LONDON(Reuters) -Global benchmark Brent crude oil is up around 20% so far in June, and set for its biggest monthly jump since 2020 as Israel-Iran tensions flare-up.

Although relatively contained, the rise has not gone unnoticed just three years after Russia's invasion of Ukraine triggered a surge in energy prices that ramped up global inflation and sparked aggressive interest rate hikes.

Here is a look at what rising oil means for world markets.

1/ HOW HIGH?

Oil prices have crept rather than surged higher with investors taking comfort from no noticeable interruption to oil flows.

Still, pay attention.

The premium of first-month Brent crude futures contract to that for delivery six months later this week rose to a six-month high as investors priced in an increased chance of disruptions to Middle East supply. It remained elevated on Friday.

Trading at around $77 a barrel, Brent crude futures are below 2022's $139 high, but nearing pain points.

"If oil goes into the $80-100 range and stays there, that jeopardizes the global economy," said ABN AMRO Solutions CIO Christophe Boucher. "We are just below that threshold."

2/ SUPPLY SHOCK?

Traders have an eye on shipping, often seen as a key energy bellwether.

About a fifth of the world's total oil consumption passes through the Hormuz Strait between Oman and Iran. Disruption here could push oil above $100, analysts say. Blocked shipping routes would compound any supply shock, as any increased output from OPEC+ may not reach the international market, said hedge fund Svelland Capital director, Nadia Martin Wiggen.

The Organization of the Petroleum Exporting Countries' most recent monthly oil market report found production by the broader OPEC+ group rose in May by 180,000 barrels per day to 41.23 million bpd, less than the 411,000-bpd hike called for by the group's increase in its May quotas.

Wiggen is watching freight rates closely.

"So far, freight rates show that China, with the world's biggest spare refining capability, hasn't started panic buying oil on supply concerns," she said.

"Once China starts to buy, freight rates will rise, and world's energy prices will follow."

3/ NO OIL, NO GROWTH

Rising oil prices raise worries because they can lift near-term inflation and hurt economic growth by squeezing consumption.

High oil prices work like a tax, say economists, especially for net energy importers, such as Japan and Europe, as oil is hard to substitute in the short term.

Lombard Odier's chief economist Samy Chaar said that sustained oil prices above $100 would shave 1% off global economic growth and boost inflation by 1%.