The escalating air war between Russia and Ukraine is threatening to ratchet up prices at your local supermarket.

Waves of drone and missile attacks on ports and vessels in the Black Sea region have throttled both countries' exports of wheat, corn and other key ingredients. The disruptions have pushed U.S. wheat futures to three-year highs in recent weeks, and could accelerate food inflation if the bottleneck isn't removed soon, analysts warn.

Russia and Ukraine typically account for more than one-quarter of global wheat exports, most of it shipped from the Black Sea. Now, September wheat exports from Russia are expected to drop 56% from a year ago, while in Ukraine they are forecast to fall 52%, according to SovEcon, an agricultural consulting firm.

The export cutoff is raising the specter of a new global food crisis. Countries in North Africa and the Middle East, the biggest buyers of Russian and Ukrainian grain, have been forced to find new suppliers. Compounding the problem: Drought, heat waves and an unusually strong El Niño weather pattern are also endangering harvests around the world.

"These shocks are converging," said Christopher Elliott, founder of the Institute for Global Food Security at Queen's University Belfast. "We all have to expect increased prices, if not shortages, in the not-too-distant future."

The looming grain crisis repeatedly came up at this week's United Nations General Assembly in New York, with Turkey and the European Union calling for a resumption of exports.

Both Russia and Ukraine have expressed interest in a "limited ceasefire" that would cover attacks on grain and energy facilities, Secretary of State Marco Rubio told reporters on Wednesday, following a meeting with Russia's foreign minister. Still, "that won't be easy," Rubio added. Ukraine has indicated openness to a deal resuming grain shipments as long as Russia moves to de-escalate, too. Moscow has so far been dismissive of Kyiv's ceasefire proposals. An earlier deal to allow Black Sea grain exports fell apart in 2023 after Russian President Vladimir Putin pulled out.

Meanwhile, farmers in both Russia and Ukraine are stuck with a glut of grain they can't sell. In Russia, wheat prices have fallen around 40% over the past four months because of the pileup of stored grain, according to Arkady Zlochevsky, president of the Russian Grain Union.

"The situation is catastrophic," Zlochevsky said. Russia is normally the world's biggest wheat exporter. On Wednesday, its southern Krasnodar region declared a state of emergency over farmers' inability to sell their grain, state media reported.

Oleg Vasilenko, a farmer in Russia's Voronezh region, is selling his wheat at a loss because he needs to free up storage space for other crops. Strapped for cash, he expects to cut back on fertilizer when planting wheat for next season and only repair equipment when absolutely necessary.

"I'm thinking about changing careers," said Vasilenko, who has run his own farm since 2010.

Across the border, Dmytro Krasnoshchok's farm in Ukraine's Sumy region is near the front lines, putting it at constant risk of shelling. He provides his tractor drivers with radio devices to detect incoming drones, so they can try to take cover and survive Russian attacks. He is also grappling with rock-bottom prices for his wheat and rye.

"Right now the price of wheat in Western Europe is rising almost every week, while in Ukraine there has been no price increase at all," Krasnoshchok said.

The impact of the disruptions could linger into 2027. In the fall, Russian and Ukrainian farmers plant "winter wheat," whose seeds lie dormant before emerging in the spring and which accounts for the bulk of both countries' annual wheat production.

The war has upended that process. Not only are Russia's and Ukraine's farmers struggling to pay for seeds and fertilizer, they are also facing a surge in diesel costs because of drone strikes on refineries and gas stations, as well as fighting in the Middle East.

The war isn't the only factor driving up wheat prices. Record heat and sparse rainfall in Europe this summer hurt production. Shipping disruptions in the Strait of Hormuz sent fertilizer prices higher. And the world is experiencing the strongest El Niño in decades. A weather pattern marked by warming water in the Pacific Ocean, El Niño tends to cause droughts in much of the world, threatening harvests for crops from sugar to wheat.

To be sure, wheat prices are still well below their 2022-23 levels, when Russia's invasion of Ukraine, extreme weather and the pandemic triggered a surge in food prices. That is partly because the world was well-supplied with wheat going into this year.

So far, the run-up in wheat futures hasn't translated into substantial price increases on U.S. store shelves, but that is likely to change if supplies remain tight, analysts say.

The Black Sea supply shock has echoes of the war's early days in 2022, when Russian attacks largely halted Ukrainian grain exports. But one difference is that, this time, Kyiv has the ability to hit Russia with long-range drones and missiles, and has been using them to inflict pain on the Russian economy.

Starting in early July, Ukraine's drone forces struck more than 100 Russian vessels in the Sea of Azov, a shallow body of water adjoining the Black Sea, cutting off fuel supplies to the occupied Crimean Peninsula as well as a key shipping corridor for Russian grain.

"You'll get jack s-, not foreign-currency revenue, from Black Sea grain exports, you worms," the commander of Ukraine's drone forces, Robert Brovdi, posted on social media in July. Before the war, Brovdi was a prominent Ukrainian grain trader.

Further strikes damaged Russian grain export facilities in the ports of Taman and Novorossiysk. Meanwhile, Russia hit back with attacks on the Black Sea port of Odesa and other hubs for Ukrainian grain exports.

Both sides have limited alternatives for getting their grain out. Ukraine can use river ports on the Danube or overland routes. Russia has ports on the Baltic and Caspian seas, and has sought to support farmers by offering subsidies for rail transport of grain.

But for both countries, the capacity of those alternative export routes is a fraction of what they normally ship via the Black Sea.