and have performed poorly thus far.

If Russia chose to contest the convoys, the world would likely find out when explosions rocked a grain ship. Russia would deny any involvement, claiming that the ship had hit a Ukrainian mine. NATO could accept Russian denials of involvement and try a different approach, should it wish to avoid further escalation. Alternatively, it could begin a naval campaign to clear mines and defeat Russian submarines. In that case, a naval shooting war would ensue.

Such a war would devolve into a series of convoy battles as NATO worked to push cargo vessels through the Russian blockade. There would be ample opportunity for such skirmishes given that a convoy sailing at a standard 12 knots would take about a day to sail from the port of Odessa to the straits. The outcome of such a battle would be uncertain because there is no modern precedent for a naval engagement between peer competitors. Unlike warfare in the air and on the ground, few naval engagements have occurred since the end of World War II. It is likely that NATO, with its powerful ships and its massive air power advantage, would prevail—perhaps quickly, perhaps after an extended series of convoy battles. But many NATO nations will not have the stomach for a direct military confrontation with Russia and all the risks of escalation that would inevitably bring, even if it could break Moscow’s blockade and relieve the mounting food crisis.


A less confrontational option would be to enlist non-NATO countries to provide escorts and cargo ships. A country like Egypt, which depends heavily on imported grain, might be willing to take on the risks a convoy would entail. This indirect approach would avoid a Russian narrative of NATO aggression and lean heavily on the humanitarian argument of relieving hunger. Ultimately, however, this is a diplomatic calculation because these third-party countries likely do not have the military capability to fight Russia effectively.

Ukraine could transport grain by rail to the Romanian port of Costanta, which is only 190 miles from Odessa, and from there, ship it by sea using third-party vessels. This would avoid any direct connection with Ukraine and the war, thus allowing Russia some distance if it wanted to avoid a confrontation. Russia might not be willing to let such a scheme slide, however, in the face of sanctions against its own exports.

Difficult as the choices may be, the West cannot simply ignore the problem.

The United States could take a direct approach by registering, or reflagging, merchant vessels as American ships, so that Russia would have to attack U.S. vessels to enforce the blockade. There is a precedent for such a move: the United States reflagged Kuwaiti oil tankers to provide U.S. naval protection during the Iran-Iraq War in 1987–88 to ensure the continued flow of oil. This is a risky strategy, though; even during the tanker war, these reflagged tankers were subject to sniping and mining, and they needed escorts as a result, regardless of their redesignated nationality. Russia likewise might not be deterred by this tactic.

There are also diplomatic options that could be worth pursuing. Putin, for instance, has stated that Russia would allow shipments from Ukraine under some conditions. One could imagine a ship-for-ship agreement, in which one merchant ship from Ukraine would be allowed to engage in international trade in exchange for one ship from Russia doing so. This tit-for-tat proposal has gained little traction, given that it would provide Russia substantial financial resources and constitute a precedent for lifting sanctions. Still, Western nations have been reluctant to risk military confrontation, and the global food situation will grow increasingly dire. A diplomatic approach might win international support over time.

Countries depending on Ukrainian and Russian grain likely have enough supplies to last for a while, and their stores are being boosted by Western aid in the short term. There are no current reports of hunger. But over the longer term, the status quo will prove untenable. Should the war continue, dwindling supplies will cause shortages and food riots that could lead to social and regime instability. The West will face mounting pressure to act. Global hunger may not be acute yet, but when it hits, it will hit hard. It is the responsibility of NATO and the West to have a plan in place before the shortage becomes a crisis.

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  • MARK CANCIAN is Senior Adviser at the Center for Strategic and International Studies’ International Security Program.
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