Brent crude is trading above $100 a barrel again.

That's bad news for anyone filling a gas tank, and the knock-on effects of rising oil prices are obvious.

But I also recommend paying close attention to what happens when oil prices fall.

Earlier this month, Brent surged above $107 as attacks on Saudi infrastructure and shipping intensified.

It then suffered a five-day losing streak as Saudi oil flows improved and hopes for U.S.-Iran diplomacy grew.

Yesterday, Brent even closed below $100 for the first time in weeks. But it’s already bounced back above $102.

That’s a long way from the $60–$70 levels we saw before the war.

So what if the floor under oil prices is moving higher?

The Damage Is Getting Harder to Undo

Energy infrastructure has never been completely off-limits in this war.

In March, Israeli strikes hit Iran's South Pars gas field and the Asaluyeh processing hub.

Iran responded by attacking energy facilities across the Gulf, including Qatar's massive Ras Laffan LNG complex.

The strikes knocked out about 17% of Qatar's LNG export capacity, with repairs expected to take years.

But there were also striking examples of restraint.

When U.S. forces attacked Kharg Island in March, Trump said the military destroyed military targets while leaving its oil infrastructure intact. Kharg handles most of Iran's oil exports.

Iran, meanwhile, repeatedly showed that its missiles and drones could hit difficult targets across the region.

In other words, both sides appeared capable of inflicting far greater damage on the energy system than they initially chose to inflict.

Then that pattern began to change.

Commercial ships increasingly became targets this summer as attacks around the Strait of Hormuz intensified.

By early September, the U.S. said it had attacked 10 Iranian oil tankers in one week. Iran responded by attacking 10 ships near Hormuz

Then the damage spread beyond ships.

On Sept. 11, drone attacks damaged three pumping stations along Saudi Arabia's East-West Pipeline — one of the country's main ways to bypass Hormuz.

The pipeline can move roughly 4 million barrels per day from Saudi Arabia's eastern oil fields to the Red Sea.

It restarted this week, helping push Brent lower. But the pipeline is operating at reduced rates, and restoring full capacity could take weeks.

Months of fighting have now damaged pipelines, pumping stations, processing facilities, and oil tankers.

And unlike a geopolitical “risk premium,” that damage doesn't disappear when the missiles stop flying.

An attack can take minutes. Repairs can take months.

The disruption is already making oil more expensive to move

This week, Iraq's oil minister said the cost of shipping its crude has jumped from $26 to $37 per barrel.

The world doesn't need to “run out of oil” for prices to remain elevated.

If there are fewer safe routes, fewer ships, less refining capacity, and damaged pipelines, delivering the same barrel costs more.

And those problems don't disappear when the shooting stops.

We're getting a real-time test of this idea right now.

What Happens to the Floor?

Compare today's oil prices with where they traded before.

Before the conflict this spring, Brent spent much of the winter around $60–$70. It returned to the low $70s during this summer's calm.

I'm not trying to declare that $80, $90 or $100 is oil's new permanent floor.

The behavior matters more than the number.

If each new flare-up sends Brent higher, and each period of calm leaves it higher than before, the market may be telling us that something important has changed.

And the damage isn't limited to the Middle East.

Ukraine continues attacking Russian refineries, while Russia continues striking Ukraine's energy system.

Two Russian refineries were forced offline this month following Ukrainian drone attacks.

At one, damage to its main crude-processing unit was expected to take at least a month to repair. Another major refinery near Moscow was hit over the weekend.

The two wars aren't directly related. But their effects on global energy markets can add up.

Every refinery knocked offline reduces the system's ability to turn crude into usable fuel.

And with infrastructure being damaged in two critical energy-producing regions at once, the world's cushion for absorbing the next disruption gets thinner.

We've seen what can happen when an energy shock hits an economy already dealing with other problems.

In 2007 and 2008, the U.S. housing market was weakening and financial conditions were tightening.

Meanwhile, Brent surged from around $50-$60 a barrel in early 2007 to nearly $150 in 2008.

Oil didn't cause the financial crisis. But soaring energy costs added another burden at exactly the wrong time.

Today's economy is very different. Still, persistently high oil would put more pressure on household budgets and corporate margins while making inflation harder to contain.

We're already seeing stress in diesel markets, where refining margins have surged to record levels amid global supply shortages.

And that could make the Federal Reserve's job much harder.

The Real Test Comes With Calm

There is some encouraging news in all of this.

At the United Nations this week, the U.S. and Iran held their first indirect talks in months. Iran has also discussed reopening Hormuz as part of a broader agreement.

Maybe diplomacy works. Maybe Hormuz reopens. Maybe Brent falls sharply.

But even if the war ended tomorrow, the world's energy system wouldn't magically reset to where it was before the fighting began.

Pipelines still need repairs. Refineries need rebuilding. Ships need replacing.

That's why I'm no longer watching to see how high Brent goes during the next attack.

I'm watching to see how low it goes during the next period of calm.

If Brent keeps settling at higher levels, we'll have growing evidence that this isn't simply another temporary oil spike.

It could be the beginning of a new price regime.

And with the consequences stretching from the gas pump to inflation, interest rates, and ultimately the stock market, I'll be watching that floor very closely.