section_path: History/21st century
section_name: 21st century
paragraph_text: 21st century
  
  The two oil price shocks had many short- and long-term effects on global politics and the global economy. They led to sustained reductions in demand as a result of substitution to other fuels, especially coal and nuclear, and improvements in energy efficiency, facilitated by government policies. High oil prices also induced investment in oil production by non-OPEC countries, including Prudhoe Bay in Alaska, the North Sea offshore fields of the United Kingdom and Norway, the Cantarell offshore field of Mexico, and oil sands in Canada.
  
  About 90 percent of vehicular fuel needs are met by oil. Petroleum also makes up 40 percent of total energy consumption in the United States, but is responsible for only one percent of electricity generation. Petroleum's worth as a portable, dense energy source powering the vast majority of vehicles and as the base of many industrial chemicals makes it one of the world's most important commodities.
  
  The top three oil-producing countries as of 2018 are the United States, Russia, and Saudi Arabia. In 2018, due in part to developments in hydraulic fracturing and horizontal drilling, the United States became the world's largest producer.
  
  About 80 percent of the world's readily accessible reserves are located in the Middle East, with 62.5 percent coming from the Arab five: Saudi Arabia, United Arab Emirates, Iraq, Qatar, and Kuwait. A large portion of the world's total oil exists as unconventional sources, such as bitumen in Athabasca oil sands and extra heavy oil in the Orinoco Belt. While significant volumes of oil are extracted from oil sands, particularly in Canada, logistical and technical hurdles remain, as oil extraction requires large amounts of heat and water, making its net energy content quite low relative to conventional crude oil. Thus, Canada's oil sands are not expected to provide more than a few million barrels per day in the foreseeable future.