Short is the new long. Companies from ExxonMobil to Chevron to Shell to Anadarko Petroleum are reducing or even selling their long-cycle assets in favor of buying short-cycle assets that deliver a return in three years or less. That means U.S. shales or the Permian Basin.

At press time, Marathon Oil became the latest to jump on the bandwagon, selling its Canadian oil-sands interests to enter the Delaware Basin by buying 70,000 acres.

The upshot is that today, U.S. producers are long—very long—recoverable oil and natural gas, but if drilling and production rise too much, oil and gas prices threaten to come up short.

“We could easily see lower oil and gas prices again, so we need to be positioned … ,” said Chesapeake Energy CEO Doug Lawler at CERAWeek by IHS Markit in March.

This warning surfaced repeatedly at the Houston event. CEOs from Anadarko Petroleum’s Al Walker to Total’s Patrick Pouyanné voiced concerns about stubbornly high oil inventories around the world, especially in the United States.

Continental Resources’ Harold Hamm also warned attendees at CERAWeek. “We’re about on equal footing with OPEC today. We have great potential to over-produce oil in this country, so we have a great responsibility to not do that,” he said.

Indeed, U.S. production is rising again, now back to 9 million barrels (bbl) per day with projections that it will go even higher next year. More American shale rigs could kill the fragile oil price rebound that’s underway, Hamm said. At a private dinner between OPEC leadership, the Saudis, Russia and about 20 U.S. independents during CERAWeek, these themes were prevalent. Pioneer Natural Resources chairman Scott Sheffield told the media that oil could drop back to the $40s if the trend continues.

This begs the question, will OPEC and non-OPEC producers, who have largely held to their promised production cuts, extend their agreement beyond June? They meet in Vienna in May to decide. OPEC Secretary General Mohammad Barkindo told CERAWeek attendees that OPEC is making the cuts, but U.S. shale production is offsetting those, and global oil inventories are not falling as fast as OPEC expected.

The day Lawler and Hamm spoke, the Energy Information Administration released stunning data on U.S. oil storage—at the highest level since 1982. Traders on Nymex responded with record-breaking volumes, sending near-month WTI futures down more than $2/bbl to go below $50 the next day. Even though Hamm sounded a cautionary note, his company, Continental, is back up to six stimulation crews in the Bakken with two more coming shortly, he said. He also touted how great were the company’s wells in Oklahoma’s Scoop/Stack play, some of them being the best in the company’s 50-year history.

“We’ll be back to our normal pace by the end of the year,” he said.

Walker said Anadarko will spend $1.3 billion this year on building up Delaware Basin infrastructure alone and will bring its successful playbook from the D-J to this Texas basin. More oil is a comin’.

Countless other E&Ps said on their fourth-quarter conference calls that they are beefing up their rig and frack activity and projecting production increases for 2017. Analysts slammed those whose budgets are creeping up, yet whose production increases don’t meet investors’ expectations. We are back to growth, moving away from balance sheet repair, but actual returns are anybody’s guess. Is the industry long hope and short discipline?

Nevertheless, the mood at CERAWeek was decidedly upbeat compared to last year’s event when oil prices languished below $30/bbl. The leaders of OPEC, Saudi Aramco and the International Energy Agency each mentioned the new efficiencies that U.S. producers have achieved as they lowered their breakeven prices. Those impressive technical advances are gradually being adopted all over the globe, as the CEOs of Statoil, Petrobras and Abu Dhabi National Oil Co., said at the conference. They are exploring more strategic partnerships and joint ventures as well.

U.S. producers said they are optimistic about the Trump administration’s pledge to cut corporate taxes, roll back regulations on business and open up areas for drilling. “The comments we’ve heard about regulation are positive … so I’m excited,” Walker said, “but we don’t think they should go too far in rolling back regulations on the Gulf of Mexico either; some of those changes were needed.”

During CERAWeek, Royal Dutch Shell sold out of its Canadian oil-sands projects, in favor of balance sheet repair, but behind that is the move to natural gas, and from long-cycle assets to short-cycle ones. Shell wants to reduce debt incurred by its acquisition of gas-rich BG Group. Around the world, majors and international oil companies are shifting their weight to gas and to shorter-cycle returns.

That brings up another area of debate heard at CERAWeek: How soon will the world transition off oil used for transportation in favor of electric vehicles and natural gas vehicles—and thus, what about long-term oil demand?

No one had a clear answer.