Up to 1% in U.N. crude oil and natural gas stocks are selling as investors take a breather from the oil and coal boom.

The Standard & Poor’s 500 index is up more by as much as 0.2% to 2,735.19.

Oil futures are up 0.6% to $34.85 a barrel.

Brent crude, the international benchmark, is up 2.7% to US$47.20 a barrel, and Nymex futures are flat at US$44.10. 

Oil markets remain volatile, as supply disruptions around the world and geopolitical tensions have caused supply disruptions in some parts of the world. 

“The world is facing the biggest oil supply disruption in decades,” said Jim McBride, chief market strategist at Wells Fargo Advisors in Dallas. 

The biggest U.K. refinery shutdown since 2007 has also put a squeeze on supplies in the U. S. and China.

“This is going to have an impact on U.A.E. supplies as well, especially if we get a bit of a spike in global demand,” said Kevin Davis, chief energy analyst at Barclays.

A major U.s. refinery is expected to shut down as the winter months approach, and there is growing concern that China will soon introduce its own strict new regulations that could push up the price of crude oil.

On Wednesday, Chinese Premier Li Keqiang said China’s energy security was under “great stress,” adding that it was “critical” for the country to make necessary adjustments to the global economy.

The U. N. climate change conference in Paris is scheduled for November 6-9, where delegates will decide on a global pact to curb emissions from the planet.

While some analysts expect the world’s largest economy to continue growing at a robust pace, the International Monetary Fund has warned that it is “uncertain” whether the global recovery can sustain itself.

Some investors are buying U. stocks in anticipation of oil prices rising in the near term, and the S&P 500 is up 4.4% to 3,633.69, while the Dow Jones Industrial Average is up 1.2%.