Oil prices have risen more than 30% over the past month to surpass $100 a barrel, as renewed fighting between the United States and Iran in the Middle East threatens global energy supplies.

The attacks in the Red Sea also add to the disruption in the Strait of Hormuz, putting two key oil shipping routes under pressure.

But it is not just oil that is becoming more expensive.

Shipping costs and the cost of refining oil into fuel are rising even faster than crude oil prices, analysts say, threatening to drive up prices for diesel, jet fuel and gas if the conflict drags on.

“The crude oil spot price alone is deceptively benign,” Vishnu Varathan, head of Asia Pacific macro strategy at Mizuho, ​​wrote in a note on Friday.

Refined fuel premiums have skyrocketed, he added, showing that the energy shock is much larger than $100 Brent would normally suggest.

Brent crude oil futures were trading around $100 a barrel early on Friday after hitting the key level on Thursday. US West Texas Intermediate futures were around $92 a barrel.

Brent crude briefly reached $126 a barrel in late April before retreating as releases of strategic oil stocks, weaker demand and a provisional truce between the United States and Iran eased supply fears. Recent events have shattered that calm.

The unrest is driving up transportation and insurance costs and making it more expensive to transport oil and fuel around the world.

Mizuho estimates that shipping costs could rise from about $10 to $12 per barrel to $15 to $20 per barrel.

The greatest pressure may not be in the crude oil itself, but in the fuels made from it.

Fuel markets are becoming even tighter

Based on current crude oil prices and refining margins, Mizuho’s Varathan estimates that diesel has an effective price of more than $180 a barrel, double the $93 at the beginning of this year.

The refining premium for diesel alone has almost tripled to more than $80 a barrel, Varathan added.

Commodity strategists at ING also flagged a tightening of diesel supplies, particularly as Russia, the world’s second-largest shipper of the fuel, reportedly considers extending its export ban on the product.

“The potential supply disruptions facing the market now are greater than at any time during the war,” the strategists wrote.

The pressure extends to natural gas.

“Globally, the key issue in the face of the latest phase of attacks is that stock levels are already incredibly low,” Ellen Fraser, an energy expert and advisory partner at consultancy Baringa, said Thursday.

Normally, Europe would be building up gas reserves before winter, but storage levels remain unusually low for this time of year, Fraser said. The United States has also depleted its strategic oil reserves.

While supplies of alternative crude oil have helped cushion the oil market, refined fuels such as gasoline, diesel and jet fuel are rising faster than crude oil, Fraser said, reflecting growing concerns that those products are becoming harder to find.

“In fact, things are getting difficult,” Fraser added.