The Iran war laid bare just how dependent the world had become on a narrow, 20-mile-wide waterway. Soon after the United States launched strikes on Iran, Tehran threatened to attack ships attempting to traverse the Strait of Hormuz, the channel that carries much of the Middle East's oil and gas exports. The threat of shortages prompted governments across Asia to impose export bans, cut import duties, and begin rationing fuel to keep supplies flowing.

Six months into the war, the doomsday scenarios—price spikes, long lines at gas stations, power outages, and grounded flights—have not fully materialized, as increased production and hefty stockpiles blunted much of the damage.

Some form of normality now appears to be returning to the Strait. On Wednesday, Iran announced a new revenue-sharing agreement covering the waterway, though a military spokesperson accused the United States of "obstructing this process."

Yet the revelation of how easily Iran was able to block—and keep blocking—one of the world's most important waterways is pushing governments to diversify their energy sources. And with the prospect of a near-term U.S.-Iran deal on life support, and Iranian control of Hormuz now looking secure for years to come, the measures that saved the global oil market in the first half of the year may not work a second time.

"Global oil and gas supply is still a major point of geopolitical leverage," says Saul Kavonic, head of energy research at MST Financial. "Notwithstanding the rise of alternative and green technologies over the past decade, the global economy is still very reliant on oil and gas."

"Hostile actors can threaten that for their geopolitical ends," he adds.

A 'big wake-up call'

Before the war, roughly a fifth of the world's oil trade passed through the Strait of Hormuz, which sits between Iran and Oman. More than 80% of that cargo was bound for Asia—primarily China, India, Japan, and South Korea.

"Before this crisis many market observers would have told you it would be impossible to block or completely close the Strait of Hormuz, because a country like Iran did not have the capabilities. They tried in the 1980s, but they did not succeed," says Carole Nakhle, CEO of Crystol Energy, an energy consultancy. She is referring to the so-called Tanker War of the 1980s, when attacks on commercial shipping during the Iran-Iraq war disrupted Gulf traffic but never closed the waterway.

The conflict, she adds, has shown "how easy and inexpensive it has become to threaten very expensive energy infrastructure," with relatively cheap drones capable of putting refineries, pipelines, ports, and other multibillion-dollar facilities at risk.

"This has been the big wake-up call for the entire global energy industry. It's a fundamental paradigm shift of the last 50 years of the energy industry," says Kavonic. "We're moving from just-in-time supply chains to just-in-case supply chains."

Importers diversify

Energy importers are starting to act. Before the war, the Middle East accounted for 90% of Japan's crude oil imports and roughly 11% of its liquefied natural gas.

"Japan found it was more vulnerable than expected, particularly when it comes to LNG—it imports 100% of its energy," says Kavonic. "In Japan, if the LNG doesn't arrive, the lights go off and the country shuts down."

Tokyo is now investing elsewhere to shore up future supplies. Japan's Inpex, for example, formed a joint venture to expand its LNG investment in Australia's Northern Territory.

"It's boomtime for Woodside and Chevron, two big LNG players who aren't too concentrated in the Middle East. The oil majors are now also rapidly ramping up their investment in LNG," Kavonic says, pointing to an opportunity for buyers to diversify their sources of gas away from the Middle East.

Exporters reroute

Exporters are diversifying as well. For oil exporters, the central lesson has been the need to invest in alternate supply routes. That includes ploughing billions into building out ports on both the western side of Saudi Arabia and the Gulf of Oman, effectively bypassing the strait entirely. Oil producers are also investing in pipelines, such as Saudi Arabia's East-West pipeline, the cross-country link to Red Sea terminals that offers a partial workaround for crude shipments.

If these investments pan out, only 10% of the world's oil will need to travel through the Strait of Hormuz, down from 20% before the war.

Gas, far more than oil, could become the key energy commodity hurt by a prolonged closure of the strait. While crude oil can be carried via pipeline—potentially from producers in the Persian Gulf to ports on the western side of the Arabian Peninsula—gas cannot, meaning there are no alternative routes to bring LNG to Asia if Hormuz is blocked.

Qatar, one of the world's leading LNG producers—its exports account for roughly a fifth of global LNG trade—is trying to keep its export routes open through diplomacy, by finding new customers, and by taking rare opportunities to move its product through Hormuz. It has also established a fast recovery timeline so it can restart production once the strait reopens.

Escaping an energy collapse

The market did not collapse as analysts had feared at the start of the conflict. In April, the head of the International Energy Agency predicted that flights in Europe might soon need to be grounded because of jet fuel shortages.

Oil prices did surge to as high as $126 per barrel, but they never reached the $150-to-$200 range some analysts had feared. And although several Asian countries imposed emergency measures to conserve fuel, a lengthy and catastrophic shortage never materialized.

"The global market is proving to be more resilient to major supply shocks than many thought," Kavonic says.

One reason was the sheer volume of oil sitting in reserve. The IEA mandates that its 32 member countries stockpile at least 90 days' worth of oil; similar mandates for gas stockpiles were imposed after Russia's invasion of Ukraine. In March, the agency coordinated the release of 400 million barrels from these emergency oil stockpiles—the largest such intervention in its history.

Oil producers including the United States, Saudi Arabia, and the UAE also increased their production and carrying capacity. But the market's unsung hero may have been China, which drew on its huge stockpiles, leaving more oil in the market for other economies.

"OPEC has lost its primary role as global oil market manager," Kavonic says, referring to the cartel that seeks to maintain global oil prices. "It's now moved to China."

He notes that China's increased leverage in oil markets will have repercussions across the Pacific. "We can see how dependent Pacific Island nations are on diesel to keep the lights on. So we've seen countries in Asia not just have to manage their own imports but support the Pacific as well. Otherwise 30 years of Pacific policy could be undermined in a few months."

How long this resilience will last, however, is unclear—particularly now that tensions between Iran and the United States have flared up again and a prolonged closure of the Strait of Hormuz looks increasingly likely.

"We spent the last four months living on the oil market credit card. And if we continue at that rate, that credit card will be maxed out in a few months," Kavonic says.

This story was originally featured on Fortune.com.