Tensions over Ukraine are entering a critical period, driving up prices of raw materials key to the global economy, and piling pressure on governments already struggling with surging inflation.

The US has warned that Russia could attack its neighbor as early as this week, even though Moscow has repeatedly denied it plans to invade. Markets have been on edge for weeks, and an actual conflict -- or sanctions on Russia -- could drive energy and food prices even higher, and push Europe into a major supply crisis.

Crude oil is approaching $100 a barrel and gas in Europe surged on Monday. Aluminum is heading toward a record high and palladium has risen this year, while wheat continues to gain.

The crisis “could spawn a butterfly effect, sending commodity prices spiraling higher as supply woes multiply,” analysts at Bloomberg Intelligence said in a recent report. “Sanctions could usher in shortages of food and energy, causing prices of both to soar.”

With traders and policymakers scrutinizing every move and comment in the standoff, here’s a look at the potential consequences for key raw materials.

GAS HIT
One of the biggest impacts so far has been on Europe’s gas markets. Geopolitical tensions have been amplified by already limited supplies from Russia and below-average stockpiles, with prices in the region jumping nearly fivefold in the past year.

A full-blown conflict could disrupt the massive volumes that Russia sends to Europe, about a third of which comes through Ukraine. Sanctions could hit trade and keep a new pipeline, Nord Stream 2, from bringing Russian gas to Europe. That could all have a big impact on refilling inventories in the summer, making next winter difficult as well. Prices could surge even higher, and send Europe’s economy reeling. Russia would also lose huge amounts of revenue.

Still, many think it’s unlikely gas supplies would stop, or even be cut significantly.

FOOD AND FERTILIZER AT RISK
A major casualty could be even higher food prices. Ukraine and Russia together are heavyweights in global wheat, corn and sunflower oil trade, leaving buyers from Asia to Africa and the Middle East vulnerable to more expensive bread and meat if supplies are disrupted. That would add to food-commodity costs that are already the highest in a decade.

When Russia annexed Crimea in 2014 wheat prices jumped even though shipments weren’t substantially affected. Russia and Ukraine’s share of world exports has increased since, with nations like Egypt and Turkey reliant on the Black Sea breadbasket.

So far, cargoes are still flowing freely and there’s no indication of significant disruptions. But should that happen, global markets already grappling with shrinking grain stockpiles could see further shortfalls.

Russia is also one of the world’s biggest exporters of all three major groups of fertilizers. Any cuts in supply may result in a surge in already high nutrient prices, affecting crop yields and cause further food inflation.

METALS CRUNCH
Traders are also weighing the risk of disruption to Russian exports of metals including aluminum, nickel, palladium and steel, even as analysts stress that targeting Russian producers directly with sanctions would be a major own-goal for the West. US sanctions against United Co. Rusal sparked turmoil in the aluminum market in 2018, and policymakers may not want to risk a repeat.

But should Russia get cut off from the Swift international payment system as part of any sanctions, it would slow down the flow of funds and hit exports. Any disruptions to gas flows could also exacerbate problems for metal producers in Europe who’ve been cutting output in response to high energy prices.

Even short-lived disruptions could have an outsized impact at a time when manufacturers are already facing critical shortages of metals from aluminum to zinc. The fallout could be particularly dramatic in the palladium market, where Russia accounts for about 40% of global supply.

The country is less dominant in base metals, but remains one of the world’s leading suppliers, with JPMorgan estimating that it accounts for about 4% to 6% of global refined production of copper, aluminum and nickel.

OIL SPIKE
Any disruptions to oil flows from Russia, with low spare production capacity in other countries, could easily send prices rallying. JPMorgan’s analysts have even tested the possibility of a spike to $150. Prices in London are approaching $100 a barrel. Additional sanctions on top of those already affecting Russia’s oil industry could take oil higher much more quickly.

At that price, the impact on the global economy could be debilitating. It’s a reason many don’t expect sanctions to be so severe that oil flows are significantly affected. Besides, Saudi Arabia and some others in the Middle East could potentially fill the gap.

Still, traders remain edgy. Around half of Russia’s oil and condensate exports are directed to Europe. Disruptions could wreak havoc, and force trade routes to change.