With Donald Trump winning the U.S. presidential election, the 14-country oil-producing cartel may have to battle a sourer outlook for the global economy and weaker demand for crude.

It also faces the prospect of increased U.S. oil output—a major bugbear for the Organization of the Petroleum Exporting Countries—given Trump’s pledge to open all federal land and waters for fossil fuel exploration.

OPEC’s internal dynamic could change, with Trump promising to tighten policies on Iran just as oil companies begin slowly to return to the Islamic Republic.

“Buckle up your seatbelts for a more turbulent and uncertain global economy that is ahead,” Pulitzer Prize-winning U.S. oil historian Daniel Yergin, vice-chairman of the IHS Markit think tank, told Reuters.

“The outcome of the U.S. election adds to the challenges for the oil exporters because it will likely lead to weaker economic growth in an already fragile global economy. And that means additional pressure on oil demand,” Yergin said.

Oil prices fell almost 4% early on Wednesday but recovered to trade up slightly at around $46 per barrel by 10:55 a.m. GMT.

OPEC will meet on Nov. 30 in an effort to curtail output and reduce the global oil glut that has seen prices more than halve since 2014.

OPEC sources said they expected oil to remain weak in the days and weeks ahead due to worries about the global economy and uncertainty about Trump’s policies for the Middle East.

“Oil is doomed,” one of the sources said.

A second source said the OPEC meeting in November might fail to have a strong impact on prices even if it strikes a deal to limit output: “I don’t think prices will go up much more than the current levels.”

Trump has promised to double U.S. economic growth but also pledged protectionist trade policies.

“This will have huge negative implications for Asia, given how much their GDP is tied to trade with the U.S. Hence it is negative for growth and oil demand, at least due to the uncertainty that Trump creates,” said Amrita Sen, of the think tank Energy Aspects.

Trump’s energy policies have been limited in detail so far.

But what he has said will be seen as supportive for the share prices of U.S. independent oil and gas producers as well as oil majors with large exposure to the U.S. shale industry such as Chevron (CVX), ExxonMobil (XOM), and Shell (RDS-A).

“Trump has vowed to lead a fossil-fuel revival to underpin job growth and has also put man-made climate change denial at the forefront of his energy policy,” JBC Energy analysts said in a note.

Trump said he was in favor of removing oil-sector regulations, opening federal land to drilling, and vowed to revive a major trans-Canadian and trans-U.S. oil pipeline project while pledging to support the coal industry.

The stocks of oil majors BP and Shell were down in line with the price of crude, while France’s Total underperformed peers.

Earlier this week, Total signed a deal with Iran to help it develop a huge gas field, becoming the first Western energy company to ink a major deal with Tehran since the lifting of international sanctions this year.

Trump has criticized the West’s nuclear deal with Iran, adding to uncertainty and frustrating Tehran’s push for foreign investment to revive its economy.

An executive from an oil major negotiating with Iran said that given Tehran wanted to repay investments slowly, maybe over five to 10 years, many oil firms would take a slow approach in finalizing deals until Trump’s policies became clearer.

“It is a significant amount of money that will be put at risk should sanctions be brought back,” the executive said.