MILAN, Dec 4 (Reuters) - The Organization of the Petroleum Exporting Countries (OPEC) will continue with its supply adjustments for the oil market, the OPEC Secretary General said on Saturday. "We will continue to do what we know best to ensure we attain stability in the oil market on a sustainable basis," Mohammad Barkindo said in a webinar organised by Italian think-tank ISPI. Oil prices fell on Thursday after OPEC and its allies stuck to their existing policy of monthly oil output increases despite fears a release from U.S. crude reserves and the new Omicron coronavirus variant would put renewed pressure on prices. read more Barkindo said in terms of oil demand the estimate at the moment was for a growth of 5.7 million barrels per day. "In 2022 we expect another 4.2 million," he said. He said the uncertainty and volatility on the markets was also due to extraneous factors such as the ongoing Covid pandemic and not necessarily the fundamentals of oil and gas. "Now we are on course of returning the level of consumption in 2022 to pre-COVID levels," he said. Barkindo said that the forecast was for oil and gas to account for more than 50% of the global energy mix in 2045 or even to mid century. "In all the pronouncements we had from Glasgow we have not yet seen any concrete road map or plans of how to replace this 50% ... without creating unprecedented turmoil in the energy markets," he said, referring to the Glasgow climate conference. "Oil and gas will be needed for the foreseeable future."